Workshop Manual







Volume IA - Engine, 16 valves



DR. ING. h. c. F. PORSCHE Aktiengesellschaft
As webpage by http://www.9ss1.dk/porsche944
944 Table of contents volume I-A



General

Technical data

Maintenance, Self-diagnosis

Fault diagnosis, DEE control unit
Connecting into the vehicle - 944S
Starting fault diagnosis
Functional test - actuator and input signal
List of test codes
System adaptation
Knock detection
Troubleshooting
List of fault codes
Clearing fault memory
Operating conditions for start of diagnosis
Operating instructions for System Tester 9288

Engine, Crankcase

Tightening torques for engine (16-valve)
Tolerances and wear limits
Engine, removing and installing

Engine, Crankshaft drive, Pistons

Notes on assembly for pistons, from Model 87 onward
Checking pistons and cylinder bore
Pistons from Model 89 onward
Installing cover for oil-centrifuge partition

Engine, Cylinder head, Valve drive

Camshaft salling, checking and adjusting
Camshaft salling, checking and adjusting for Model 89 onward
Applying the TOC mark on the camshaft sprocket
Camshafts and cylinder head, removing and installing
Cylinder head, installing and tightening
Camshafts, installing
Camshaft seal, installing
Camshaft specifications
Chain tensioner, removing and installing
Cylinder head, disassembling and assembling
Valve springs, removing and installing with Sauer tool
     Page


0.9




03 - 1
03 - 3
03 - 5
03 - 7
03 - 13
03 - 15
03 - 17
03 - 19
03 - 29
03 - 31
03 - 32
03 - 33



10 - 0101
10 - 0102
10 - 101



13 - 101
13 - 102
13 - 103
13 - 105



15 - 101
15 - 104 a
15 - 104 b
15 - 105
15 - 110
15 - 111
15 - 112 a
15 - 112 b
15 - 113
15 - 115
15 - 118




Table of contents
Printed in Germany - XXIV, 1991
1
volume I-A Table of contents 944




Machining mating face, cylinder head
Vaive springs, removing and installing, removing valve stem seal
Valve stem seal, installing
Checking valve guides
Replacing valve guides
Checking valve seat wear limit
Valve seats, checking and machining
Checking and adjusting installation length of valve springs

Engine - Lubrication

Replacing engine oil and oil filter
Pressure-reduclng valve, removing and installing

Engine - Coating

Checking cooling and heating system for leaks

Fuel supply

Replacing fuel filter, checking injection lines for leaks and tightness
Checking delivery rate of fuel pump
Line routing, fuelsystem, M 44.40

Fuel preparation - L-Jetronic/regulation

Replacing air filter cartridge, checking intake-air guide hoses
Testing and adjusting specifications
Checking fuel pressure
Checking idle speed and CO - with catalytic convertor
Checking idle speed and CO - without catalytic convertor
Replacing air filter cartridge for Model 89 onward

Exhaust system

Exhaust system - check tightness of flanges

Ignition system

Equipment table
DEE control unit coding - 944 S, Model 87 onward
Replacing spark plugs
Equipment table, Model 89 onward
DEE control unit coding - 944 S 2, Model 89 onward
DME-Diagnosing / Troubleshooting
     Page

15 - 120
15 - 121
15 - 122
15 - 123
15 - 125
15 - 130
15 - 131
15 - 133



17 - 101
17 - 102



19 - 101



20 - 101
20 - 102
20 - 103



24 - 101
24 - 102
24 - 103
24 - 105
24 - 106
24 - 107



26 - 101



28 - 101
28 - 103
28 - 104
28 - 105
28 - 107
D-24/28-1




2 Table of contents
Printed in Germany - XXIV, 1991
944 General





TYPE 944 S (16-VALVE ENGINES) - '87 MODELS ONWARD






0.9








Printed in Germany - XIII, 1987 Technical Data 0.9
General 944



TECHNICAL DATA

(Adjustment specifications and wear data are stated in the appropriate Repair Groups)

Note: US values are stated in parentheses

DRIVE UNIT

Internal engine designation

Number of cylinders

Bore

Stroke

Displacement (actual)

Compression ratio

Max. engine output to
80/1269/EC

Net power, SAE J 1349

at engine speed

Max. torque to
80/1269/EC

at engine speed

Net torque, SAE J 1349

Max. spec. power output

Net power, SAE J 1349

Fuel octane rating


Max. perm. engine speed

Engine weight (dry)

ENGINE DESIGN

Type




mm/in.

mm/in.

cc/in.3



kW/PS


kW/HP

rpm

Nm/kpm


rpm

Nm/lbft

kW l/HP l

kW l/HPI

RON/MON


rpm

kg/lbs
M 44/40

4

100/3.94

78.9/3.11

2479/151

10.9 : 1

140/190 - 135/184 Australia


140/188

6000

230/23.5 - 225/22.9 Australia


4300

230/170

56.5/76.6-54.5/74.2 Australia

56.5/75.8

95/85 - 92/82 unleaded Australia
(95/85 premium unleaded)

6840

175/386



4-cylinder, 4-stroke in-line spark ignition
engine with two balance shafts


0.10 Technical Data Printed in Germany
944 General



Crankcase

Crankshaft

Crankshaft bearings

Connecting rods

Connecting rod-bearings

Pistons

Balance shafts

Balance-shaft bearings

Cylinders

Cylinder head

Valve guide

Valve arrangement


Valve timing


Camshaft


Camshaft drive

Balance-shaft drive

Valve clearance

Two-part light alloy crankcase

Forged, 5 bearings

Plain

Cast, opt. sinter-forged

Plain

Light alloy, cast

Forged

Plain bearings with bearing shells

Light alloy

Light alloy

Press-fit, special brass

2 intake, 2 exhaust
overhead V

Two overhead camshafts, hydraulic
bucket tappets

Without bearing shells, carried in
cylinder head

Toothed belt and internal chain

Toothed belt

Self-adjusting (hydraulic)

Timing                Intake opens
Intake closes
Exhaust opens
Exhaust closes
4 after TDC
40 after BDC
36 before BDC
4 before TDC








Printed in Germany - XIII, 1987 Technical Data 0.11
General 944



ENGINE COOLING



ENGINE LUBRICATION

Lubrication





Oil pressure


Oil-pressure indicator

Max. oil temperature

Oil consumption

EXHAUST SYSTEM







EMISSION CONTROL





HEATING












n = 5000 rpm






l/1000 km
Sealed cooling system, electric fan
with thermoswitch, antifreeze effective
to - 25C



Forced-feed lubrication with
sickle-type pump, oil filter and
oil-water heat exchanger in main oil
flow and secondary water flow
integrated in crankcase

Approx. 4 bar, at operating
temperature

Pilot lamp and pressure gage

140C

Up to 1.5

Standard
2 double-wall manifolds, branch pipe to
primary muffler, 1st and 2nd
secondary mufflers
Option: M298 or M299 and USA and
Australia as standard, catalytic
converter instead af primary muffler

Standard: engine-internal
Option: M298 or M299
and Australia
heated oxygen sensor with 3-way
catalytic converter

Hot-water heating with heat exchanger
and blower












0.12 Technical Data Printed in Germany
944 General



FUEL SYSTEM

Injection


Fuel delivery

Fuel octane rating






Fuel consumption
to 80/1268/EC or
ECE R 15/04

Constant 90 km/h
Constant 120 km/h
EC exhaust urban
cycle

ELECTRICAL SYSTEM

Suppression

Battery voltage

Battery capacity


Alternator (output)


Ignition

Firing sequence

Ignition timing








RON/MON










l/100 km
l/100 km

l/100 km





V

Ah


A/W



DME
Digital Motor Electronics

1 electric fuel pump

Standard:  95/85 - European standard
premium unleaded
possible
Opt./M298:  95/85 unleaded
- European standard premium -
Australia: 91/82 unleaded

Standard:



6.7
8.3

12.5



ECE-R 10 and 72/245/EC

12

50 - optional 63,
sports package 36

115/1610
- sports package: 90/1260

By DME

1-3-4-2

By DME










Printed in Germany - XIII, 1987 Technical Data 0.13
General 944



BODY DESIGNS       

Integral all-steel body with front air dam and rear
spoiler
- as coupe, opt.: removable hardtop panel, also
  available with fog lamps set in PU front air dam as
  optional extra.

DIMENSIONS (at DIN curb weight)

Length

Length with opt.
extra US bumpers

Width

Height

Wheel base (in
design pos.)

Track:

Front



Rear




Ground clearance
(at per. total
weight)

Bed clearance
(at per. total
weight)

Overhang angles:

Front

Rear
mm/in.       

mm/in.


mm/in.

mm/in.

mm/in.




mm/in.



mm/in.




mm/in.



mm/in.
4230/165.354

4290/168.90


1735/68.31

1275/50.20

2400/94.49




1477/58.2
1477/58.2
1477/58.2

1451/57.1
1451/57.1
1451/57.1
1442

120/4.72



53/2.09





14

15
(4290/168.90)











Rim size

7 J x 15
7 J x 16
8 J x 16

7 J x 15
7 J x 16
8 J x 16
9 J x 16





0.14 Technical Data Printed in Germany
944 General



WEIGHTS

- to DIN 700 20 -
Curb weight


Front


Rear


Total


Per. axle load

Front


Rear

Per. total
weight

Per. trailer
load

Braked trailer


Unbraked
trailer


Max. car/
trailer weight


Max. drawbar
load



Per. roof load

With genuine
Porsche roof
transport
system



kg/lbs


kg/lbs


kg/lbs




kg/lbs


kg/lbs

kg/lbs





kg/lbs
kg/lbs

kg/lbs
kg/lbs


kg/lbs
kg/lbs



kg/lbs
kg/lbs


kg/lbs


kg/lbs
Standard


640/1411
(650/1433)

640/1411
(650/1433)

1280/2822




730/1609


900/1984

1600/3527





1200/2646
1200

500/1102
500


2760/6085
2760



50/110
50


35/77


75/165
Sports package


630/1389


610/1345
(630/1389)

1240/2734
(1260/2778)



730/1609
(720/1587)

900/1984

1600/3527
(1550/3417)




up to 16% gradient
for Italy

up to 16% gradient
for Italy



for Italy




for Italy
up to 100 km/h
Australia,
standard

640/1411


640/1411


1280/2822




730/1609


920/2028

1620/3571


Printed in Germany - XIII, 1987 Technical Data 0.15
General 944



CAPACITIES

Engine (measurement with dipstick
as per Driver's Manual is definitive)


Engine oil

Engine coolant

Transmission with differential



Fuel tank


Brake-fluid reservoir

Windshield and headlight washing
fluid reservoir



Proprietary HD oils to APl
classification
SE or SF, see Driver's Manual

Approx. 6.0 l

Approx. 8.5 l

Approx. 2.0 l hypoid oil, SAE 80
to MIL-L 2105, APl classification
GL 4

Approx. 80 l, including approx.
8 l reserve

Approx. 0.2 l

Approx. 0.6 l
PERFORMANCE

Maximum speed

Acceleration from  0-100 km/h*
(0-60 mph)*
(1/4 mile
from standing
start)*

Kilometer from standing start*

CLIMBING PERFORMANCE

In % (slip limit)


km/h/mph  

s
s


s

s



1st gear
2nd gear
3rd gear
4th gear
5th gear


228/142

7,9
(7.7)


(15.4)

27.8



62%
35.6%
21.5%
13.3%
9.4%

*DIN curb weight and half of payload






0.16 Technical Data Printed in Germany
944 General



Technical data - Type 944 52 - Model 89

(Values for adjustment and wear are to be found in the respective repair groups)

Notes: USA values are given in brackets

Drive unit


Internal engine designation

Bore

Stroke

Displacement (actual)



mm (in.)

mm (in.)

cm3(in.3)
Manual transmission M 44.41 (3.0 I)

104 (4.09)

88 (3.46)

2990 (182.5)
Displacement (rounded down)

cm3 2969
Compression ratio

Max. engine power
88/195/EEC
Net power, SAE J 1349
at engine speed

Max. torque
88/195 / EEC
(Net torque, SAE J 1349)
at engine speed

Max. output per litre
DIN 70020
(SAE J 1349)

Speed governed by
fuel cut-off

Engine weight (dry)



kW (HP)
kW (HP)
rpm


Nm (kpm)
Nm / lbft
rpm


KW/I (HP/I)
KW/I (HP/I)


rpm

kg
10.9: 1


155 (211)
155 (208)
5800


280 (28.5)
280 (207)
4100


51.8 (70.6)
51.8 (69.6)


6480 +- 20

175











Technical data
Printed in Germany - XIX, 1989
0.17
944 Maintenance, Self-diagnosis 03



DME control unit error diagnosis

DME control unit error diagnosis 944 S
as from 88 model


As from model year 88, the DME control unit
944 S is capable of a self-diagnosis. That is to
say, the control unit is capable of detecting,
storing and displaying system errors. The con-
trol unit capable of diagnosis is identified by
an altered part number. A specially developed
diagnostic tester (special tool No. 9268) is
then used to read out the error memory and
to test specific components and control sig-
nals af the fuel and ignition system.


The DME control unit for 944 S
87/793


Important: Before diagnosis, the battery or
the connector of the DME control unit must
not be disconnected as otherwise the error
memory will be erased.















DME control unit error diagnosis
Printed in Germany - XVI, 1987
03 - 1
03 Maintenance, Self-diagnosis 944



Display


Display on the 944 S DME control unit


               

LED off Test sequence terminated / igniti

  

Flashing LED          Error code / test code

  

LED on Ignition on




03 - 2 DME control unit error diagnosis
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Connection in the 944 S


In the 944 S, the diagnosis socket is attached
to a separate cable harness located above the
DME control unit.

87/1012


Ignition off

After connecting the tester, the following dis-
play must appear.

Display:



If this is not the case, check the tester ter-
minals or check the power supply of the diag-
nosis socket in the car by referring to the cir-
cuit diagram.
      Diagnosis socket in the car

Pin 1 = terminal 15

Pin 2 = terminal 31

Pin 5 = terminal 30

Pin 9 = Hall generator


87/908






Connection in the 944 S
Printed in Germany - XVI, 1987
03 - 3
03 Maintenance, Self-diagnosis 944



Tester cable

Diagnosis

Pin 1

Pin 2

Pin 3

Pin 4

Pin 5

Pin 6

Pin 7

Pin 8

Pin 9

Pin 10

Pin 11

Pin 12

plug

 

 

 

 

 

unused

unused

unused

unused

unused

 

 

Round plug

Pin 4

Pin 1

Pin 7

Pin 6

Pin 2











Pin 5

Pin 3

        
34
      Switch on the ignition

Display:



The ignition must not be switched off
during the entire error diagnosis procedure.








03 - 4 Connection in the 944 S
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Starting error diagnosis


Condition:
Engine off
Ignition on

Display:



Press the green key until the clear symbol
appears on the function display.


Display:


Clear symbol


The diagnosis sequence for the DME control
unit then takes place.
      If an error is displayed - take the note of the error (e.g. 1211).

Display:



The error is displayed until the green key is
again pressed on the tester. The next
error code is then displayed. if applicable.

This must be repeated until 1000 appears on
the display.




If no error has occurred. the following display
appears.


Display:











Starting error diagnosis
Printed in Germany - XVI, 1987
03 - 5
03 Maintenance, Self-diagnosis 944



Press the green key until the clear symbol ap-
pears on the function display. The following
display must then appear.

Display:



This now terminates diagnosis of the DME
control unit.

If one or several errors (up to 5) has/have
been displayed, the error memory must be
reset; see chapter (Resetting the error
memory).



























03 - 6 Starting error diagnosis
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Actuator and input signal function
checking


An actuator and input signal function check
can be carried out independently of an error
diagnosis. This function check tests individual
components or electrical signals with respect
to their functioning or signal paths. Functions
ara triggered from the diagnosis tester. During
functional checking of components, these
must audibly or tangibly operate and can thus
be detected as being electrically in proper
working order or defective.

An error display via the tester is not possible in
this mode, but faulty input signals or their
wiring connection ara detected by the tester.
      Starting actuator and input signal
function check


Ignition off

Press the yellow key until the function symbol
(see display) appears on the function display.

Display:



Prass the green key until the clear symbol ap-
pears on the function display.

Display:



Switch on the ignition within 8 seconds.
















Actuator and input signal function checking
Printed in Germany - XVI, 1987
03 - 7
03 Maintenance, Self-diagnosis 944



Press the green key until the ctear symbol ap-
pears on the function display. This activates
the first testing step and the injection valves
are activated.

Display:



The injection valves must all operate audibly
or tangibly.



Note:

If later attempts are made to start the engine,
starting difficulties may occur because a slight
residual amount of fuet is injected during this
testing step.

The testing steps remain in operation until the
green key is again pressed on the tester and
the clear symbol appears.
      The next testing step is initiated by again
pressing the green key.

Refer to the test code list for the sequence of
testing steps.



















03 - 8 Actuator and input signal function checking
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



As from the "idle contact" testing step, specific
controls must additionally be operated on the
car for the purpose of function checking.

Idle contact display:



Slightly press the accelerator. The LED must
go off after approx. 20 mm and the display will
appear After approx. 3 s.

Display:



If this is not the case, an error has occurred in
the area of the idle contact (see Idle contact
troubleshooting).

If the display 0000 does not appear, it is pos-
sible to switch at all times to the next testing
step. Press the green key until the clear
symbol appears.
      Initiate the full load contact testing step.

Display:



Slowly press the accelerator until the full
throttle position is reached.
The LED must go off and the display will
appear after approx. 3 s.

Display:



If this is not the case, an error has occurred in
the area of the full load contact (see Full load
contact troubleshooting).












Actuator and input signal function checking
Printed in Germany - XVI, 1987
03 - 9
03 Maintenance, Self-diagnosis 944



Initiale the air-conditioning control terminal 41
testing step.

Display:



Switch on the air-conditioning system.
The LED must go off and the display will
appear after approx. 3 s.

Display:



If this is not the case, an error has occurred in
the area of the air-conditioning system's wiring.

In the event of an error, check with reference
to the circuit diagram.
Do not switch off the air-conditioning system.
      Initiate the air-conditioning control terminal 40
testing step.

Display:



Switch off the air conditioning system.
The LED must go off and the display will
appear after approx. 3 s.

Display:



If this is not the case, an error has occurred in
the area of the air-conditioning system's wiring.

In the even! of an error, check with reference
to the circuit diagram.














03 - 10 Actuator and input signal function checking
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Press the green key until the clear symbol
appears.

Display:



End of the actuator and input signal function
checks.
































Actuator and input signal function checking
Printed in Germany - XVI, 1987
03 - 11
03   944




















































03 - 12 Blank page
 
944 Maintenance, Self-diagnosis 03



Test code list



Test code Components


1311

1321

1322

1332

1333

1334

1335
     






Injection valves

Rotary idle controller

Solenoid valve - tank bleeding

Idle contact

Full load contact

Air-conditioning/AC switch

Air-conditioning/compressor coupling




























Test code list
Printed in Germany - XVI, 1987
03 - 13
03   944




















































03 - 14 Blank page
 
944 Maintenance, Self-diagnosis 03



System adaption

System adaption can be carried out with the
tester. That is to say. the electronic idle control
in the DME control unit is adapted to the
actual air throughput and to the current
condition of the engine.

Note:

For system adaption, it is necessary for the
engine to be at operating temperature.

Ignition off

Press the yellow key the number af times
required for the function symbol to appear
on the function display.

Display:



Press the green key until the clear symbol
appears on the function display. Start the
engine within 8 seconds. Allow the engine to
idle until the system adaption code appears.
Display:



The engine must now idle for at least 30
seconds.

System adaption is then completed.

Ignition off


















System adaption
Printed in Germany - XVI, 1987
03 - 15
03   944




















































03 - 16 Blank Page
 
944 Maintenance, Self-diagnosis 03



Knock detection

Before knock detection is carried out, error
diagnosis must first of all be performed to
guarantee that no electrical error has occurred
in the area of the knock control and the knock
sensors.

Knock detection should not be carried out if
the customer has complained about poor out-
put or too high a consumption, for instance.

Condition:

The engine most be at operating temperature
during the test. Testing most be carried out
during a test drive or on the roller test stand.
      Knock detection

Engine at operating temperature

While the engine is running, simultaneously
press the yellow and the green key until the
knock detection function symbol appears
on the function display.

Display:



The tester is new in knock detection mode.

Note:

Normal driving is a prerequisite for the
test drive (roller test stand).


Start the test drive (roller test stand).
Press the green key until the clear symbol
appears on the function display.

Display:










Knock detection
Printed in Germany - XVI, 1987
03 - 17
03 Maintenance, Self-diagnosis 944



The tester is now active. If knocking occurs,
this will be indicated by the tester, e.g.:

Display:



After the expiry of 10000 ignitions. the function
display will change to "r".

Display:



Counting is now complete.

The number af knocks is displayed in per mill.
In this example. 25 knocks have occurred.

Knock detection must be carried out until the
function display switches over from the clear
symbol to the knock detection symbol. This is
always the case once 10000 ignitions have
occurred. All occurring knocks are added up
and displayed as the end result.
      To restart knack detection. the green key
must be pressed until the clear symbol again
appears.

A knock display of > 2.5 (25) draws attention
to an error.






Error possibilities:

Defective cup tappets
Conical rod damage
Crank mechanism damage

To terminale knock detection mode. the
green and yellow keys must be pressed
simultaneously until the display appears.

Display:
















03 - 18 Knock detection
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Troubleshooting

Diagnosis using the tester can refer only to
the error path, but not to a defective component.




Note:

Before troubleshooting, the entire error
memory must be read out.
      Error code 1111

The supply voltage is too low
< 10 V or too high > 16 V.


Possible causes for too low a supply voltage:

Battery exhausted

Poor contact on the grounding strap
Poor contact on the control unit

A defective regulator may be the cause of
too high a supply voltage.






























Troubleshooting
Printed in Germany - XVI, 1987
03 - 19
03 Maintenance, Self-diagnosis 944



Error code 1112

This error code indicates an error in the area
of the idle contact.

Possible error:

Ground fault
Switch stuck

Testing the idle contact

Extract the plug from the DME control unit.


32
      Connect a ohmmeter between terminal 52
and terminal 24 on the DME plug.

Display:

Throttle valve closed: R < 10

Throttle valve open: R =  

Switchover must already occur if the throttle
valve is only slightly open (approx. 1).

If the values ara not reached during this testing
step, measurement must be repeated directly
on the throttle valve switch.














03 - 20 Troubleshooting
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Error code 1113

This error code draws attention to an error in
the area of the full load contact.

Possible errors:
Ground fault
Switch stuck

Testing the full load contact

Connect an ohmmeter between terminal 53
and terminal 24 on the DME plug.

Display:
Throttle valve closed:                   R =    
Throttle valve in full load position: R < 10

The switching point must be briefly before full
load.

If the values are not reached in this testing
step, measurement must be repeated directly
on the throttle valve switch.


      Error code 1114

This error code draws attention to an error in
the area of the engine temperature sensor
(NTC 2).





87/912

Possible errors

Ground fault
Short to positive
Wire discontinuity
NTC 2 defective


Testing the engine temperature sensor.

Connect an ohmmeter between terminal 45
and terminal 24 on the DME plug.













Troubleshooting
Printed in Germany - XVI, 1987
03 - 21
03 Maintenance, Self-diagnosis 944



Display

0C =
15 - 30C =
80C =
100C =
4400 -
1400 -
250 -
160 -
6800
3600
390
21

If the values are not reached in this testing
step, measurement must be carried out
directly on the engine temperature sensor.

The engine temperature sensor (NTC 2) in-
forms the control unit about the current engine
temperature. It results in mixture enrichment
during cold starts or hot running.


      Error code 1121

This error code draws attention to an error in
the area of the air-flow sensor.



87/907

Possible errors:
Ground fault
Short to positive
Wire discontinuity


During this test, the plug af the DME
control unit must be plugged in.




















03 - 22 Troubleshooting
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Testing the power supply of the air-flow
sensor:


Ignition on

On the extracted plug of the air-flow sensor, a
voltage of 5 V +- 0,5 V must be measurable
between terminal 3 (positive) and terminal 4
(negative) (if necessary, check by reference
to the circuit diagram).


             

33

Testing the air-flow sensor

From the extracted plug of the air-flow sensor,
link plug terminal 3 to air-flow sensor plug ter-
minal 3 and plug terminal 4 to air-flow sensor
plug terminal 4 using an auxiliary cable.
Measure the voltage between terminal 2 of
the air-flow sensor and ground.

Display:

approx. 250 - 260 mV

Detach the top of the air filter.

Using a non-metallic tool, slowly force the
airflow sensor valve to full load position.
      A voltage rise must be observed during this
time.

Display:

approx. 0.2 V - ca. 4.6 V

No abrupt voltage changes must be observed
during opening or closing. (Abrupt voltage
changes. i.e. the air-flow sensor is defective).









Troubleshooting
Printed in Germany - XVI, 1987
03 - 23
03 Maintenance, Self-diagnosis 944



Error code 1123

When this error code appears, the Lambda
control has detected too rich ar too lean
a mixture.

Possible causes for too lean a mixture:

Lambda probe ground fault
Intiltrated air on the intake side
Intiltrated air on the exhaust side of the
Lambda probe
Injection valve does not open
Ignition cut-out
Fuel pressure too low

Possible causes for too rich a mixture:

No partial vaccum on the pressure regulator
Injection valve does not close
Return to the fuet tank clogged.


      Error code 1124

This error code draws attention to an error
in the area of the Lambda probe.

Possible errors:

Ground fault
Short to positive
Wire discontinuity


Testing the Lambda probe signal.



Figure 87/906

Disconnect the Lambda probe plug.


Note:

The voltage af the Lambda probe must only
be measured using a digital voltmeter, or
only using a comparable measuring instru-
ment with an internal resistanee (Ri) of no
less than 10 M.









03 - 24 Troubleshooting
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Measure the voltage between pin 1 and engine
ground.


                       

35

The voltage is within the range of approx. 150
mV - 900 mV depending on the mixture
composition.

Check the cable harness to the DME control
unit with reference to the circuit diagram.


      Error code 1125

This error code indicates an error in the area
of the intake air temperature sensor (NTC 1)
in the air-flow sensor.

Possible errors:

Ground fault
Short to positive
Wire discontinuity
NTC 1 defective

Testing the intake air temperature sensor.

Connect an ohmmeter between terminal 44
and terminal 26 on the DME plug.

Display:

0C =
15 - 30C =
40C =
4400 -
1400 -
1000 -
6800
3600
1300

If the values are not reached during this
testing step, measurement must be carried
out directly on the intake air tempertaure
sensor.


Connect an ohmmeter between pin 1 and
pin 4 on the air-flow sensor.

Display: as above













Troubleshooting
Printed in Germany - XVI, 1987
03 - 25
03 Maintenance, Self-diagnosis 944



Error code 1131

This error code draws attention to an error in
the area of knock sensor 1.



87/911


      Error code 1132

This error code draws attention to an error in
the area of knock sensor 2.



87/910

Error testing of the knock sensors is an active
error test, i.e. error testing is carried out during
driving.

If an error has occurred, first check the wiring
for a ground fault, a short to positive and for
continuity with reference to the circuit diagram
before replacing the knock sensor.









03 - 26 Troubleshooting
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Error code 1133

Error code 1133 draws attention to an error in
the area of the knock control in the DME con-
trol unit. If this error code appears, the DME
control unit must be replaced.


      Error code 1134

This error code draws attention to an error in
the area of the Hall generator.


87/904

Possible errors:

Ground fault
Short to positive
Wire discontinuity



Testing the Hall generator signal

Using a suitable auxiliary æble, connect an os-
cilloscope to the diagnosis plug, pin 9 (square-
wave signal) and pin 2 (ground). If the Hall gen-
erator signal is O.K., the following picture must
appear on the oscilloscope's screen.













Troubleshooting
Printed in Germany - XVI, 1987
03 - 27
03 Maintenance, Self-diagnosis 944





Testing the Hall generator's power supply

Disconnect the Hall generator's connector.

Ignition on



                       
36


A voltage of 12 Volt +- 1 V must be
measurable between pin 1 (positive) and pin 3
(negative). If this is not the case, check the
wiring with reference to the circuit diagram.


      Error code 1141

Error code 1141 draws attention to an error in
the area of the DME control unit. If this error
code appears, the DME control unit must be
replaced.










03 - 28 Troubleshooting
Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis 03



Error code - List

Error code                              

1500

1000

1111

1112

1113

1114

1121

1123

1124

1125

1131

1132

1133

1134

1141
Error path

No error

Output end

Supply voltage too low/high

Idle contact

Full load contact

NTC 2

Air-flow sensor

Lambda control detects a too rich / too lean mixture

Lambda probe signal not correct

NTC 1

Knock sensor 1

Knock sensor 2

Knock control in the control unit

Hall generator signal

DME control unit



A digit 2 (e.g. 1211) may appear in the second error code digit position to indicate "sporadic
errors", i.e. an occasionally occurring error.

This does not apply to error codes 1000 and 1500.








Error code - List
Printed in Germany - XVI, 1987
03 - 29
03   944




















































03 - 30 Blank page
 
944 Maintenance, Self-diagnosis 03



Resetting the error memory

Once the DME control unit error diagnosis
has been completed. this is completed by
error code 1000. The error memory cannot
be reset as follows until this error code
appears:

The yellow key must be pressed until the
function symbol (see display) appears on
the function display.

Display:


Function symbol

The green key must be pressed until the clear
symbol appears on the function display.

Display:


      The error memory is reset if the LED goes off
and the function display changes to 0000.

Display:






Note:

A test drive must be carried out after resetting
the error memory.

At the same time, pay attention to the following:

1.   The engine must be at operating tempera-
ture. i.e. at least 80C.

2. The duration ot the test drive (minimum 6
minutes).

3. At the end ot the test drive. run the engine
for at least 60 seconds without opening the
throttle valve.

After the test drive, read out the error memory
once again.











Resetting the error memory
Printed in Germany - XVI, 1987
03 - 31
03 Self-diagnosis 944



Operating conditions for start of diagnosis




  Systems
Ignition on
Engine standing still

Engine running

  944 S / 944 S2

  DME

  Airbag

  Alarm system




yes               

yes

yes



to n < 2000 rpm

yes

yes
















Webdesign from www.9ss1.dk/porsche944


















03 - 32 Operating conditions for start of diagnosis
Printed in Germany - XXIV, 1991
944 Self-diagnosis 03



Operating instructions for System Tester 9288













Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
03 - 33
03 Self-diagnosis 944


1. General information
1.1 Application
The Systemtester 9288 (BOSCH KTS 301) is a microprocessor-con-
trolled self-diagnosis tester.
All systems which have a diagnosis interface as per ISO Standard can
be tested with this tester. The following tests are possible:
* Reading out the fault memory
* Testing of the actuators
* Testing the circuit inputs
* System adaptation
* Engine-knock detection
* Sensor and status checks, tire-pressure monitoring (RDK)
The Systemtester 9288 is a high-quality pjece of electronic equip-
ment In order to prevent damage to the equipment as a result of
improper use, please read the information in the operating
instructions carefully and comply with it.
In addition. the instructions (specifications) of the vehicle manufac
turer are also to be observed.
If the tester should fail, check the following points before sending it
in for repair:
1. Has the tester been operated incorrectly?
2. Is the battery sufficiently charged?
3. Is the adapter cable OK?
(Please note when checking the adapter cable that a highly sensi-
tive electronic matching circuit is installed in the vicinity of the 19-
pore plug).
1.2 Construction (Fig. 1)
No. Description Function Remarks
1 LCD indicator Dot matrix 5 x 8
4 lines each with 20 characters
Foreign languages possible
Illumination
If the Systemtester 9288 is switched on
without the program module, following
the self-test the tester switches off auto-
matically and informs the user that the
program module is not fitted.
2 Keyboard
Keys 1, 2, 3 = Selection key
Keys <  > = Previous peget next page
Key H = Help menu, e.g.:
Illumination
Screens stored
Control-unit overview
Setting up printer
Switching off unit
Key N = Return to the next higher
program level following
termination of a test
sequence or, during a test
sequence, return to the
last display
Key = Storing indication
Key = Playing back
stored reading

Switching on = Press any key
Switching off
(automatic)
= 180 s after last
depression of a key or
if no data stream flows
across the seriel
interface.

The last fjeld in the top right-hand corner is
filled completely, this means that this is a
stored figure and not an actual,
real-life figure.
3 Power supply



If the voltage is not sufficient,
"Charge battery" appears
on the display. If this is
not done, the unit switches
itself off.
Fitted accumulator with NiCd batteries.
The Systemtester 9288 must be switched off
during the initial battery charging process.
Charging time > 8 hours
Discharged upon delivery. Following charge:
Operating time:
4 - 8 hours without scale illumination
1 - 2 hours with scale illumination
Connection to vehicle battery by means
of vehicle-specific adapter lead (see 1.4)
Connection through ISO-interface
Charging voltage supply
Battery charger (accessory) For test operation and for charging
the NiCd batteries.
4 Connection for
Input and output devices
Connection facility for Printer
e. g. Epson, IBM. Hewlett Packard (HP)
The Systemtester 92BB transmits data with
the following configurations:
8 data bits / 1 start bit / 1 stop bit /
No parity (for printer matching)
5 Connection for vehicle
specific adapter lead
Reading out the data Input for flashing-code support
6 Plus-in programme module
(see also Figure 2)
        C-MOS !
Do not touch plug !
Operating system
LCD drive
Keyboard
Interface communication
Computations and data conversions
Plug in module:
remove rubber protector,
insert modul e fully.

03 - 34 Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
944 Self-diagnosis 03


1.3 Battery charger run off mains voltage (Figure 3)
- Accessory -
Item 1  Charger with connecting cable, 1.5 m long
Item 2  8-pin AMP plug


1.4 Vehicle-specific adapter cable
Porsche No. 000 721 928.81


1.5 Connecting lead (Figure 4)
- Self-fabrication -
for printer, programme load station or similar unit.
For interface-trunk assignment, see manual of corresponding unit.
Printer cable for standard D 25
BOSCH No. 1 684 465 193
Printer cable for EPSON
BOSCH No. 1 684 465 194



2. Connection
The following points must be observed:
- No gear must be engaged on the vehicle (Automatic transmission
  in position N - P) - Danger of Accident!
- ALL work on the vehicle must only be carried outwith the ignition
  switched off.
After having connected the vehicle-specific adapter cable, the in-
structions listed under "3" ara displayed on the Systemtester 9288:


2.1 Charging with the battery charger (Fig. 3)
Connecting the Systemtester 9288 to the battery charger.
(Fig.1, pos.5).


2.2 Diagnosis
Connecting the Systemtester 9288 to the diagnosis plug in the
vehicle by means of the vehicle-specific adapter cable.
Switch on the tester and proceed according to the instruetions
displayed.



3. Testing
Scope of module:
Guidance through the menu, communication with the ECU, reading
out the error memory and selection of the "Help" menus, actuator
diagnosis, circuit inputs and system adaptation, engine-knock detec-
tion, sensor and event check for the tire-pressure monitor (RDK).


3.1   
Reading-out the error memory
Connect the Systemtester 9288 (see 2.)
Switch on the Systemtester,
(possible with every key!)
Display:

      PORSCHE
Eprom modul
Mod. intro. xx.xx.xx


eng

If a specific instruction does not appear in a display, it is always
possible to proceed by pressing the button >.
Due to the fact that the Systemtester 9288 can store error displays
(see Chapter 3.7), the following display will appear if errors have
been stored in the image memory:

Stored displays
erased ?
1 = yes
3 = no

Key 3
Display:

Print out
displays:

continue:

H

>

H = Help menu (see 3.6) or key 1
Display:

       Vehicle types
1 = 944 S
2 = 911 Carrera 4
3 = 928 S 4

Selection of the vehicle type with key 1, 2 or 3.
After the vehicle type has been selected, the following
instruction appears:

Connect adapter
cable to veh. plug.
Ignition "ON".
After completion:



>

The following then appears:

Wait for
Data

Break off test:



N

After a short pause. the Systemtester 9288 reperts all the sys-
tems that are installed in the particular vehicle. If a system is pre-
ceded by " # ", this means that at least 1 error is stored in that
particular system.

Examples:

      Installed systems
1 = # LH
2 = # EZK
3 =    RDK

The particular system can be selected by means ef key 1, 2 or 3.
After selection (for instance with key 1), the following display
appears:

      LH
System:
Ser. No.:
RB. No.:

L01 LH-JET
92861812313
0280002507


Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
03 - 35
03 Self-diagnosis 944


After pressing the key > , a selection menu is displayed:

Menu
1 = Fault memory
2 = Drive links
3 = Input signals



>

< Menu
1 = System adaptation



In the example - press key 1. There then follows the display of
the number of errors which are stored (if any).

Number of
faults

- 2 -

Proceed with key >

Additional info to
every display with
key 1
continue:



>

Proceed with key >
Error output:

1: Engine
temperature sensor 2
Short to ground
not present

If key 1 is pressed instead of the > key, the corresponding error
code display appears (the last two digits of the flashing code).


Fault code: - 14 -



Proceed with key >
Further errors are displayed (if they exist):

2 : Idle contact

Short to ground
present

If key 1 is pressed instead of key > the corresponding error-code
display appears (the last two digits of the flashing code).


Fault code: - 12 -


After the last displayed error, the following instruction appears:

Repair fault accord-
ing to repair
instructions
Continue:



>

Proceed with key >

Fault repaired ?
1 = yes
3 = no


Return to display "No. of errors" with key 3.
Proceed with key 1:

Fault memory
1 = Erase
3 = Do not erase


If key 3 is pressed:
= Return to menu "error memory".
The error memory is not erased!

Proceed with key 1:

Fault memory
has been cleared

Return:



N

The test scope "Read-out error memory" is terminated
at this point.

3.2 Actuator diagnosis
If an actuator is selecled, this is triggered by the ECU so that it can
be checked for correct functioning.
The various actuators components are gone through one after
the other and are selected with the > key.
Operate the Systemtester 9288 as described under 3.1 until
the following menu display appears:

     Menu
1 = Fault memory
2 = Drive links
3 = Input signals



>

After pressing key 2, the display for the first actuator appears:

Injector
to activate
1 = Start
Continue:



>

If key > is pressed, the next actuator is selected.
Pressing key 1 results in the following instruction:

Can injectors be
heard / felt?
1 = yes
3 = no

03 - 36 Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
944 Self-diagnosis 03

Key 1 selects the next actuator (e. g. idle actuator). Following
instruction:

Repair fault accord-
ing to repair
instructions
Continue:



>

After pressing key > , the following display appears:
Injector
to activate
1 = Start
Continue:



>

Proceed with key 1
Can injectors be
heard / felt?
1 = yes
3 = no

Proceed with key 1 to the next actuator.
Idle stabilizer
to activate
1 = Start
Continue:



>

Proceed with key 1
Can idle stabilizer
be heard / felt?
1 = yes
3 = no

By pressing key 1, the next actuator is selected. After pressing
key 3, the next instruction appears:

Repair fault accord-
ing to repair
instructions
Continue:



>

Proceed with key >
Idle stabilizer
to activate
1 = Start
Continue:



>

After pressing key 1. the following display appears:

Can idle stabilizer
be heard / felt?
1 = yes
3 = no

By pressing key 1. the next actuator is selected. The actuators are
selected one after the other and triggered until the following
display appears:

Drive link test
completed

Return:



N
By pressing the key N. the operator is returned to the menu.


3.3 Circuit inputs

In addition lo the actuators, the Systemtester 9288 can also
check circuit inputs. To this end, operate the Systemtester 9288
in accordance with 3.1 until this menu display appears:

Menu
1 = Fault memory
2 = Drive links
3 = Input signals



>

Press key 3

Idle contact
1 = Start

Continue:



>

By pressing key > the next circuit input is selected.
The next display appears when key 1 is pressed.

Activate accl. pedal
Idle contact
- closed -
Continue:



>

Operate the accelerator pedal, the following display appears:

Activate accl. pedal
Idle contact
- open -
Continue:



>

The next circuit input is selected by pressing key >. Repeat until
this display appears:

Input signals
testing compleled

Return:



N

Press key N for return to menu


3.4 System adaptation

When the function "System adaplation" is triggered. the ECU re-
gisters the basic air requirement of the engine.
To this end. operate the Systemtester 9288 as per 3.1 until the
following menu display appears:

Menu
1 = Fault memory
2 = Drive links
3 = Input signals



>

Proceed with key >

< Menu
1 = System adaptation



Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
03 - 37
03 Self-diagnosis 944



Proceed with key 1

Prerequisite:
Eng. at oper. temp.
with all consumers
and ignition off.

Proceed with key >

System adaptation
1 = Start

Return:



N

If key N is pressed
= return to menu.
If key 1 is pressed:


Start engine !


Following engine start there appears:

System is being
adapted

Please wait !

Atter approx. 30 secs there appears:

System adaptation
completed

Return:



N

If it is impossible to carry out system adaptation (idle contact not
closed, or delective). the following display appears:

No system adapta-
tion possible
Idle contact ?
Return:



N

Atter cornpletion of the system adaptation, return to the menu
with key N.


3.5 Engine-knock registration

The engine-knock registration function can only be triggered
through the EZK or DME control unit.
To this end, operate the Systemtester 9288 as described in 3.1
until the following display appears:

Installed systems
1 = # LH
2 = # EZK
3 =    RDK
The particular system can be selected by means of key 1, 2 or 3.
For instance with key 2 the folIowing display appears:

    EZK
System: E01EZK
Ser. No.: 92861812415
RB. No.: 0227400154

Proceed with key >
The following menu display appears:

< Menu
1 = Fault memory
2 = Knock registration


Proceed with key 2

Condition:
Engine at operating
temperature



>

Proceed with key >

< Start knock
registration before
test drive



>

Proceed with key >

< A normal test
drive is a pre-
requisite



>

Proceed with key >

< Stop the test
drive only if the
display with the no.
of knocks comes on.

Proeeed with key >

Knock registration
1 = Start

Return:



N

Pressing key 1 activates the engine-knock counter:

Knoek registration
in progress

Please wait !


03 - 38 Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
944 Self-diagnosis 03



The knock counter registers 10,000 ignitions before the display
with the actual number of combustion "knocks" appears.

Number
Knocks:
Combustion:
Continue:

xxx
xxxxx
>

Proceed with key >

Knock registration
completed

Return:



N

If knock registration is impossible (due to lack of engine-speed
signal), the following display appears:

No knock regist-
ration possible.
RPM signal?
Return:



N

Following completion of the knock registration test, return to the
menu with key N.

3.6 Help menu

The "Help" menu can be selected from every display by pressing
key H. Return to the initial display with key N.

    Help menu
1 = Illumination
2 = Display stored
3 = Ctrl. unit chart



>

Proceed, for instance with key 1:

Key 1:
The scale illumination is switched on and the tester returns to the
previous display.

Or with key 2:
Data display stored
1 = Print
2 = Clear


Proceed with key 1
Stored displays ara printed out (If printer connected).
Proceed with key 2
Stored displays are erased.

With the "Help" menu, for instance
    Help menu
1 = Illumination
2 = Display stored
3 = Crtl. unit chart



>

If the key > is pressed, a further section of the "Help" menu is
displayed:
< Help menu
1 = Printer setting
2 = Switch of! equip.
3 = Baud Rate

Proceed for instance with key 1

Printer setting
1 = IBM
2 = HP Quiet Jet
3 = EPSON

The selection of the printer results in the tester being set up for
the printer type in question.

3.7 Store measurement displays (Key )

Using key , all displays can be stored manually.
The following displays are stored automatically:
- ECU-Identity
- Installed systems
- All existing errors
When the memory limit is reached, the following instruction
is displayed:

Data display mem.
full !

Return:



N

3.8 Show stored measurement displays (Key )

Using the keys < or >, the stored displays for the selected
system can be shown.
The stored displays can be called up by means of the key.
The system selection (LH - EZK - RDK) takes place with the keys
1, 2 or 3.

4. Service and wear parts (BOSCH)
Fig. BOSCH Part No. Designation Comment
1/3
4/1
4/2
4/3
1 687 335 002
1 684 483 152
1 684 485 170
1 680 552 005
1 684 465 193

1 684 465 194
NC- battery
Plug
Socket
Screwed cap
Printer cable
(Standard D25)
Printer cable
(EPSON)


9 pole

4.1 Service parts (Porsche)
Designation Porsche Part No. Special tool No.
Systemtester 9288
Adapter cable
Battery charger
Module (D)
Module (GB/USA)
Module (F)
Module (I)
Module (E)
000.721.928.80
000.721.928.81
000.721.928.82
000.721.928.84
000.721.928.85
000.721.928.86
000.721.928.87
000.721.928.88
9288
9288/1
9288/2
9288/4
9288/5
9288/6
9288/7
9288/8



Operating instructions for System Tester 9288
Printed in Germany - XXIV, 1991
03 - 39
10   944




















































10 - 0100 Blank page
 
944 Engine, Crankcase 10



Tightening torques for engine (16-valve)
Location Thread Tightening torque Nm (ftlb)
Crankshaft/
crankcase


Upper and lower
crankcase sections
(studs)





Knock sensor




Cylinder head

Cylinder head to upper
crankcase section
Engine type M 44.40


Engine type M 44.41
(3.0 l)


Camshaft bearing to
cylinder head

Allen screws for chain
tensioner

Banjo bolt /
Chain tensioner

Cover for cylinder head      

Fastening /
Hall sensor





M 12 x 1.5           


M 10

M 8
M 6

M 8








M 12


M 12



M 8


M 6


M 8 x 1


M 6

M 6



30(22)
60 torque angle

20(15)
50(37)
1 st stage
2nd stage

1 st stage
2nd stage
20(15)
10(7.5)

20(15) original screw
without washer





refer to Page 15 - 110
20(15)
90 torque angle
90 torque angle

20(15)
60 torque angle
90 torque angle
1 st stage
2nd stage
3nd stage

1 st stage
2nd stage
3nd stage

20(15)


10(7.5)


10(7.5)


10(7.5)

10(7.5)




Tightening torques for engine (16-valve)
Printed in Germany - XIX, 1989
01 - 0101
10 Engine, Crankcase 944



Tolerances and wear limits

Engine M 44.40/41




Cooling system


Coolant thermostat

Cooling system cap
Pressure valve

Vacuum valve

Oil circuit

Oil consumption

Oil pressure
at 80 C oil temperature:
at 5,000 rpm
Oil capacity
Difference of quantity between
dipstick marks

Valve timing

Camshaft bore


Camshaft


Camshaft


Bucket tappet bore


Bucket tappets


Camshaft




Opening temperature


opens at excess pressure

opens at vacuum



l/600 miles



excess pressure
6 l, from MY '88





Inner dia.


Dia.


Axial clearance


Inner dia.


dia.


Runout
For installing
(new)

Wear
limit


81-85 C


1.3...1.5

0.1 bar



approx. 1.5



approx. 4 bar
6.5 l


approx. 1.5 l


28 + 0.021
      - 0

28 - 0.04
      - 0.055

0.08...0.18


35 - 0.025
      - 0.041

35 - 0.025
      - 0.041

0.02





10 - 0102 Tolerances and wear limits
Printed in Germany - XXIV, 1991
944 Engine, Crankcase 10


Tolerances and wear limits

Engine M 44.40/41




Cylinder head with valves


Mating surface

Valve seat width
Exhaust
Seating angle
Outer correction angle
Inner correction angle

Valve guides:
Valve stem:
Intake
Exhaust
Valve guide/valve stem
Intake
Exhaust
Compression



Pistons with connecting rods

Cylinders/pistons


Piston rings M 44/40


Piston rings M 44/41



Piston rings M 44/40



Piston rings M 44/41




Distortion

Intake:





Inner dia.

Dia.
Dia.
Rocking clearance








Clearance


Height clearance 


Height clearance
Groove 1
Groove 2
Groove 3
Groove 1
Groove 2
Groove 3

Ring gap clearance 



Ring gap clearance
Groove 1
Groove 2
Groove 3

Groove 1
Groove 2
Groove 3

For installing    
(new)





1.5
1.8
45
30
60

7 + 0.015

6.97 - 0.012
6.94 - 0.012



8 bar and
above




0.008-0.032


0.040...0.075
0.020...0.055
0.020...0.055
0.040...0.075
0.030...0.065
0.020...0.055

0.20...0.40
0.20...0.45
0.30...0.60

0.20...0.50
0.20...0.55
0.30...0.90
Wear
limit



max. 0.05












0.8
0.8
6.5 bar





approx.
0.080




Tolerances and wear limits
Printed in Germany - XXIV, 1991
10 - 0103
10 Engine, Crankcase 944



Tolerances and wear limits

Engine M 44.40/41





Con rod bush


Piston pin
Con rod bush/piston pin



Crankshaft and cylinder block

Crankshaft
measure at bearing 2, 3 or 4
Bearing 1 and 5 on prisms
Con rod journal
Con rod/crankshaft


Crankshaft beanng journal
Crankshafts/
crankshaft
Crankshaft bearing/
crankshaft
Cylinder bore
Bore for balance shaft bearing
sheIIs at crankcase or
balance shaft cover
Bore for bushing in
bearing housing
Balance shaft



Dia.


Dia.
Radial clearance          





Runout


Dia.
Radial clearance
Axial clearance

Dia.

Radial clearance

Axial clearance
Out-of-round


Dia.

Dia.
Dia.
For installing    
(new)


24 + 0.018
     + 0.028

24-0.004
0.018-0.032





0.046


51.971-51.990
0.027-0.069
0.080...0.240

69.971-69.990

0.028-0.070

0.060...0.192
0.010


34.000...34.019

34.000...34.019
30.975...30.991
Wear
limit












max. 0.06








0.16

0,40
0,020













10 - 0104 Tolerances and wear limits
Printed in Germany - XXIV, 1991
944 Engine/Crankcase 10



REMOVING AND INSTALlING ENGINE (16-VALVE ENGINES)

TOOLS















No. Description Special Tool Remarks
  Engine suspension
beam

           3033
(VW Special Tool)
In conjunction
with workshop
crane, e.g
Bilstein K750 H.

Note:

If necessary, use a commercially available carabiner (load-bearing capacity
650 kg) to connect engine suspension beam to workshop crane.



Printed in Germany - XIII, 1987 Removing and Installing Engine 10 - 101
10 Engine/Crankcase 944



REMOVING AND INSTALLING ENGINE (MANUAL TRANSMISSION)

Remove by lowering engine from car.
The bell housing remains attached
to the engine.

Removing

1.  Align lifting platform pads
beneath jacking points and raise
car.

2. Place protective covers on
fenders.

3. Unbolt and remove front wheels.

4. Disconnect battery/bodywork
ground lead. Disconnect battery
positive lead. Disconnect wire
harness and push both cables with
rubber grommets through splash
wall. Open cable clips.

5. Unbolt panel in passenger-side
footwell and remove. Unbolt
carrier plate for DME control
unit and disconnect control-unit
plug. Disconnect 8-pin connector.



     




6.  Slacken hose clamp for fuel
return line and disconnect hose.
Disconnect fuel feed while
countering. Detach cable from
tempostat serve motor. Disconnect
series resistor/injection nozzle
connector.






10 - 102 Removing and Installing Engine Printed in Germany
944 Engine/Crankcase 10



7.  Disconnect breather hose for
toothed helt cover at rear of
lower section of air filter.
Unbolt filter assembly as a unit
and remove.



8.  Remove air-flow sensor.




9.  Slacken and remove
ignition-distributor cap and
rotor. (Mark installation
position of rotor). Remove oil
filter and ATF reservoir.
     
10.  Remove throttle valve actuating
cable complete with reversing
roller and holder. Disconnect
oxygen sensor plug connector.
Slacken hose clamps at intake
manifold and brake booster and
disconnect hoses.




11.  Remove cable clips from
bulkhead. Disconnect two-pin and
multi-pin connectors. Disconnect
vacuum hose from tank breather
valve.







Printed in Germany - XIII, 1987 Removing and Installing Engine 10 - 103
10 Engine/Crankcase 944



12. Remove engine underguard.




13.  Open coolant drain plug and
catch coolant in a suitable
container. Disconnect alternator
breather hose.

14. Disconnect coolant hose at
bottom right of radiator from
engine and remove. Catch any
coolant which may be left.

15. Disconnect electric leads from
fan motors, detach fan-motor
bracket from radiator and remove
by lowering from car.

16. Slacken coolant hose and
breather hose from top left of
radiator and remove. Disconnect
electrical connection from
temperature switch to radiator.
Disconnect coolant hose from
expansion tank and remove.
     

17.  Disconnect radiator at brackets
and remove radiator by lowering
from car.

18. Attach support beam 10-222 A to
front transport bracket of
engine and hold engine in
installation position. Check
that beam is correctly attached.










10 - 104 Removing and Installing Engine Printed in Germany
944 Engine/Crankcase 10



19.  Detach Poly-rib belt tensioner
from air-conditioning compressor
and remove belt. Remove
compresor from bracket and place
to one side. (Do not disconnect
refrigerant hoses).




20.  Unbolt stabilizer with bracket
from body and from control arms
and remove. Disengage left and
right tie rods.

21. Slacken hose clamps between ATF
cooler and steering and
disconnect line.

     
22.  Disconnect servo pump from
bracket, moving spacer sleeve
forward to remove. Leave servo
pump hanging from steering.

23. Disconnect left and right
control arms from front-axle
traverse and rear bearings and
pull forward to remove. (Do not
slacken bolts in bearing bracket).




24.  Unbolt universal joint from
steering detach hydraulic motor
mount from engine supports and
lower front-axle cross member
complete with steering and servo
pump from car.




Printed in Germany - XIII, 1987 Removing and Installing Engine 10 - 105
10 Engine/Crankcase 944



25.  Disconnect leads from starting
motor and remove starting motor.

26. Remove clutch actuating cylinder
from bell housing. (Leave line
connected). Unbolt and remove
holder for line from upper
crankcase half.

27. Disconnect exhaust from flange of
exhaust manifold and disconnect
exhaust extraction line. Remove
oxygen-sensor cable from bodywork.



28.  Disconnect flange downstream of
catalytic converter and suspension and
remove system.

29. Remove upper transaxle/bell
housing mounting bolts.

30. Disconnect coolant hoses for
heating above exhaust manifold
and from cylinder head.
     
31.  Attach VW Special Tool 3033
suspension beam to transport
bracket of engine as follows:

Pulley end:
Flywheel end: 
Position 2
Position 12

In position 2, the threaded rod is
beneath" the suspension beam. In
position 12, the threaded rod is
"above" the beam.




32.  Tighten workshop crane e.g.
Bilstein K750 H slightly to take
part af engine weight and remove
support beam 10 - 222A.

Note:

Threaded rod af support beam
10 - 222A remains in front
suspension eye.

33.  Remove lower transaxle/bell
housing mounting bolts.









10 - 106 Removing and Installing Engine Printed in Germany
944 Engine/Crankcase 10


34.  Pull engine forward, push rubber
sleeve out of firewall toward
engine compartment and carefully            
pull wire harness out of
passenger-side footwell.

35. Separate engine from central
tube/central shaft and lower
from car.


Installing

Note the following:

1.  Carefully feed wire harness for
DME control unit, 8-pin connector
and multi-pin connector into
passenger-side footwell.

2. Begin by screwing transaxle/bell
housing mounting bolts into
place, but do not tighten.


Note:

Do not tighten mounting bolts fully
until hydraulic motor bearing has
been attached to the front-axle
cross member. Tightening torque of
mounting bolts: 42 Nm (31 ftlb).

3.  Install control arms, pressing
sleeve in rubber-metal bearing
down slightly to facilitate
installation.
     


4.  Place a 4mm thick steel washer in
each of the threaded connections
between the right-hand engine
support (viewed in the forward
direction of travel) and the
hydraulic motor bearing.

5. Check that the radiator is
correctly seated on the rubber
mounts.

6. Tighten nuts and bolts to the
specified torques.

Tightening torques:

Stablizer to
aluminium control arm

25 Nm (18 ftlb)
Track rod to
steering knuckle
(locknut)

50 Nm (37 ftlb)
Steering -
universal joint

30 + 5 Nm (22 +
3.6 ftlb)
Control arm to
cross member

65 Nm (48 ftlb)
Cross member
to body
85 Nm (53 ftlb)





Printed in Germany - XIII, 1987 Removing and Installing Engine 10 - 107
10 Engine/Crankcase 944



7.  Refill system with coolant and
bleed system.




8.  Fill reservoir with ATF and bleed
steering system.

9. Run engine until it reaches
operating temperature, check
engine-oil level and coolant
level, top up if necessary.
























10 - 108 Removing and Installing Engine Printed in Germany
944 Engine/Crankshaft, Pistons 13


PISTONS. '87 MODELS ONWARD






     




(16-VALVE ENGINES)

Engine M 44.40 worldwide
Compression: 10.9 : 1
Nominal dia. 100.00 mm

An arrow pointing toward the belt
pulley indicates the installation
position.


     
1 - 

2 -
3 -
Plain compression ring.
chrome-plated
Oil scraper ring
Three-part oil wiper ring









Printed in Germany - XIII, 1987 Notes on Assembly, Pistons,
'87 Models Onward
13 - 101
13 Engine/Crankcase, Pistons 944



Checking pistons and cylinder bores

Motortype M 44.40



Repair Stage Piston Ø
(mm)
Fa. Kolbenschmidt
Cylinder bore dia.
(mm)
tolerance group
code
Standard size 99.980
99.990 +- 0.007
100.000
100.000
100.010 +- 0.005
100.020
0
1
2
Oversize 1 100.480
100.490 +-0,007
100.500
100.500
100.510 +- 0.005
100.520
I     0
I     1
I     2


Checking pistons

Measure approx. 61 mm from piston crown,
90 offset from piston pin axis.
Checking cylinder bores

Measure approx. 61 mm from upper edge of
cylinder bore, transverse to engine block.
Mount lower crankcase section and tighten
bolts to specified torque for measuring.

Note

It recommended that the stocks of the relevant tolerance group are checked befare machining
the cylinders. If necessary, hone to the piston size available.
In some cases, certain tolerance groups may be in short supply.



















13 - 102 Checking pistons and cylinder bores
Printed in Germany - XXV, 1992
944 Engine/Crankshaft, Pistons 13


Pistons from Model 89 onwards



Engine M 44. 41 (3.0 I) worldwide
Compression ratio: 10.9 : 1
Nominal Ø 104.00 mm

The installation position is indicated by the
enlarged intake-valve pockets.

171/13

Checking pistons and cylinder bore
Engine type M 44.41 (3.0 l)

Repair size Piston Ø
(mm)
MAHLE
Cylinder bore
(mm)
Tolerance groups
Code
Standard 103.980
103.990 +- 0.007
104.000
104.000
104.010 +- 0.005
104.020
0
1
2
Oversize 1 104.480
104.490 +- 0.007
104.500
1 04.500
104.510 +- 0.005
104.520
I     0
I     1
I     2

Checking pistons

Measure approx. 52 mm from crown of pis-
ton, 90' offset to axis of piston bolt.
Checking cylinder bore

Measure approx. 52 mm from top edge of
cylinder bore, across cylinder block.
For measurement, mount lower crankcase
section and tighten with prescribed tightening torque.
Note

It is recommended that the stocks of the relevant tolerance group are checked before machining
the cylinders. If necessary, hone to the piston size available.
In some cases, certain tolerance groups may be in short supply.


Pistons from Model 89 onwards
Printed in Germany - XXV, 1992
13 - 103
13   944


























This page are missing or blank in the book !


























13 - 104   Blank
944 Engine/Crankshaft, Pistons 13



Assemble cover of centrifugal oil
compartment in upper crankcase
section.


Notes on installation
Model 89 onward,
Engine type M 44.41 (3.0 l)


Note

Under normal conditions. it is not necessary
to remove the cover when overhauling an
engine. If the cover is removed, however, the
bolt area must be heated with a hot-air blower
under all circumstances. Apply Loctite 270 to
hexagon head screws.

Observe coding on the cover.


88/342





Assemble cover of centrifugal oil compartment
Printed in Germany - XIX, 1989
13 - 105
15   944




















































15 - 100   Blank page
944 Engine/Cylinder 15


























This page are missing or blank in the book !


























Printed in Germany Unknow page
15 - 101
15 Engine/Cylinder 944


























This page are missing or blank in the book !


























15 - 102 Unknow page Printed in Germany
944 Engine/Cylinder Head, Valves 15



Adjusting with dial gages


2.  Align dial gage with improvised
extension (205 mm long) on piston
crown {cylinder 1). 3 mm
pretension.
Align second gage with hydraulic
tappet of cylinder 1 intake
valve. The dial gage must be
aligned perpendicular to the
intake valve. 3 mm pretension.



3.  Remove distributor rotor and lock
camshaft sprocket with 3
M 5 x 15, to prevent camshaft
sprocket or camshaft turning when
camshaft central bolt is
slackened.
     

4.  Slacken camshaft central bolt -
note that it is essential to
counter. Slacken temporary
retaining bolts. Turn engine in
direction opposite to direction
of rotation until camshaft
sprocket reaches stop inside
feather-key groove



5.  Tighten temporary retaining bolts
(6 Nm, 4.4 ftlb) and central bolt
(approx. 40 Nm, 30 ftlb).






Printed in Germany - XIII, 1987 Checking an Adjusting
Camshaft Settings
15 - 103
15 Engine/Cylinder Head, Valves 944




6.   Turn the engine in the direction
of rotation until piston reaches
its upper limit af travel.

7. Set dial gage af cylinder 1
intake-valve hydraulic tappet to 0.

8. Turn crankshaft past ignition TDC
(cylinder 1) while observing
cylinder 1 intake-valve dial
gage. Turn engine until gage
shows 1.4 +- 0.1 mm lift.

Note:

Do not turn engine in direction
opposite to direction of rotation.

9. Slacken central bolt and
temporary retaining bolts; while
doing so, ensure that the reading
of 1.4 + 0.1 mm an the dial gage
is not changed.

10.  Now turn crankshaft slowly until
dial gage shows that piston
has reached the upper limit of
travel. With the crankshaft in
this position, the camshafts are
at ignition TDC for
cylinder 4.


     

11.  Tighten temporary retaining
bolts and central bolt.
Tightening torque of central
bolt: 65 - 70 Nm (48 - 52 ftlb).

12. Recheck by turning crankshaft
through another 2 turns and
checking setting.

13. Remove temporary retaining bolts
and install distributor rotor.





15 - 104 Checking an Adjusting
Camshaft Settings
Printed in Germany
944 Engine/Cylinder Head and Valve Drive 15




Checking or adjusting camshaft setting for Model 89 onward

Engine type M 44.41 (3.0 l)


Note

The timing has changed with installation of
new camshafts for engine type M 44.41 (3.0 l)
for Model 89 onward.



Setting

Inlet valve cylinder 1
Testing and adjusting value 0.75 +- 0.1 mm

The camshaft is adjusted according to the
same procedure as described on Page
15 - 102.




























Checking or adjusting camshaft setting f. Model 89 onward
Printed in Germany - XIX, 1989
15 - 104a
15 Engine/Cylinder Head, Valve Drive 944




Applying the TDC mark on the camshaft sprocket

Engine type M 44.40 / 41 (3.0 l)


Note

Camshaft sprockets available from the spare
parts department do not have a TDC mark.
This TDC mark is applied after the camshaft
timing has been set on the new engine.

1.   Position the new camshaft sprocket over the
old sprocket and transfer the TDC mark to
the new sprocket using a color pencil.

2. Fit new camshaft sprocket and adjust
camshaft timing as described in the Repair
Manual, page 15-102 to 104.

3. After operation 12, page 15-104, has been
carried out, engrave the TDC mark in its
final position on the new camshaft sprocket
using a three-square-file as described on
page 15-102, Fig. 1.
























15 - 104b Applying the TDC mark on the camshaft sprocket
Printed in Germany - XXIV, 1991
944 Engine/Cylinder Head, Valves 15



TOOLS - REMOVING AND INSTALLING CAMSHAFTS AND CYLINDER HEAD,
DEGREES-OF-TURN METHOD OF TORQUING (16-VALVE ENGINES)




No. Description Special Tool Remarks
1  


2


3


4
Assembly bridges for
installing camshafts

Pressure piece for
sealing ring

Assembly drift for
sealing ring

Angle reader
9248


9234


9233
In conjunction with
clamping bolt from
Special Tool 9226







Commercially available
e.g. Stahlwille No. 715/20



Printed in Germany - XIII, 1987 Tools - Removing and Installing
Camshafts and Cylinder Head
15 - 105
15 Engine/Cylinder Head, Valves 944


REMOVING AND INSTALLING CAMSHAFTS
AND CYLINDER HEAD

Removing:

1.   Align lifting-platform pads beneath
jacking points and raise car.

2. Place protective covers on
fenders.

3. Disconnect ground lead from
battery

4. Disconnect breather hose for
toothed-belt cover from rear of
lower section of air filter. Detach
entire filter assembly and remove.



5.   Remove air-flow sensor and
disconnect support (M 8 bolt)
from intake manifold.

         
6.   Remove throttle-valve actuating
able complete with reversing
roller and holder. Remove oil
dipstick. Slacken hose clamps at
intake manifold, brake booster
and breather hose and remove.







7.   Remove cover of fuel-distribution
pipe. Slacken hose clamp for fuel
return line and disconnect hose.
Disconnect fuel feed while
countering.



15 - 106 Removing and Installing
Camshafts and Cylinder Head
Printed in Germany
944 Engine/Cylinder Head, Valves 15



8.   Disconnect vacuum hose,
fuel-line-pressure damper
and fuel-distribution pipe
from intake manifold,
disconnect plug from idle
actuator, remove fuel rail with
injection valves and place to one
side.



9. Disconnect throttle-valve switch
connector. Unbolt intake manifold
from cylinder head and remove.

10. Remove engine underguard. Open
coolant drain plug and catch
coolant in suitable container.

11.  Detach exhaust at
exhaust-manifold flange.

     
12.  Pull off spark-plug caps and
remove distributor cap. Slacken
hose clamp at ATF reservoir.

13. Unbolt and remove upper and
lower toothed-belt covers,
front camshaft sprocket bracket
and cylinder-head cover.

14. Turn engine in direction of
rotation until cylinder 1
ignition TDC is reached.





Printed in Germany - XIII, 1987 Removing and Installing
Camshafts and Cylinder Head
    15 - 107
15 Engine/Cylinder Head, Valves 944



15.  Relieve tension of camshaft
toothed belt by slackening nut
A and bolt B, pressing
toothed-belt tensioner against
the pressure of the spring with
Special Tool 9200 and removing
toothed belt from camshaft
sprocket.




     
16.  Remove distributor rotor. Insert
3 temporary retaining bolts
M 5 x 20 to hold camshaft
sprocket to avoid upsetting
basic camshaft setting when
camshaft central bolt is
slackened.



17.  Slacken central bolt while
countering. Remove camshaft
sprocket.

18. Remove rear bracket.

19. Unbolt and remove chain
tensioner.

Note:

Chain-tensioner plunger is spring
loaded. When removing. compress
plunger and after removal hold in
this position with a piece of wire
or a retaining clamp.











15 - 108 Removing and Installing
Camshafts and Cylinder Head
Printed in Germany
944 Engine/Cylinder Head and Valve Drive 15



20.  Remove bearing cover from cylinders
1 + 3.

Hold both camshafts in the bearings with
Special Tool 9226. Undo and remove front
double bearing bridge and bearing cover.




87 - 422


Note

The rear double bearing bridge may remain
on the cylinder head.

21.  Undo Special Tool evenly, remove both
camshafts with chain and lay together on
one side.

22. Undo cylinder head. Undo in sequence:
from outside to inside.

23. Remove cylinder head.
      Note

If oil has been mixed with water, the cylinder
head must be subjected to a thorough visual
inspection (hairline fractures). At the same
time, check the coating system for leaks. Use
test unit VW 1274 above the expansion tank
for the teak test (max. 1 bar). The camshaft
cover must be removed for visual inspection.











Checking or adjusting camshaft sitting f. Model 89 onward
Printed in Germany - XIX, 1989
15 - 109
15 Engine/Cylinder Head and Valve Drive 944



Installing and tightening the cylinder head


Model 87 onward
Engine type M 44.40


Note


The cylinder head may be mounted with the
engine installed.

1.   Place the cylinder head gasket in the cer-
rect position.

2. Mount cylinder head
Tightening sequence:



87/420

Opposite to undoing sequence.

Tightening specifications for cylinder head
Model 87 onward
Engine type M 44.40


1st stage
2nd stage
3rd stage
               20 Nm
90 torque angle
90 torque angle
      Model 89 onward
Engine type M 44.41 (3.0 I)


Note


The cylinder head has been reinforced by 20
mm in the area of the bearing surfaces for the
cylinder head nuts. This has altered the
tightening sequence.

Tightening specifications
Model 89 onward
Engine type M 44.41 (3.0 l)


1st stage
2nd stage
3rd stage
               20 Nm
60 torque angle
90 torque angle

Note

Never use lubricant when fitting cylinder head
nuts and washers. Apply a light film of engine
oil to the stud thread only.






15 - 110 Installing and tightening the cylinder head
Printed in Germany - XXV, 1992
944 Engine/Cylinder Head, Valve Drive 15



Installing camshafts

1.   Turn engine in direction of rotation by ap-
prox. 45 before ignition TDC (cylinder 1).

2. Lay intake shaft and exhaust camshaft in
the timing chain.

3. Place both camshafts in the timing chain so
that the cast lugs are alignedwith the
marked links of the chain. Oil the bearing
jounals and place in the bearings carefully
together with the timing chain.

Note

The distance between the marking on the
intake camshaft and the markingon the
exhaust camshaft amounts to 7 outer chain
links; the distance betweenthe cast lugs
measures approx. 113 mm.



11838
     
4.   Fasten the camshafts to the cylinder head
with assembly bridges SpecialTool 9248
together with the clamping bolt of Special
Tool 9226.



87/422

5.   Install the bearing bridges and bearing
cover af the camshaft. The bearingbridges
and cover are production-matched to the
cylinder head and must alwaysbe installed
as a set. Note the identification code and
pairing number.
Tightening torque for bearing bridges and
cover 20 Nm.



11804





Installing camshafts
Printed in Germany - XVII, 1988
15 - 111
15 Engine/Cylinder Head, Valve Drive 944





11639

6.   Apply Loctite 574 to the sealing surfaces of
the front and rear double bearing bridges.

7. Use the assembly drift, Special Tool 9233
and pressure piece 9234 to drive the sealing
ring into position at the drive end of the
camshaft. Lubricate the sealing lip before
assembly.




11794
      Note

The timing chain must always be replaced if
the valves have beendamaged by the piston
as a result of a broken toothed belt.
A thorough visual inspection must be made
of the sprockets and chain tensioner.










15 - 112 Installing camshafts
Printed in Germany - XVII, 1988
944 Engine/Cylinder Head, Valve Drive 15



Installing Camshaft Seal

1.   Place sealing washers in bearings and
install bearing bridge with Loctite 574.
Tightening torque 20 Nm (15 ftlb).




87/465

2.   After torquing the bearing bridge, install
sealing cover with the aid af Special Tool
9234




86/925
       Engine installed

Note:


If the sealing cover af an engine leaks with
the engine installed, the procedure for
installing the cover is as follows:

1.   Place camshafts and sealing washers in
bearing.

2. Apply Loctite 574 to bearing bridge and
install. Place a 0.20 mm feeler gauge
between bearing bridge and cylinder head
and tighten botts slightly by hand.




928/01

3.   Apply a light film af oil to sealing cover and
press an by hand. Tighten bearing bridge
to 20 Nm (15 ftlb).








Installing Camshafts Seal
Printed in Germany - XVII, 1988
15 - 112a
15 Engine/Cylinder Head and Valve Drive 944



Camshaft specifications       Worldwide, Model 87 onward Worldwide, Model 89 onward
Engine type


Camshafts

Inlet shaft
Exhaust shaft

Identification code
On the rear
face

Timing
1 mm stroke, zero play

Inlet opens
Inlet closes
Exhaust opens
Exhaust closes
944 S
M 44.40



944.105.277.04
944.105.275.04

           277.04
275.04





4 CS
40 CS
36 CS
4 CS
     atter TDC
atter BDC
before BDC
before TDC
944 S 2
M 44.41 (3,0 l)



944.105.277.07
944.105.275.09

           277.07
275.09





3 CS
47 CS
39 CS
7 CS
     atter TDC
atter BDC
before BDC
before TDC



























15 - 112b Camshafts specifikations
Printed in Germany - XIX, 1989
944 Engine/Cylinder Head, Valves 15



REMOVING AND INSTALLING CHAIN
TENSIONER

Removing

Remove hollow screws from cylinder
head and chain tensioner and
remove complete with oil line and
seals.


Note:

Chain-tensioner plunger is
spring-loaded. When removing,
compress plunger and hold in this
position with suitable retainer
(improvised tool).


Installing

1.   Chain tensioner can be installed
without removal of retaining
clamp.

2. The retaining clamp for the
chain-tensioner plunger must be
removed once the chain tensioner
is installed.


      
3.   When installing the oil delivery
line, install a sealing ring at
both ends of the two hollow
bolts. The check valve is in the
chain tensioner housing.
Tightening torque of hollow
bolts: 10 Nm (7 ftlb)







Printed in Germany - XIII, 1987 Removing and Installing
Chain Tensioner
    15 - 113
15   944


























This page are missing or blank in the book !


























15 - 114   Blank page
944 Engine/Cylinder Head, Valves 15



TOOLS - CYLINDER HEAD (16-VALVE ENGINES)

   


 

No. Description Special Tool Remarks
1


2


3
Puller for valve stem
seals

Press-in tool for valve
stem seals

Valve spring assembly tool
9237


9225/1


9242






Or US 1020
+ US 1020/1



Printed in Germany - XIII, 1987 Tools - Cylinder Head     15 - 115
15  Engine/Cylinder Head, Valves 944



DISASSEMBLING AND ASSEMBLING CYLINDER HEAD (16-VALVE ENGINES)









15 - 116     Disassembling and Assembling Cylinder Head Printed in Germany
944 Engine/Cylinder Head, Valves 15




No. Description Qty. Note When:
Removing Installing
  1


  2


  3

  4


  5


  6


  7






  8


  9


10
Hydraulic
valve tappet

Conical valve
keeper

Spring plate

Valve spring
set

Valve spring
support

Washer


Valve stem seal






Intake valve


Exhaust valve


Valve guide
16


32


16

16


16


  X


16






  8


  8


16
Withdraw with a magnet,
do not mix up












Note number
Oil


Check correct
seating









Redetermine if
necessary

Always replace,
drive in with
press-in tool,
Special Tool
9225/1, oil sealing
lip, use drift

Oil valve stem


Oil valve stem













Printed in Germany - XIII, 1987
Disassembling and Assembling
Cylinder Head
    15 - 117
15 Engine/Cylinder Head, Valve Drive 944


Cylinder Head (16 Valves)

Removing and installing valve springs

Tools

87/927

No. Description Special tool                  Remarks
1

2

3

4

5

6
Assembly bridge

Lever arm

Magnetic removal head

Assembly head

Spacer

Screws
  Supplier: Sauer Hamburg

Supplier: Sauer Hamburg

Supplier: Sauer Hamburg

Supplier: Sauer Hamburg

Supplier: Sauer Hamburg

Commercially available M 8 x 40

Note
If the cylinder head is installed, the lever arm must be angled more accutely.



15 - 118 Removing and installing valve springs
Printed in Germany - XVII, 1988
944 Engine/Cylinder Head, Valve Drive 15



Notes on assembly

Remove and install the valve springs with
the special tool supplied by Sauer


1.   Mount the assembly bridge on the cylinder
head. Secure the cylinderhead to the work
bench with a screw clamp to prevent tilting.

2. Fasten the magnetic removal head to the
lever arm. Press the valve springstogether
in the cylinder head and loosen the
conical valve keeper from the valve shaft
with a small screwdriver.



87/926


3.   All valve spring components can be pulled
out with the magnetic removal head.

4. Fasten the assembly head to the lever
arm. Prags the tensioningarms toget her
and place the conical valve keepers in
the asssembly head.
      

87/926

5.   Place washer, valve spring support. valve
springs and spring plate in the cylinder
head and prags together with the assembly
head. A small up and down movement of
the lever arm allows the conical valve-
keepers to lock into place. This movement
also positions the conicalvalve keepers
automatically in the correct location.



87/925

6.   When the conical valve keepers are locked
in, the tensioning arms of the assembly
head point outwards.





Removing and installing valve springs
Printed in Germany - XVII, 1988
15 - 119
15 Engine/Cylinder Head, Valves 944



Remachining cylinder-head maling face

Checking cylinder head for distortion


Use a feeler gage an a straight edge or a
precision straight edge to check the maling
face of the cylinder head for distortion.

Permissible maling-face uneveness: 0.05 mm

Cylinder heads with distorted maling faces
can be remachined and reused. Permissible
rough atter finishing: 0.03 mm.

Remachining cylinder head

Do not remove mor material from the cylinder
head maling face than is necessary to
achieve a smooth surface. Max. machining
depth 146.6 mm.

Note on machining maling face:
Peak-to-valley = 0.015 mm

If the new-dimension tolerance is exceeded
during machining, a cylinder head gasket
with a thickness of 1.4 mm must be fitted.

Size new
Size worn  
= 147 +- 0.1 mm
= 146.6 mm




1126-15
       Cylinder head refacing dimension and
identification


New dimension
Gasket
Identification

Refacing dimension    
Gasket
Identification
: 147 +- 0.1 mm
: 1.1 mm
: none

: 146.8 to 146.6 mm
: 1.4 mm
: N

Identification "N"

To be embossed on exhaust side, between
cylinders no. 2 and 3, on the casting lug below
the sealing face of the cylinder head cover.

Punch character height "N" = 6 mm




15 - 120 Remachining cylinder-heat mating face
Printed in Germany - XXV, 1992
944 Engine/Cylinder Head, Valves   15


NOTES ON ASSEMBLY

REMOVING AND INSTALLING VALVE
SPRINGS

Cylinder head removed

Remove and install valve springs
with US 1020 + US 1020/1.


REMOVING AND INSTALLING VALVE
SPRINGS

Cylinder head installed

Remove and install valve springs
with Special Tool 9242.


       REMOVING VALVE STEM SEAL




Remove valve stem seal with Special
Tool 9237.






Printed in Germany - XIII, 1987
Removing and Installing
Valve Springs
Remove Valve Stem Seal
     15 - 121
15 Engine/Cylinder Head, Valves 944



INSTALLING VALVE STEM SEAL

Note:

Always remember to place an 1 mm
thick washer on the cylinder-head
face before installing the valve
stem seal.

      
1.   Lubricate valve stem and install
shaft. Place an 1 mm thick washer
on cylinder-head face. Push drift
over valve stem. Lubricate
sealing lip of valve stem seal
and position on drift. Using
Special Tool 9225/1, carefully
and gently push seal as far as it
will go onto valve guide.

2. The valve stem seal is correctly
seated when Special Tool 9225/1
and washer make contact.


Note:

The assembly drifts are available
as spare parts.














15 - 122 Installing Valve Stem Seal Printed in Germany
944 Engine/Cylinder Head, Valve Drive 15



Checking the valve guides

1.   Clean the valve guides thoroughly.

2. Use a new valve to measure the tilt play.

3. Mount bar gate holder VW 387 on the
cylinder head. The dial gaugemust be
aligned parallel to the valve disk.



15/2
      

15/3


4.   The tilt play is measured with 10 mm valve
stroke (distance betweenthe valve disk and
valve seat). Wear limit for intake and
exhaust guides = 0.80 mm.















Checking the valve guides
Printed in Germany - XVII, 1988
15 - 123
15   944




















































15 - 124 Blank page
944 Engine/Cylinder Head, Valve Drive 15



Replacing valve guides

Tools



  


87/918


No. Description Special tool Remarks
1

2

3

4
Ejection base

Plunger

Plunger

Reamer






3120
See drawing

See drawing

See drawing

VW special tool





Replacing valve guides
Printed in Germany - XVII, 1988
15 - 125
15 Engine/Cylinder Head, Valve Drive 944



Drawing
Plunger to press out the valve guide





15 - 126 Replacing valve guides
Printed in Germany - XVII, 1988
944 Engine/Cylinder Head, Valve Drive 15



Drawing
Plunger to press out the valve guide
       Plunger to press in the valve guide

                      


Replacing valve guides
Printed in Germany - XVII, 1988
15 - 127
15 Engine, Cylinder Head, Valve Drive 944



Replacing the valve guides

1.   Clean and inspect the cylinder head. It is
inexpedient to replace the valve guides in
cylinder heads where remachining is no
longer possible on the valve seats or
sealing areas.

2. Lay the cylinder head on the ejection base.

3. Press out the valve guides from the
camshaft side to the combustionchamber
side with a press.




87/921

4.   Measure the bores in cylinder with an
internat measuring caliper.

     

87/919

5.   Machine the SP valve guide Part No. 944
104 327 51 (outer diameter 11.26 mm)
accordingly.
The pressing must amount to 0.06 - 0.8 mm
for intake and exhaust valve guides

Example

Bore in the cylinder head measures
11.020 mm. Machine the outside diameter of
the SP valve guide accordingly to 11.080 or
11.10 mm.

Note

A 1 mm thick washer must always be placed
on cylinder-head face before installing the
valve guide.

6.   Heat the cylinder head up to 170 C (338
F). Apply a film of tallow tothe valve guides.
Position with a light knock, align and. from
the camshaftside, press into the cylinder
head as far as the stop with aplunger.

Attention

The temperature of 170 C (338 F). must only be maintainedfor a maximum of 90 minutes.





15 - 128 Replacing the valve guides
Printed in Germany - XVII, 1988
944 Engine, Cylinder Head, Valve Drive 15



7.   Ream the valve guides with
Special Tool 3120

Proceed as follows:

The valve guides must always be reamed with
"petroleum" lubricant Withdraw the reamer
regularly to remove chips. Then finish-ream
the boreagain with a dry reamer.





87/920

8.   The valve seat rings must be remachined
alter replacing the valve guides. It is not
enough to grind in the valves with grinding
paste


















Replacing the valve guides
Printed in Germany - XVII, 1988
15 - 129
15 Engine, Cylinder Head, Valve Drive 944



Checking the valve seat wear limit

1.  The valve seats in the 4-valve cylinder
heads can be remachined. At the same
time, the wear limit dimension must not
be exceeded as this would mean that the
hydraulic valve tappets may no longer
function correctly.

Wear dimension Intake valve Exhaust valve
As from Model 87 44.4 mm 43.4 mm


2.  This is measured with the valve to be
installed, from the end of the valve shaft to
the contact area af the valve spring support
in the cylinder head.




11841

3.  The valve must be held firmly on the valve seat for measurement.











15 - 130 Checking the valve seat wear limit
Printed in Germany - XVII, 1988
944 Engine, Cylinder Head, Valve Drive 15



Checking and remachining valve seats

Visuel inspection


1.  Check that the valve seat sits securely in the
cylinder head.

2. Check the contact pattern. If the valve does make contact over the emire surface of the valve seat. remiII the seat slighdy.

Remachining

1.  Valve seats can be remachined, for example. with the Neway valve milleror the Hunger valve seat tuming tool.

2. Remachine the valve seats with a 45 seat milling cutter. Then machine the seat to the prescribed width with a 60 correction millingcutter. A 30 correction milling cutter is not required.

Intake seat width 1.5 mm

Exhaust seat width  1.8 mm



 


1/05
      3. Valve seat milling cutter. e.g.

Neway   234 45
Neway   213 60




        



11862




11865









Checking and remachining valve seats
Printed in Germany - XVII, 1988
15 - 131
15 Engine, Cylinder Head, Valve Drive 944






11864

4.  Valve seat turning tool, e.g. Hunger VDSNL
1/45 I.K.



85/151

5.  After milling, grind in the valve seats lightly
with grinding paste. Check the contact
pattern af the valve seat surface.
      Valve dimensions





15/127





Valve dimensions 944 S


As from Model 87


Engine type M 44.40

Dimension Intake Exhaust
a

b

c

37 mm

6.97 mm

114.7 mm

45
33 mm

6.94 mm

113.7 mm

45










15 - 132 Checking and remachining valve seats
Printed in Germany - XVII, 1988
944 Engine, Cylinder Head and Valve Drive 15



Checking and adjusting installation
length of valve springs


Valve springs, Model 87 onward
Engine type M 44.40


Note

When selecting the valve-spring seat (own
construetion) always ensure that the valve-
spring seat is 2.0 + 0.2 mm thick.






1/03


Tool (own construetion)

Valve spring Sp No. 944.105.467.03

Auxiliary spring Sp No. 928.107.171.01

1.  Machine a recess of approx. 10 mm width
into valve-spring seat. Only install valve-
spring seat for measurement.
     
2. Shorten the auxiliary spring to approx.
50 mm to ease assembly.




86/927

3.  Install valve and hold in valve seat. Insert
washer. valve-spring seat, auxiliary spring
and valve-spring seat with machined recess.

4: Use Special Tool 9242 to fit the conical
valve keepers.
















Checking and adjusting installation length of valve springs
Printed in Germany - XIX, 1989
15 - 133
15 Engine, Cylinder Head and Valve Drive 944



5.  Using a depth gauge, measure from the top surface of the valve-spring seat, vertically downwards through the recess to the outer spring contact surface.




86/930


Installation length


Inlet valve
Exhaust valve
38.0 + 0.5 mm
37.0 + 0.5 mm



6.  The installation length can be adjusted
using shims.

7. The valves must not be mixed up again
after measurement.
      Valve spring, Model 89 onward
Engine type M 44.41 (3.0 l)

Note


A new type of valve spring has been installed
in engine type M 44.41 (3.0 l) from Model 89
onward. The installation length remains unchanged.

Installation lengths

Inlet valve
Exhaust valve
38.0 + 0.5 mm
37.0 + 0.5 mm

Carry out working procedure Checking and
adjusting installation length of valve springs

as described on Page 15 - 133.














15 - 134 Checking and adjusting installation length of valve springs
Printed in Germany - XIX, 1989
944 Engine/Lubrication 17



CHANGING ENGINE OIL AND ENGINE OIL FILTER (16-VALVE ENGINES)

Preconditioned:

Engine at operating temperature.

1. 
Unscrew and remove oil filler cap.

2. Unscrew oil drain plug from oil pan and drain engine oil.



  


3.  Remove oil filter with oil-filter wrench, Special Tool 9204. Catch remaining oil.
     





4.  Clean drain plug and never forget to replace seal. Tightening torque: 50 Nm (37 ftlb).


5. Lightly oil gasket of oil filter, screw in by hand until gasket makes contact, and turn through one further turn to tighten. To ensure that filter is correctly seated, recheck with oil-filter wrench. Tightening torque (for guidance): 20 Nm (14 ftlb).


6. Pour in engine oil, run ergine to operating temperature and check for leaks.


7. Check oil level with engine switched off.











Printed in Germany - XIII, 1987 Changing Engine Oil
and Engine Oil Filter
      17 - 101
17 Engine, Lubrication 944



Removing and installing the pressure reducing valve

Engine type M44.40



80/17

1 - 
2 -
3 -
4 -


Se screw
Pressure reducing valve
O-ring
O-ring


1. Remove the cylinder head cover and undo
the set screw by 2 rums.

2. Ease the pressure reducing valve out of
the seat with a screwdriverand take out
upwards.

3. Replace the O-rings and apply a light film
of oil before installation.

4. Tighten the set screw carefully until you
can feel the stop, then tum back by 45.
The screw must not be loose.
(Microencapsulated, renew if necessary).










17 - 102 Removing and installing the pressure reducing valve
Printed in Germany - XVII, 1988
944 Engine/Cooling 19



MIXING TABLE FOR COOLANT

(Average values)


Antifreeze
effective to
Antifreeze Agent Water Antifreeze Agent Water
- 25 C
- 30 C
- 35 C
40%
45%
50%
60%
55%
50%
3.1 l
3.5 l
3.9 l
4.7 l
4.3 l
3.9 l

CHECKING HEATING AND COOLING SYSTEM
FOR LEAKS (16-VALVE ENGINES)


1.  Visual inspection for leaks.

2. Check routing of cooling and
heating hoses, look for signs of
porosity, swelling, cracks and
rubbing. Replace damaged hoses.

3. Retighten hose clamps.



        





















Printed in Germany - XIII, 1987 Checking Cooling and Heating
System for Leaks
19 - 101
20 944




















































20 - 100 Blank Page
944 Fuel Supply 20




REPLACING FUEL FILTER (16-VALVE ENGINES)


1.  Disconnect fuel lines, always counter when slackening threaded connectors. Catch fuel exiting from lines in a suitable container.


2. Slacken retaining clamp and remove fuel filter.





3.  Install new filter. Direction of flow is as indicated by the arrow.



      CHECKING FUEL AND INJECTION LINES FOR LEAKS AND LOOSE CONNECTIONS


1.  Visual inspection for leaks.


2. Retighten union nuts and hose clamp.




















Printed in Germany - XIII, 1987 Replacing Fuel Filter, Checking
Injection Lines for Leaks and
Loose Connections
20 - 101
20 Fuel Supply 944




CHECKING DELIVERY RATE OF FUEL PUMP

Precondition:

Fuel filter and power supply OK.


1.  Unbolt fuel return hose from pressure regulator. Connect a length of commercially available fuel hose and place one end in a graduated cylinder (capacity apprax. 1500 cc).



2.  Disconnect DME relay from central electrics and, using a length of wire, jumper terminals 30 and 87 b.



      Allow fuel to flow into graduated cylinder for 30 seconds. Minimum delivery rate is 850 cc/30s, if necessary replace fuel pump.







20 - 102 Checking Delivery Rate of Fuel Pump Printed in Germany
944 Fuel Supply 20



FUEL SYSTEM LINE ROUTING (16-VALVE ENGINES)

'87 MODELS ONWARD

ENGINE TYPE M 44.40




1   Fuel pump
2  Fuel filter
3  Fuel collector tube
4  Pressure damper
5  Pressure regulator
A  Air flow sensor
B  Throttle valve housing
C  Intake tube
D  Idle actuator
E   Intake jet pump
F  Electric tank breather valve
a  from fuel tank
b  to fuel tank
c  from activated charcoal canister
d  to brake unit




Printed in Germany - XIII, 1987 Fuel System Line Routing
(16-Valve Engines)
20 - 103
24 944




















































24 - 100 Blank Page
944 L-Jetronic Fuel Injection 24




REPLACING AIR FILTER ELEMENT
(16-VALVE ENGINES)




1.  Use a screwdriver to remove
mounting screws and remove
upper part of air filter.



3.  Remove filter element and
clean inside of lower half of
air-filter housing with a
lint-free cloth

4. Insert filter element, place
housing cover in position and
tighten mounting screws. Check
that upper part of air filter
is correctly seated.


      CHECKING INTAKE AIR GUIDE AND
CRANKCASE BREATHER HOSES FOR LEAKS
AND LOOSE CONNECTIONS


1.  Check all hoses of intake system
for loose connections

2. Retighten hose clamps.













Printed in Germany - XIII, 1987 Replacing Air Filter Element,
Checking intake Air Guide Hoses
24 - 101
24 Air Flow Controlled Fuelinjection 944



Testing and adjusting specifications

Model 87 onward
Engine type M 44.40/41 (3.0 I)


Test Specifikation Remarks  
Electric fuel
pump
Min. delivery

rate 850 cm3/30 s
   
Fuel pressure
(engine stationary)
DEE relay jumpered


3.8 +- 0.2 bar
   
Checking value at
idle

approx. 3.3 +- 0.2 bar
   
Leak test
min. pressure after
20 Min.


2.0 bar
   
Idle speed

rpm



CO values %


ppm
without catalytic
converter
840 +- 40 **



0.5...1.5


<= 300
with
catalytic converte
840 +- 40 **



0.4...1.2 *


<= 300 *

**  Idle speed
can only now be
checked. Idle adjust-
ment no longer applies.

Measured upstream at
catalytic converter and
Lambda HC value
probe connector not
separated
CO adjustment no
longer applies.


Note

Carry out working procedure checking delivery rate of fuel pump and checking fuel
pressure
as described an Pages 20 - 102 and 24 - 103 respectively.
Tightening torque for cap nut 12 Nm.






24 - 102 Testing and adjusting specifications
Printed in Germany - XIX, 1989
944 L-Jetronic Fuel Injection 24



CHECKING FUEL PRESSURE

TOOLS

                     

No. Description Special Tool Remarks
  Pressure gage with hose
from pressure tester
P 378 or VW 1318



Printed in Germany - XIII, 1987 Checking Fuel Pressure 24 - 103
24 L-Jetronic Fuel Injection 944




CHECKING FUEL PRESSURE

1.  Slacken and remove capped nut on
test connection of fuel
distribution line.


Note:

Be careful that sealing ball does
not fall out when capped nut is
removed.

2.  Connect pressure gage with hose
from pressure tester P 378 or VW
1318 to test connection.





3.  Disconnect DME relay from central
electrics and jumper terminals 30
and 87 b with a length of
electric wire. Fuel pump must now
run.
     


4.  Control value:

Engine stopped 3.8 +- 0.2 bar
(DME relay jumpered)

Engine idling, approx. 3.3 bar

5. Tightening torque of capped nut:
22 Nm (16 ftlb)














24 - 104 Checking Fuel Pressure Printed in Germany
944 Air Flow Controlled Fuel Injection 24



Checking idle speed and CO-
with catalytic converter

Model 87 onward
Engine type M 44.40/41 (3.0 l)

Note

It is no longer possible to adjust idle speed or
CO on vehicles with catalytic converters. The
Lambda probe remains connected while
chekking idle speed and CO.

Checking preconditions

Engine in perfect mechanical condition. Con-
sumers must be switched off during checks.
Carry out checks as quickly as possible to
ensure that the intake paths do not heat up
thus falsifying the CO value. Ambient
temperature 15 - 35 C.

1.  Fit standard exhaust adapter to the test
connector of the catalytic converter.

Engine type M 44.40



86/463
      Engine type M 44.41 (3.0 l)




173-24

2.  Warm engine up to operating temperature.
(70 - 90 C oil temperature.) Use the oil-
temperature tester, Special TooIs 9122
and 9122/2.



85/114

3.  Do not separate the connection for the
Lambda probe. Connect CO tester and
separate speedometer according to the
manufacturer's specifications.
CO reference value 0.4...1.2%
Idle speed 840 +- 40 rpm




Checking idle speed and CO- with catalytic converter
Printed in Germany - XIX, 1989
24 - 105
24 Air Flow Controlled Fuel Injection 944



Checking idle speed and CO
without catalytic converter


Model 87 onward
Engine type M 44.40/41 (3.0 l)

Note


It is no longer possible to adjust the idle
speed. The throttle valve connector
adjustment therefore no longer applies.

Idle/CO adjustment

Adjustment preconditions

Engine in perfect mechanical conditions.
Consumers must be switched off during
adjustment work. Carry out adjustment as
quickly as possible to ensure that the intake
paths do not heat up thus falsifying the CO
value. Ambient temperature 15 - 35 C.

1.  Warm engine up to operating temperature.
(70 - 90C oii temperature). Use oil tempe-
rature tester, Special Tools 9122 and 9122/2.

2. Check CO value. If the CO value is not
within the prescribed tolerances. correct
the setting at the air-flow sensor. Remove
the sealing plug in the access bore to
the CO adjusting screw.
     
Engine type M 44.40

Standard screwdriver for 3 mm Allen screw.

Engine type M 44.41 (3.0 l)

Standard angled screwdriver for 5 mm
Allen screw.

Illustration shows engine type M 44.40



86/512

CO setting: 0.5...1.5 %
Turn to the right - richer mixture
Turn to the left - leaner mixture

Checking idle speed.

1.  Connect separate speedometer according
to manufacturer's specifications.

Idle speed 840 +- 40 rpm









24 - 106 Checking idle speed and CO- with catalytic converte
Printed in Germany - XIX, 1989
944 Air Flow Controlled Fuel Injection 24



Replacing air filter insert
Model 89 onward

Engine type M 44.41 (3.0 l)


1.  Replace front end plate. Refer to 944
Workshop Manual Page 50 - 5.

2. Undo retaining clips and remove housing
cover with filter insert.

3. Clean inside of filter housing with lint-free
cloth.

4. Install new filter insert. Observe installation
position. Arrow or TOP-OBEN marking
points towards the engine.




172 - 24















Checking idle speed and CO- with catalytic converte
Printed in Germany - XIX, 1989
24 - 107
26 944




















































26 - 100 Blank Page
944 Exhaust System 26




CHECKING TIGHTNESS OF EXHAUST SYSTEM FLANGES (16-VALVE ENGINES)

1.  Check tightness of exhaust
flanges and check entire exhaust
system for leaks.

2. Check tightness of hex nuts on
exhaust manifold/cylinder head
flange.

3. Check tightness of all flange
connectians in exhaust system,
together with oxygen sensor and
exhaust extractian tube.





4.  Check tightness af bolts in
primary muffler (catalytic
converter)/secondary muffler
flange. Check exhaust-system
hangers.

Tightening torques of nuts and
bolts:

M 8
M10
20 + 2 Nm (14 + 1.4 ftlb)
40 + 5 Nm (30 + 3.6 ftlb)







Printed in Germany - XIII, 1987
Checking Tightness of Exhaust
System Flanges
     26 - 101
28 944




















































28 - 100 Blank Page
944 Ignition System 28




EQUIPMENT TABlE

Ignition Coil

Type/Model Version Remarks
944 S 944 602 115 00
Bosch No.
0 221 118 322
Without series
resistors

Distributor (Cap)

Type/Model Version Remarks
944 S 928 602 211 01
Bosch No.
1 235 522 395
Only high-tension
distribution

Spark plugs

Type/Model Version Remarks
944 S Bosch WR 7 DC Spark gap
0.7 + 0.1 mm

Ignition trigger box

Type/Model Version Remarks
944 S 928 602 706 01
Bosch No.
0 227 100 124
 










Printed in Germany - XIII, 1987 Equipment Table 28 - 101
28 Ignition System 944






DME control unit

Type/Model Version Remarks
944 S Mod. '87 944.618.124.00
944.618.124.01
M 44.40
Spare part
944 S Mod. '88 944.618.124.01 M 44.40





Hall probe for knock sensors

Type/Model Version Remarks
944 S 944.606.170.01  





Knock sensor

Type/Model Version Remarks
944 S 944.606.145.00 Tightening torque
= 20 Nm (14 ftlb),
use specified
mounting bolt
(without washer)









28 - 102  
Printed in Germany - XXV, 1992
944 Egnition System 28



DME CONTROL UNIT CODING, 944 S, '87 MODELS ONWARD

       


1  -  944.612.525.01
2  -  928.607.421.00
3  -  928.607.422.00
4  -  944.612.522.00


1  -  Plug for characteristic-map switch
2  -  Plug for variant switch


Country Characteristic-map switch,
ter. 54
Varient switch, ter. 39
USA, rest of
world with
catalytic
converters
   
California,
Japan
  928.607.421.00
EC, without
catalytic
converters
 
928.607.422.00
Sweden   944.612.522.00
Australia 944.612.525.01  







Printed in Germany - XVII, 1988 DME Control Unit Coding,
944 S '87 Models Onward
28 - 103
28 Ignition System 944





REPLACING SPARK PLUGS, 944 S


1.  Pull off spark plug caps.


2. Unscrew spark plugs with
commercially available wrench. A
spark-plug wrench is supplied as
part of the car's toolkit.





Tightening torque: 25 - 30 Nm
(18 - 22 ftlb).


















28 - 104 Replacing Spark Plugs Printed in Germany
944 Ignition System 28



Equipment tabte 89 models onward

Engine type M 44.41 (3.0 l)

Ignition Coll


Type/Model Version Remarks
944 S 2 944 602 115 00
Bosch No.
0 221 118 322
without series resistors




Distributor (Cap)

Type/Model Version Remarks
944 S 2 928 602 211 01
Bosch No.
1 235 522 395
Only high-tension distribution




Spark plugs

Type/Model Version Remarks
944 S 2 Bosch WR 5 DC Spark gap
0,7 + 0,1 mm




Ignition trigger box

Type/Model Version Remarks
944 S 2 928 602 706 01
Bosch No.
0 227 100 124
 



Equipment table 89 models onward
Printed in Germany - XXV, 1992
28 - 105
28 Ignition System 944




DME Control unit

Type/Model Version Remarks
944 S 2 Mod. 89/90
944 S 2 Mod. 91
944.618.124.02
944.618.124.05
 





Hall probe for knock sensors

Type/Model Version Remarks
944 S 2 944.606.170.01  





Knock sensor

Type/Model Version Remarks
944 S 2 944.606.145.00 Tightening torque
= 20 Nm (14 ftlb),
use specified
mounting bolt
(without washer)















28 - 106 Equipment table 89 models onward
Printed in Germany - XXV, 1992
944 Ignition System, Diagnosis 28




Coding - DEE control unit 944 S 2, Model 89 onwards




     


86/746 B      86/733

1 - 928.607.421.00
2 - 928.607.422.00
1 - not used
2 - connector for variant switch





Country Variant switch
USA, rest of world with
catalytic convertor
 
California, Japan 928.607.421.00
Rest of world without
catalytic converter

928.607.422.00














Coding - DEE control unit 944 S 2, Model 89 onwards
Printed in Germany - XIX, 1989
28 - 107




DME-Diagnosis / Troubleshooting







Dr. Ing. h.c. F. Porsche Aktiengesellschaft
944 S/944 S2 Fuel System - Electronic Control 24/28



Test Point Description Page





1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Precautions
Important Vehicle Information
Testing Requirements
Effects of Faults (Cross Reference List)
DME Control Unit Plug Connections
Power Supply
Idle Speed Contact
Full Load Contact
Engine Temperature Sensor
Air Flow Sensor
Idle Speed Control Activation
Oxygen Regulation Stop
Oxygen Sensor
Intake Air Temperature Sensor
Knock Sensor I
Knock Sensor II
Control Unit Faulty
Hall Signal
Control Unit Faulty
DME Relays
Tank Venting Valve
Check Engine Waming Lamp
Fuel Pressure
Intake System Leaks
Ground and Plug Connections
Speed/Reference Mark Sender
Ignition and Final Stage
Fuel Injectors - Injection Control Unit
Alternator / Regulator
Leads K and L
CO and Idle Speed Test
Coding of Control Unit
Check-Engine-Lamp
2
3
4
7
8
9
10
11
12
13
14
15
16
16
17
17
18
18
18
19
19
20
21
22
22
24
25
28
29
29
30
31
32













DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 1
24/28 Fuel System - Electronic Control 944 S/944 S2



Precautions

Greater demands of modern engines on the ignition systems and a desire for freedom from maintenance had led to the introduction of electronic ignition systems in standard production some time ago already. Normally the ignition power of electronic systems (almost all makes) will be greater than that of conventional systems and evan greater power can be expected in the future. This places electronic ignition systems in a power range, where touching current carrying parts or terminats could be dangerous to lite (both primary and secondary circuits).

In conjunction with this matter we must point out that there must always be conformance with safety regulations and legislation of a pertinent country when working on or testing ignition systems. The ignition (ignition or source of power) must always be switched off when working on the ignition system.
Sample Jobs:

Connecting engine testers, for example:
timing light, dwell angle/speed tester, oscilloscope, etc..

Replacing ignition components, for example:
spark plugs, ignition coil, distributor, ignition leads, etc..

The above mentioned dangerous voltage will be present in the entire system should it be necessary to switch on the ignition for ignition tests or engine adjustments.

Consequently there is not onty danger on the various components of an ignition system (such as, for example, distributor, ignition coil, control units, ignition tackle), but also on wire harnesses, plug connections and testers.





















D 24/28 - 2 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Important Vehicle Information

Always turn off the ignition or disconnect the battery for resistance tests (if not, the tester could be destroyed).

Always disconnect the speed sender plug for compression tests (if not, there could be dangerous high tension and damaged insulation on the ignition coil, high tension distributor and ignition leads).

Never replace a specified ignition coil (see order number) with a different ignition coil.

Never connect a suppression capacitor on ignition coil terminals 1 and 15.

Never connect ignition coil terminal 1 on ground for the burglar alarm (ignition coil and control unit could be destroyed).

Never connect battery + or a test lamp on ignition coil terminal 1 (control unit could be destroyed).

Never disconnect the ignition lead between ignition coil terminal 4 and high tension distributor terminal 4 during operation.

Avoid voltage flashover from ignition coil terminal 4 to ignition coil terminals 1 and 15 (control unit could be destroyed).

To avoid destruction of the control unit, the secondary circuit of the ignition system must be suppressed with at least 4 k-ohms, whereby the original distributor rotor with 1 k-ohm suppression resistance must be installed.

Disconnect DME control unit and ignition final stage plugs only atter turning off the ignition.

Flashover or disruptive discharge in the area of the high tension distributor cap (poor insulation) could destroy the control unit.

Never disconnect the battery while the engine is running.

Mixing up battery pole connections could lead to destruction of the ignition final stage, ignition coil and DME control unit.

Outside starting of the engine with more than 16 volts or a boost battery charger is forbidden.

Always conform with accident prevention regulations when working on fuel systems.







DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 3
24/28 Fuel System - Electronic Control 944 S/944 S2



Equipnient Required for DME Tests:

-   Diagnostics tester 9288 (9268) with connecting leads

-   1 oscilloscope approved by Porsche

-   1 digital display multimeter with an internal resistance of at least 10 M-ohms

-   1 Bosch L-Jetronic test lead, Bosch No. 1684 463 093 (check read for correct polarity in plugs)

-   2 control unit plug test leads (local manufacture) fitted with 2 flat male plugs, 'N 17.457.2, in order to avoid damage on plug pins in the control unit plug while testing

-   2 adapter test leads, consisting of 4 plug connectors, N 017.483.1, soldered with 2 approx. 150 mm lang leads

-   1 three-pin test lead (e.g. VW VAG 1501)

-   2 control unit plug test leads (local manufacture) fitted with 4 flat male plugs, N 17.457.2

Test leads must always be used for testing!
     
-   All sender and ignition timing signals of Porsche models can be checked with the engine reglers recommended by Porsche. Instructions for connection of testers on a car will be different depending on the make, so that it will always be necessary to conform with the instructions supplied with a pertinent tester.

Sender Signals Which Can Be Checked With An Oscilloscope:

-   Speed sender signal

-   Injection () signals

-   Idle speed control activation signal

-   Hall sender signal

-   Ignition trigger signal to ignition final stage

-   Tank venting activation signal

as well as:

-   Reed switch signal (speedometer)

-   ABS wheel sensor signals



















D 24/28 - 4 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Diagnosable DME Control Unit

Self-diagnosis with a fault memory, with which it is possible to detect and store certain injection. ignition and knock regulating system faults, is integrated in the DME control unit of 944 S cars beginning with 1988 models.

The DME control unit has a permanent positive connection to prevent cancellation of detected and stored faults by turning off the ignition. Detected faults remain stored in the memory for at least 50 engine starts (exception: idle speed switch interruption faults).

Important!
If the DME control unit plug or battery is disconnected, the fault memory and system adaptation will be cancelled.

Tester Connections:

A 12-pin plug, which leads out of the DME wire harness in the passenger's footwell to the right above the DME control unit, is provided for diagnosing in cars since 1988 models. 9268 Flashing Code Testers can be connected on this plug.

A 19-pin plug replaces the 12-pin plug beginning with 1990 (L) models. Either a 9288 System Tester or the Flashing Code Tester (via adapter leads 9268/2) can be connected on this plug. Operation of the testers is explained in the instructions supplied with the testers.

Note:
A pertinent test point is supplemented by a corresponding fault flashing code of Tester 9268.

Example:
Test Point 2 = idle speed contact (1-12)
Second digit display:
"1" fault exists
"2" fault does not exist

The following actual engine data can be read direct in the "actual value" menu with a 9288 System Tester beginning with the version 2.0 tester module status.
    Intake air temperature
    Ignition timing
    Oxygen sensor voltage
    Version code
    Idle drive pulse duty factor
Engine temperature
Engine speed
Power supply
Air flow sensor signal
Load signal









DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 5
24/28 Fuel System - Electronic Control 944 S/944 S2



This DME 944 S Diagnosing/Troubleshooting Plan is based on the contents of the fault memory.

Paths not included in self-diagnosis can be diagnosed with conventional equipment (Test Points 17-25. see Fault List).

Troubleshooting requires that the person performing the tests

is familiar with the location of components, the function and technical interconnections of the systems being tested (model information).

can read and evaluate Porsche wiring diagrams.

knows the functions of circuits and relays, and

is capable of using testers, such as the oscilloscpe, voltmeter, ohmmeter and ammeter, as well as evaluating the test results.

Important!

A fault text in the display (Fault List and Flashing Code) does not always indicate a fault in the pertinent component, but could also concern the corresponding control unit or connecting leads (paths) between the component and control unit.

Troubleshooting on a running engine in the form of disconnection of plugs, etc. must not be carried out prior to reading the fault memory, since such action could be stored as faults in the fault memory.

9288 System Tester Information

Displayed in Tester

Fault does not exist, this could mean:

Fault not existing at time of testing (loose contact).
Remedy: visual inspection of path (connection).

Conditions, with which the fault is tested. ara not the same as the conditions, with which the fault had occurred.
Remedy: conform with conditions displayed in the tester.


Signal Not Plausible:

Signal of the monitored component does not fit in the tolerance range of the value calculated in the control unit.




D 24/28 - 6 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28


























This page are missing or blank in the book !


























DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 7
24/28 Fuel System - Electronic Control 944 S/944 S2


























This page are missing or blank in the book !


























D 24/28 - 8 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Fault, Fault Code Possible Causes, Elimination, Remarks


Test Point 1a
Power supply for
DME control unit (V)

a) Perm. pos. (B + )         Fault memory is cancelled, if there is
no B +.

Testing:

Connect a voltmeter on terminal 24 (-) and terminal 18 ( +) of the control unit plug with help of test leads.

Display: battery voltage

No display: check current flow and ground paths according to the wiring diagram.

Test Point 1b
Power supply for
DME control unit (V)
too high / too low
Fault Code 1_11

b) Power supply via DME relay

Connect a voltmeter on terminal 24 (-) and terminal 37 (+) of the control unit plug with help of test leads. Turn on ignition.

Display: battery voltage

No display: check current flow path according to the wiring diagram.



Remarks:

Cars with burglar alarm:
check power supply from ignition lock via burglar alarm control unit to terminal 86 af the DME relay according to the wiring diagram.

Cars without burglar alarm: check pin bridges on plug (provided for installation of a burglar alarm control unit).




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 9
24/28 Fuel System - Electronic Control 944 S/944 S2


Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 2:
Idle speed contact ()
Ground short

Fault Code 1_12

Check via circuit input test with 9288 System Tester or 9268 Tester.

Select test step and operate accelerator pedal.
9288 Display:     Idle speed contact made
Idle speed contact broken
9268 Display: 1332 (idle speed contact made)
0000 (idle speed contact broken)
No Display:

Pull off plug on DME control unit.

Connect ohmmeter between terminal 52 and terminal 24 with help of test leads.

Display:
Throttle valve closed
Throttle valve opened to gap of  
< 10
> 1 =

If the value of the idle speed contact is not reached in this test, the test should be repeated direct on the throttle valve switch as described below.

Pull off plug on throttle valve switch. Connect ohmmeter between terminals 1 and 2 of the throttle valve switch with help of test leads.

Display:
Throttle valve closed
Throttle valve opened to gap of  

< 10
> 1 =
  

Idle speed contact ()
Break

Fault Code 1_15
Testing same as described for ground short
(fault stored in memory as of 1991 models).

Check for correct adjustment, correcting if necessary.
Cause, for example, could be an incorrectly adjusted throttle valve switch or accelerator cable.


D 24/28 - 10 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28


Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 3
Full load contact ()
Ground short

Fault Code 1_13
Check via circuit input test with a 9288 System Tester or 9268 Tester.

Select test step and operate accelerator pedal.
9288 Display:    

9268 Display:
Full load contact broken
Full load contact made
1333 (tull load contact broken)
0000 (full load contact made)

No Display:

Connect ohmmeter on terminal 53 and terminal 24 of the disconnected DME control unit plug with help of test leads.

Display:
Throttle valve closed
Throttle valve opened about    
2/3rd of full gap


< 10

If the value of the full load contact is not reached in this test, the test should be repeated direct on the throttle valve switch as described below.

Pull off plug on throttle valve switch. Connect ohmmeter between terminal 3 and terminal 2 of the throttle valve switch with help of test leads.

Display:
Throttle valve closed
Throttle valve opened about    
2/3rd af full gap



< 10
    

Remarks:

If the full load contact fails, the control unit produces a load threshhold via the air flow sensor. Value below this load threshold same as switch broken or above load threshold same as switch made.



DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 11
24/28 Fuel System - Electronic Control 944 S/944 S2



Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 4
Engine tamp. sensor

(NTC II/)
Fault Code 1_14
Engine temperature can be read direct from the "actual value" menu with a 9288 System Tester.

No Plausible Display:

Connect ohmmeter on terminal 45 and terminal 24 of the disconnected DME control unit plug with help af test leads.

Display at:        0C =
15 - 30C =
40C =
80C =
100C =
   4.4 - 6.8 k
1.4 - 3.6 k
1.0 - 1.3 k
250 - 390
160 - 210

Test direct on the engine temperature sensor, if the values are not reached.

Note: Temperature sensor II sends information about the engine temperature to the control unit. It is used to provide a rich fuer/air mix-ture after a cold start or during warm-up.

Break ( ):

DME control unit of the 944 S selects a resistance value, which is stored in the control unit's memory and is approximately equal to that of an engine at operating temperature. There is no enrichment from a faulty NTC II when the engine is warm (emergency running program). This results in starting problems when the engine is cold (no cold start enrichment).

Short (0 ):

No engine pickup, too lean and stopping of engine in cold state. No effects in operating temperature state.

Replacement value is applicable to both types of fault!



D 24/28 - 12 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 5a:
Air flow sensor
(V/)
Fault Code 1_21
The ratio between Up (potentiometer voltage) and Uv (power supply voltage) can be read in the "actual value" menu with a 9288 System Tester.

When opening the air flow sensor plate the ratio must be about 0.0 to 1. If not:

a) Power supply voltage

Connect a voltmeter on terminal 3 and terminal 4 of the disconnected air flow sensor plug with help of test leads. Turn on ignition.

Display: 5 +- 0.3 volts

Test Point 5b: b) Voltage drop on air flow sensor plate potentiometer (V)

Take off air cleaner connecting hose. Connect pin 3 of the disconnected air flow sensor plug with air flow sensor plug terminal 3 and pin 4 with air flow sensor plug terminal 4 with help of test leads.

Connect a voltmeter on air flow sensor terminal 2 and terminal 4 (turn on ignition).

Display: approx. 250 - 260 m V

It must be possible to move the air flow sensor plate easily and without hesitation. Observe the voltmeter's display at the same time. Voltage jump of voltage drop should not be observed while the air flow sensor plate is opening or closing.

Display with air flow sensor prate in full load position:
approx. 4.60 volts.



DME - Diagnosing/Troubleshooting
Printed In Germany - XXIV, 1991
D 24/28 - 13
24/28 Fuel System - Electronic Control 944 S/944 S2



Fault, Fault Code Possible Causes, Elimination, Remarks

  Turn off ignition and reconnect plug if the voltage values have been reached.

Remarks:
Control unit produces replacement values in case of air flow sensor failure (emergency running program).
Injection signal from nominal air of the idle speed volumetric efficiency control for idle or a constant injection signal for partial load and full load ranges.


Test Point 6:
Idle speed control
(V)
Fault Code 1_22 only S2

Element Activation Menu

If pulse cannot be heard, check:

Power supply

Connect a voltmeter on terminal 2 and
ground of the disconnected idle speed
control plug.
Turn on ignition.
    
Display: battery voltage

No display:

Check power supply according to the wiring diagram.

Control signal test

The pulse duty factor in % can be read direct in the "actual value" menu with a 9288 System Tester.
Function test: Switch on electric power consumers with engine running at idle speed. The pulse duty factor must change and the idle speed must remain constant.
If not:









D 24/28 - 14 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Fault, Fault Code Possible Causes, Elimination, Remarks

  Connect two-pin DME test lead (Bosch No. 1 684 463 093) between the speed control and plug.

Connect and adjust engine tester to supplied operating instructions.

Make sure that electric lead connections do not have contact with vehicle ground (danger of short).

Displayed with the engine running:


Frequency: approx. 100 Hz.

Replace the idle speed control it the pulse cannot be heard in spite of correct power supply and received signal.

Test Point 7
Oxygen regulation
on stop

Fault Code 1_23

Oxygen regulation cannot work in its regulating range in case at disturbances in air/fuel mixture; for example: too lean because of excessive air or too rich because of a sticking fuel injector. It then moves against the stop.

Test 1:          Check CO level with the engine running and CO
tester connected (between 0.4 and 1.2 %).

too lean:   Check intake system for leaks
(Test Point 19).

too rich:   Check system pressure (Test Point 18).
Check fuel injectors for leaks (Test Point 18).




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 15
24/28 Fuel System - Electronic Control 944 S/944 S2



Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 8:
Oxygen sensor
(V)
(sensor signal)
Fault Code 1_24
Sensor signal test

Sensor voltage can be read direct in the "actual value" menu with a 9288 System Tester.

If not:
Disconnect oxygen sensor plug. Connect a digital display voltmeter on the sensor end test connection (sensor voltage signal) and ground.

Start and run engine warm so that the oxygen sensor reaches its operating temperature. A change in the voltage signal must be displayed when the mixture is richer, e.g. by accelerating.

Display on voltmeter:
approx. 150 mV - 900 mV (depending on composition of mixture)

Remarks:

If the control unit recognizes an oxygen) sensor voltage signal of more than 1 V or less than 0.1 V, the control unit will switch over to operation without oxygen sensor (short or break).

If regulation does not work and the sensor voltage signal is okay, check the coding of the control unit before replacing the control unit.

Test Point 9
Air temperature sensor
NTC I
()
Fault Code 1_25
Intake air temperature can be read direct in the "actual value" menu with a 9288 System Tester.

If not or when a non-plausible value is displayed:

Connect an ohmmeter on terminal 44 and terminal 26 of the disconnected DME control unit plug.

Display at:     0C =
15-30C =
40C =
    4.4-6.8 k
1.4-3.6 k
1-1.3 k


D 24/28 - 16 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Fault, Fault Code Possible Causes, Elimination, Remarks

  If no display: Disconnect plug on air flow sensor. Connect an ohmmeter on air flow sensor terminals 1 and 4 with help of test leads. Display: same as above.

Note: In case of a break, there will be a replacement value equal to an intake air temperature of 20 C (emergency running program).

          


Test Point 10
Knock sensor I

Fault Code 1_31

Knock sensor I: Knock signal not plausible. Check:
-  
-

-
-
Installation of knock sensor (check tightening torque and type of screw).
Wire harness and plug connections according to wiring diagram.
Reconnecting sensors eliminates contact resistance.
Whether coolant or other liquids are in area of the knock sensor.
Replace knock sensor.
Ignition timing retarded by 6 on crankshaft in case of a faulty knock sensor.


Test Point 11
Knock sensor II

Fault Code 1_32

Knock sensor II: Knock signal not plausible. Check:
-  
-

-
-
Installation of knock sensor (check tightening torque and type of screw).
Wire harness and plug connections according to wiring diagram. Reconnecting sensors eliminates contact resistance.
Whether coolant or other liquids are in area of the knock sensor.
Replace knock sensor.
Ignition timing retarded by 6" on crankshaft in case of a faulty knock sensor.




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 17
24/28 Fuel System - Electronic Control 944 S/944 S2



Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 12:
Control unit

(knock computer)
Fault Code 1_33



Ignition timing is retarded 6 in case of this fault.

Replace control unit.
Test Point 13:
Hall signal

Fault Code 1_34

Disconnect plug on cylinder head behind the camshaft drive gear and connect a three-pin adapter lead (VW 1501) inbetween to check the Hall signal. Connect oscilloscope positive and negative test leads on terminals 1 and 2 of the adapter lead. Start the engine.

This signal should be displayed when the Hall system is okay:





Ignition timing will be retarded approximately 6 in all speed ranges, if the DME control unit recognizes that the Hall signal is missing.

Protective circuit test:

Turn off ignition. Disconnect Hall plug. Start the engine. Idle speed ignition timing will adjust itself to approximately 4 before TDC (944 S). There must be a certain load signal from the air flow sensor in case of 944 S2 cars.


Test Point 14:
Control unit faulty

Fault Code 1_41

Replace control unit.






D 24/28 - 18 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Fault, Fault Code Possible Causes, Elimination, Remarks

Test Point 15:
DME relay

(fuel pump) (V)

Start the engine - fuel pump must run during engine starting.

It not:

Turn off ignition. Disconnect control unit plug. Connect terminal 3 and terminal 24 on the control unit plug with help of a test lead.
Turn on ignition - the pump must run!

It not:

Check current flow and ground paths of DME relay and fuel pump according to the wiring diagram.

    

Test Point 16:
Tank venting valve
(V)
Fault Code 1_43
(not 944 S)

Electric valve (for brake booster) will be opened more or less long depending on the engine load when an engine having operating temperature is running. The opened time is determined by a ground pulse from the control unit.

a) Activation test

Activate the tank venting valve in the "element activation" menu of the tester. It a pulse is not heard, check power supply to terminal 1 of the electromagnetic valve plug according to the wiring diagram.



b) Control signal test

Install DME test read (Bosch No. 1 684 463 093) between the electromagnetic valve and plug connection. Connect and adjust engine tester according to the supplied operating instructions.




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 19
24/28 Fuel System - Electronic Control 944 S/944 S2



Fault, Fault Code Possible Causes, Elimination, Remarks

  Tank venting valve is not activated permanently.

Test must be performed within 7 minutes after starting an engine having operating temperature (interrupt tank venting valve activation approx. 75 seconds afterward and then continue).

Start engine and accelerate. This must be displayed in the tester for an engine at operating temperature:

Signal will be wider as the air flow rate increases!

Check path according to the wiring diagram if there is no signal.

Replace control unit if necessary.


Test Point 17:
Check Engine
warning lamp

Fault Code 1_45
(California as of
1991 models)

A ground signal from control unit plug terminal 22 goes to and switches on the "Check Engine Lamp", if a component influencing emission control fails.

If the "Check Engine" warning lamp fails, this fault is stored in the fault memory.

Check by supplying ground to control unit plug terminal 22 and turning on the ignition.

Always replace a faulty display lamp with a specified lamp.








D 24/28 - 20 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Test Point 18: Fuel Pressure

Fuel collection pipe has a test connection at left front. Unscrew cap nut of the test connection.

Important! Inserted ball seal could fall out!

Connect P 378 pressure tester on the test connection. Start the engine. Vacuum on pressure regulator at idle speed:

Test pressure: 3.3 +- 0.2. bar
       Hot starting problems:

Check with the engine stopped and fuel pump running, without vacuum on the pressure regulator (this requires removing the DME relay and bridging terminals 87b and 30):

Test pressure: 3.8 +- 0.2 bar

-    Stop fuel pump. Read pressure on the pres
sure tester (specitication: 3.8 +- 0.2 bar).

- Max. permissible pressure drop on warm
engine: 0.5 bar in 30 minutes.

- It the pressure drops below the specitied
value, proceed as described below.
Build up pressure again by switching on the fuel pump briefly. Remove return pipe on the pressure regulator (fuel pump must not be switched on).




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 21
24/28 Fuel System - Electronic Control 944 S/944 S2



Test Point 19: Intake System leaks

Check all connections after the air flow sensor for leaks. Remove upper air cleaner section. Apply Special Tool 9264/4 on the air flow sensor and produce approx. 0.5 bar pressure in the intake system. Leaks will cause the pressure in the system to drop quickly.

(944 S: shut the safety pressure valve for crankcase breathing.)

Remarks:

Flashing Fault Code 1_23 (oxygen regulation on stop) is displayed in cars with oxygen regulation and very large leakage in the intake system (for example: intake pipe gasket).
       Test Point 20: Ground Connections (V)

    Ground read (2 x) from wire harness to engine block.

battery ground lead on clutch bell housing (engine ground) and on body (body ground next to battery).

Ignition final stage ground on side member at left front.

Fuel pump ground on rear lock cross wall behind the spare wheel.

Are ground connections tight and without corrosion? Loosen, clean and retighten ground connections as specified.

Caution!

Never start the engine as long as the ground lead between the body and engine is disconnected!
This would destroy the control unit immediately!.























D 24/28 - 22 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Plug Connections

Are all plugs connected correctly, not loose and not corroded?
Disconnect plugs and check whether pins and terminals of plugs are bent or corroded.

55-pin plug an DME control unit (behind floor plate in the front passenger's footwell).

14-pin plug in engine compartment next to the brake booster.

3-pin plug for reference mark/speed sender and 3-pin plug for oxygen sensor behind the intake pipe for cylinder no. 4 (first remove cover an the fuel ring-pipe).

3-pin plug an throttle valve switch.

2-pin plug on electromagnetic valve for tank venting (an brake boaster).

4-pin plug an air flow sensor.

2-pin plug an NTC II (temperature sensor is screwed in the engine block above the left compensating shaft near cylinder no. 1).

7-pin plug on ignition final stage in the engine compartment at front left.

3-pin Hall sender plug (behind the camshaft drive gear).

2-pin plug for knock sensor I (between in take pipes for cylinder no. 1 and 2).

2-pin plug for knock sensor II (between in take pipes for cylinder no. 3 and 4).
      
2-pin plugon idle speed control (between intake pipes for cylinder no. 2 and 3).

944 S2: between cylinder no. 1 and 2.

Plug for fuel injector ballast resistors (in engine compartment at rear right next to the plug for the brake pad wear indicator).

2-pin plugs on each of the four fuel injectors.

Because 944 S cars are supplied worldwide since 1987 models with only one standard control unit and said control unit is coded accordingly depending an country equipment, this coding must be checked in case of complaint.

A 2-pin or 3-pin plug leads out at the DME wire harness near the plug receptacle, in order to be able to call the different curve families.

Power is supplied to the DME control unit of a 944 S via terminal 30 (battery +) in addition to via ignition lock terminal 15.









DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 23
24/28 Fuel System - Electronic Control 944 S/944 S2



Test Point 21: Speed/Reference
Mark Sender


This test can only be performed with an oscillo-
scope. Connect and adjust a workshop oscillo-
scope according to the supplied operating
instructions for this purpose.

Connect the positive tester lead via a test lead
on control unit plug terminal 47 and negative
tester lead via a test lead on control unit plug
terminal 48.



Crank engine with the starter motor. Sinusoidal
oscillation of at least 3 volts (speed pulse) and
an applied higher amplitude (reference mark)
must be displayed on the screen.



 
If the voltage signal is too small (< 3 V), the
distance between the sender and gear ring
could be adjusted incorrectly.

Sender distance: Between gear ring and
sender: 0.8 +- 0.3 mm.
1 - Speed signal
2 - Reference mark signal





D 24/28 - 24 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



No display:

Disconnect plug of speed sender on plug plate in the engine compartment. Connect tester leads on middle and outside pins of the plug on the sender end of the plug with help of test leads (terminals 1 and 2, pin end). Start the engine. Sinusoidal oscillation must be displayed on the screen.



Speed sender plug

Remarks:

The display must remain unchanged after supplying ground to connection 3.

If not, check power flow, spacing and condition of the sender.
      Test Point 22: Ignition

a) Secondary ignition display









Adjust secondary ignition display an the oscilloscope. Connect tester leads according to the supplied operating instructions.

Note:

If a fault is displayed for all cylinders, it is in the primary or secondary circuit from the ignition coil to the distributor rotor. If a fault is displayed for one cylinder, this fault is located after the distributor rotor.

Primary resistor:
Secondary resistor:    
Term.1 + 15 = 0.4-0.6
Term.1 + 4 = 5-7.2 k





b) Spark plug connectors ()

Suppression resistor: 3 k
Visual inspection for damage or traces of burning.


c) Distributor

Distributor rotor, distributor cap: suppression resistor = each 1 k.
Visual inspection for damage, dirt or wrong location.




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 25
24/28 Fuel System - Electronic Control 944 S/944 S2



d) Ignition timing test

Ignition timing is checked with the engine at operating temperature.

Ignition timing and engine speed can be read direct in the "actual value" menu with a 9288 System Tester.

Test value: (944 S + 944 S2)

At 840 +- 40 rpm      10 +- 3
       e) Activation of high tension end
    (if ignition sparks are not triggered)


Ignition triggering signal can be simulated for fast troubleshooting of the ignition end. This requires connecting the oscilloscope term. 4 tester lead on the ignition lead betw. ignition cail and high tension distributor (term. 4).

Disconnect DME control unit plug.
Turn on ignition.

If battery voltage is new supplied intermittently to terminal 1 of the control unit with help of a test lead (e.g. control unit plug term. 18), a high tension peak must be displayed on the oscilloscope each time (ignition triggering).




If there is no signal, check:

-     Power supply to ignition final stage and ignition coil.

- Ground connection for ignition final stage (ground point on left front side member).

- Plug connections on ignition final stage, ignition coil and high tension distributor.
      
-     Components responsible for high tension (for example: ignition coil, ignition leads, spark plug connectors, etc.).

- Power flow in lead between control unit plug and ignition final stage term. 5.











D 24/28 - 26 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



f) Ignition final stage control signal test

Connect DME control unit plug.

Connect oscilloscope's positive tester lead on terminal 5 and negative tester lead on terminal 2 of the disconnected final stage plug.




Operate starter motor.
Oscilloscope should display the control signal of the DME control unit.


       Very important:

Coat the baseplate with a heat conducting paste prior to installation of the ignition final stage. Keep heat conducting paste off of painted parts.

Heat conducting paste:
Bosch No. 5 942 860 003.




1 - Final stage
2 - Baseplate









DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 27
24/28 Fuel System - Electronic Control 944 S/944 S2



Test Point 23: Fuel Injectors -
Injection Timing (V/)


Element activation menu:

If a pulse is not heard, check:

a) Power supply

Pull off injector plug. Connect voltmeter on injector plug terminal 2 and ground with help of test leads. Turn on ignition.

Display: battery voltage
If there is no dispiay:    

Disconnect 5-pin plug of fuel injector ballast resistors. Connect voltmeter between terminal 3 (terminal sleeve end) and ground.
Turn on ignition.

If battery voltage is displayed, Turn off ignition and pull off all plugs on fuel injectors. Check power flow and resistance between the S-pin plug of ballast resistors and terminal 2 of each fuel injector plug with an ohmmeter.

Resistance of each ballast resistor = 6


Check current path according to the wiring diagram if battery voltage is not displayed.
      b) Coil resistanee test of fuel injectors

Pull off injector plugs. Check coil resistance on the contacts of the fuel injectors with an ohmmeter.

Test value: 2 - 3

c) Injection final stage


Adjust oscilloscope according to the supplied operating instructions. Connect Bosch test lead (1 684 463 093) between fuel injector and plug. Connect tester leads on Bosch lead according to the supplied operating instructions.

Caution:
Tester leads must not have any contact with ground.


Start the engine. These displays must appear in the oscilloscope if the injection final stage is working perfectly and test connections are correct.

Starter speed



Remarks:

If the engine cannot be started or the idle speed drops, change tester connections on the Bosch lead and check tester adjustment.



D 24/28 - 28 DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
944 S/944 S2 Fuel System - Electronic Control 24/28



Test Point 24: Alternator, Regulator

Misfiring of the engine could be caused by the peak voltage of the alternator.

Take drive belt off of the alternator. Start the engine.

Check alternator and regulator if the disturbances have been eliminated.

Test Point 25: Leads K and L

Connections for diagnosing between the DME control unit and fasters are made with both leads K and L Check the folIowing points when diagnosing is not possible.

1. Power flow test (see wiring diagram)

Lead L: Pin 7 (19-pin diagnostics socket) - Pin 13 (DME plug)

Lead K: Pin 8 (19-pin diagnostics socket) - Pin 55 (DME plug)

2. Ground short test (see wiring diagram)

Lead L: Voltage on Pin 7 (19-pin diagnostics socket) must be > 8 V with the ignition turned on.

Lead K: Voltage on pin 8 (19-pin diagnostics socket) must be > 8 V with the ignition turned on.

Possible Causes of Fault:

-    Ground short or break in wiring or plug connections.

- Faulty control unit, which is connected on these leads (could be any diagnosable control unit; does not always have to be the DME control unit).
     
  Checking: Pull off plugs on diagnosable control units one after the other until there is
> 8 V. Replace fault-eausing control unit.

-    Tester faulty.

- Power supply lacking on diagnostics socket.

- Ground supply lacking on diagnostics socket.

Information for idle speed and idle speed CO test:

a) Idle speed

944 S engines have adaptive idle speed volumetric efficiency regulation since 1987 modeIs. This means that the idle speed of all versions does not have to be adjusted. The system of cars with adaptive idle speed volumetric efficiency regulation should be adapted each time the DME control unit had been disconnected on permanent positive or after each inspection.

Idle speed control value for engine at operating temperature:
840 +- 40 rpm

b) Idle speed CO of cars without catalytic converter

CO level is still adjusted on the CO adjusting screw in the air flow sensor.
Requirements:
-    Engine at operating temperature.

- Engine and ignition in perfect running condition.

- All electric consumers switched off.

- CO tester at operating temperature, calibrated and adjusted correctly.



DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 29
24/28 Fuel System - Electronic Control 944 S/944 S2



Adjusting value: 0.5 - 1.5 % CO
at 840 +- 40 rpm and ignition timing of
10 +- 3 before TDC.

Adapt the system after adjusting the CO level.
An adapter plug (911.612.422.8) must be con-
nected on the oxygen sensor connecting lead
of cars without a catalytic converter, in order
to avoid diffusion (see wiring diagram).

c) Idle speed CO of cars with catalytic
    converter


In addition to adaptation of the idle speed
there is also adaptation of the idle speed CO
level in these cars, so that it is only necessary
to check the actual state in such cars.
Requirements:
-    Engine at operating temperature.

- Engine and ignition in perfect running
condition.

- All electric consumers switched off.

- CO tester at operating temperature,
calibrated and adjusted correctly.

- Oxygen sensor plug connected.



Test value: 0.4 - 1.2 % CO
at 840 +- 40 rpm and ignition timing of
10 +- 3 before TOC.

Afterwards the engine must be run at least
10 minutes after disconnection of the
control unit plug or disconnection of the
battery, before it will be possible to recheck
these values. In addition, the system must
be adapted.







D 24/28 - 30 DME - Diagnosing/Troubleshooting
Printed In Germany - XXII, 1990
944 S/944 S2 Fuel System - Electronic Control 24/28



Coding of Control Unit - 944 S

Pertinent curve families are integrated in the DME control unit, in order to be able to comply with the legislation of different countries. They can be read direct in the "actual value" menu with a 9288 System Tester.


One each 2-pin and 3-pin plug, which are bridged differently depending on the country version, lead out of the DME wire harness to call these curve families.

Country Curve Family Switch
2 Pins
Version Switch
3 Pins
USA Federal States
FAG M 298
Oxygen sensor
- -
USA Califomia
Japan
Oxygen sensor
- Bridge against
battery voltage
928.607.421.00
ECE - Bridge against grd.
928.607.422.00
Sweden - Resistance
6.8 k against grd.
944.612.522.00
Australia
Oxygen sensor
Bridge against ground
944.612.515.00
-




DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989
D 24/28 - 31
24/28 Fuel System - Electronic Control 944 S/944 S2



Coding af Control Unit - 944 S 2


Country Curve Family Switch
2 Pins
Version Switch
3 Pins
All with cat. conv. - -
Califomia, Japan - Bridge against
battery +
928.607.421.00
All without cat. conv. - Bridge against grd.
928.607.422.000


As from model year '91, the code for California and Japan is being deleted (identical worldwide).




























D 24/28 - 32 DME - Diagnosing/Troubleshooting
Printed In Germany - XXII, 1990
944 S/944 S2 Fuel System - Electronic Control 24/28



Check-Engine Lamp

(Malfunction Indicator Light M.I.L)

As from model year '91, Califomian legislation prescribes a waming lamp which lights up if a part relevant to the exhaust gas fails.

As a function check of the warning lamp, it lights up when the ignition is switched on and goes out once the engine is running when this is started without depressing the accelerator.

The waming lamp has a flashing code to indicate a defective fault path.

To trigger off the flashing code, fully depress the accelerator pedal with the engine off and the ignition on for 3 seconds until the Malfunction Indicator Lamp flashes. Then remove foot from accelerator.

If no fault is recorded, i.e. no warning came from the indicator light, there appears the flashing code

      1500
no fault.


= Lamp on     o = Lamp off

If the waming light did indicate a warning, i.e. there is a fault, there appears a flashing code, e.g.


      1124
Oxygen sensor


The flashing code is listed in the Diagnosing/Troubleshooting plan on page D 24/28-7.
The fault can also be read direct using System Tester 9288. After a repair the fault memory must be erased using the System Tester.




DME - Diagnosing/Troubleshooting
Printed In Germany - XXII, 1990
D 24/28 - 33