Workshop Manuel Volume IA - Engine, 16 valves DR. ING. h. c. F. PORSCHE Aktiengesellschaft As webpage by http://www.9ss1.
944 Table of contents volume I-A Page General Technical data 0.
volume I-A Table of contents 944 Page 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 15 - 120 15 - 121 15 - 122 15 - 123 15 - 125 15 - 130 15 - 131 15 - 133 Engine - Lubrication Replacing engine oil and oil filter Pressure-reduclng valve, removing and
944 General TYPE 944 S (16-VALVE ENGINES) - '87 MODELS ONWARD Printed in Germany - XIII, 1987 Technical Data 0.
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 M 44/40 Number of cylinders 4 Bore mm/in. 100/3.94 Stroke mm/in. 78.9/3.11 Displacement (actual) cc/in.3 2479/151 10.9 : 1 Compression ratio Max. engine output to 80/1269/EC kW/PS 140/190 - 135/184 Australia Net power, SAE J 1349 kW/HP 140/188 at engine speed rpm 6000 Max.
944 General Crankcase Two-part light alloy crankcase Crankshaft Forged, 5 bearings Crankshaft bearings Plain Connecting rods Cast, opt.
General 944 Sealed cooling system, electric fan with thermoswitch, antifreeze effective to - 25°C ENGINE COOLING ENGINE LUBRICATION 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 Lubrication n = 5000 rpm Oil pressure Approx. 4 bar, at operating temperature Oil-pressure indicator Pilot lamp and pressure gage Max. oil temperature 140°C l/1000 km Oil consumption Up to 1.
944 General FUEL SYSTEM Injection DME Digital Motor Electronics Fuel delivery 1 electric fuel pump Fuel octane rating RON/MON Fuel consumption to 80/1268/EC or ECE R 15/04 Constant 90 km/h Constant 120 km/h EC exhaust urban cycle Standard: 95/85 - European standard premium unleaded possible Opt./M298: 95/85 unleaded - European standard premium Australia: 91/82 unleaded Standard: l/100 km l/100 km 6.7 8.3 l/100 km 12.
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 mm/in. 4230/165.354 Length with opt. extra US bumpers mm/in. 4290/168.90 Width mm/in. 1735/68.31 Height mm/in. 1275/50.20 Wheel base (in design pos.) mm/in. 2400/94.49 (4290/168.90) Rim size Track: Front mm/in. 1477/58.2 1477/58.2 1477/58.
944 General WEIGHTS - to DIN 700 20 - Curb weight Standard Sports package Australia, standard Front kg/lbs 640/1411 (650/1433) 630/1389 640/1411 Rear kg/lbs 640/1411 (650/1433) 610/1345 (630/1389) 640/1411 Total kg/lbs 1280/2822 1240/2734 (1260/2778) 1280/2822 Front kg/lbs 730/1609 730/1609 (720/1587) 730/1609 Rear kg/lbs 900/1984 900/1984 920/2028 Per.
General 944 CAPACITIES Engine (measurement with dipstick as per Driver's Manual is definitive) Proprietary HD oils to APl classification SE or SF, see Driver's Manual Engine oil Approx. 6.0 l Engine coolant Approx. 8.5 l Transmission with differential Approx. 2.0 l hypoid oil, SAE 80 to MIL-L 2105, APl classification GL 4 Fuel tank Approx. 80 l, including approx. 8 l reserve Brake-fluid reservoir Approx. 0.2 l Windshield and headlight washing fluid reservoir Approx. 0.
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 Manual transmission M 44.41 (3.0 I) Bore mm (in.) 104 (4.09) Stroke mm (in.) 88 (3.46) Displacement (actual) cm3(in.3) 2990 (182.5) Displacement (rounded down) cm3 2969 10.9: 1 Compression ratio Max.
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 control unit capable of diagnosis is identified by an altered part number. A specially developed diagnostic tester (special tool No.
03 Maintenance, Self-diagnosis 944 Display 03 - 2 LED off Test sequence terminated / igniti Flashing LED Error code / test code LED on Ignition on DME control unit error diagnosis Printed in Germany - XVI, 1987
944 Maintenance, Self-diagnosis Connection in the 944 S 03 Diagnosis socket in the car Pin 1 = terminal 15 In the 944 S, the diagnosis socket is attached to a separate cable harness located above the DME control unit. Pin 2 = terminal 31 Pin 5 = terminal 30 Pin 9 = Hall generator 87/1012 87/908 Ignition off After connecting the tester, the following display must appear.
03 Maintenance, Self-diagnosis Tester cable Switch on the ignition Diagnosis plug Round plug Pin 1 Pin 4 Pin 2 Pin 1 Pin 3 Pin 7 Pin 4 Pin 6 Pin 5 Pin 2 Pin 6 unused Pin 7 unused Pin 8 unused Pin 9 unused Pin 10 unused 944 Pin 11 Pin 5 Pin 12 Pin 3 Display: The ignition must not be switched off during the entire error diagnosis procedure.
944 Maintenance, Self-diagnosis 03 Starting error diagnosis If an error is displayed - take the note of the error (e.g. 1211). Condition: Engine off Ignition on Display: Display: The error is displayed until the green key is again pressed on the tester. The next error code is then displayed. if applicable. Press the green key until the clear symbol appears on the function display. This must be repeated until 1000 appears on the display. Display: If no error has occurred.
03 Maintenance, Self-diagnosis 944 Press the green key until the clear symbol appears 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).
944 Maintenance, Self-diagnosis 03 Actuator and input signal function checking Starting actuator and input signal function check 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.
03 Maintenance, Self-diagnosis Press the green key until the ctear symbol appears on the function display. This activates the first testing step and the injection valves are activated. Display: 944 The next testing step is initiated by again pressing the green key. Refer to the test code list for the sequence of testing steps. The injection valves must all operate audibly or tangibly.
944 Maintenance, Self-diagnosis As from the "idle contact" testing step, specific controls must additionally be operated on the car for the purpose of function checking. 03 Initiate the full load contact testing step. Display: 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. Slowly press the accelerator until the full throttle position is reached. The LED must go off and the display will appear after approx.
03 Maintenance, Self-diagnosis 944 Initiale the air-conditioning control terminal 41 testing step. Initiate the air-conditioning control terminal 40 testing step. Display: Display: Switch on the air-conditioning system. The LED must go off and the display will appear after approx. 3 s. Switch off the air conditioning system. The LED must go off and the display will appear after approx. 3 s.
944 Maintenance, Self-diagnosis 03 Press the green key until the clear symbol appears. Display: End of the actuator and input signal function checks.
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944 Maintenance, Self-diagnosis 03 Test code list Test code Components 1311 Injection valves 1321 Rotary idle controller 1322 Solenoid valve - tank bleeding 1332 Idle contact 1333 Full load contact 1334 Air-conditioning/AC switch 1335 Air-conditioning/compressor coupling Test code list Printed in Germany - XVI, 1987 03 - 13
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944 03 Maintenance, Self-diagnosis System adaption Display: 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. The engine must now idle for at least 30 seconds. Ignition off System adaption is then completed.
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944 Maintenance, Self-diagnosis Knock detection 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. Engine at operating temperature Knock detection should not be carried out if the customer has complained about poor output or too high a consumption, for instance.
03 Maintenance, Self-diagnosis 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: 944 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.
944 03 Maintenance, Self-diagnosis Troubleshooting Error code 1111 Diagnosis using the tester can refer only to the error path, but not to a defective component. The supply voltage is too low < 10 V or too high > 16 V. Possible causes for too low a supply voltage: Note: Battery exhausted Before troubleshooting, the entire error memory must be read out. 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.
03 Maintenance, Self-diagnosis 944 Error code 1112 Connect a ohmmeter between terminal 52 and terminal 24 on the DME plug. This error code indicates an error in the area of the idle contact. Display: Possible error: Throttle valve closed: R < 10 Ground fault Switch stuck Throttle valve open: R = Switchover must already occur if the throttle valve is only slightly open (approx. 1°).
944 Maintenance, Self-diagnosis 03 Error code 1113 Error code 1114 This error code draws attention to an error in the area of the full load contact. This error code draws attention to an error in the area of the engine temperature sensor (NTC 2). Possible errors: Ground fault Switch stuck Testing the full load contact Connect an ohmmeter between terminal 53 and terminal 24 on the DME plug.
03 Maintenance, Self-diagnosis Error code 1121 Display 0°C = 15 - 30°C = 80°C = 100°C = 944 4400 1400 250 160 - 6800 - 3600 - 390 21 This error code draws attention to an error in the area of the air-flow sensor. 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) informs the control unit about the current engine temperature.
944 Maintenance, Self-diagnosis 03 Testing the power supply of the air-flow sensor: A voltage rise must be observed during this time. Ignition on Display: 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). approx. 0.2 V - ca. 4.6 V No abrupt voltage changes must be observed during opening or closing. (Abrupt voltage changes. i.e.
03 Maintenance, Self-diagnosis 944 Error code 1123 Error code 1124 When this error code appears, the Lambda control has detected too rich ar too lean a mixture. This error code draws attention to an error in the area of the Lambda probe.
944 03 Maintenance, Self-diagnosis Error code 1125 Measure the voltage between pin 1 and engine ground. 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. 35 The voltage is within the range of approx. 150 mV - 900 mV depending on the mixture composition.
03 Maintenance, Self-diagnosis 944 Error code 1131 Error code 1132 This error code draws attention to an error in the area of knock sensor 1. This error code draws attention to an error in the area of knock sensor 2. 87/910 87/911 Error testing of the knock sensors is an active error test, i.e. error testing is carried out during driving.
944 Maintenance, Self-diagnosis 03 Error code 1133 Error code 1134 Error code 1133 draws attention to an error in the area of the knock control in the DME control unit. If this error code appears, the DME control unit must be replaced. This error code draws attention to an error in the area of the Hall generator.
03 Maintenance, Self-diagnosis 944 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. 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.
944 Maintenance, Self-diagnosis 03 Error code - List Error code Error path 1500 No error 1000 Output end 1111 Supply voltage too low/high 1112 Idle contact 1113 Full load contact 1114 NTC 2 1121 Air-flow sensor 1123 Lambda control detects a too rich / too lean mixture 1124 Lambda probe signal not correct 1125 NTC 1 1131 Knock sensor 1 1132 Knock sensor 2 1133 Knock control in the control unit 1134 Hall generator signal 1141 DME control unit A digit 2 (e.g.
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944 Maintenance, Self-diagnosis 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: 03 The error memory is reset if the LED goes off and the function display changes to 0000. Display: The yellow key must be pressed until the function symbol (see display) appears on the function display.
03 Self-diagnosis 944 Operating conditions for start of diagnosis Systems Ignition on Engine standing still Engine running 944 S / 944 S2 DME yes to n < 2000 rpm Airbag yes yes Alarm system yes yes Webdesign from www.9ss1.
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 1. General information 1.1 Application The Systemtester 9288 (BOSCH KTS 301) is a microprocessor-controlled self-diagnosis tester. All systems which have a diagnosis interface as per ISO Standard can be tested with this tester.
944 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.
03 Self-diagnosis After pressing the key > , a selection menu is displayed: Menu 1 = Fault memory 2 = Drive links 3 = Input signals > 944 After the last displayed error, the following instruction appears: Repair fault according to repair instructions Continue: > Proceed with key > < Menu 1 = System adaptation Fault repaired ? 1 = yes 3 = no In the example - press key 1. There then follows the display of the number of errors which are stored (if any). Number of faults Return to display "No.
944 03 Self-diagnosis Key 1 selects the next actuator (e. g. idle actuator). Following instruction: By pressing the key N. the operator is returned to the menu. 3.3 Circuit inputs Repair fault according to repair instructions Continue: > After pressing key > , the following display appears: Injector to activate 1 = Start Continue: In addition lo the actuators, the Systemtester 9288 can also check circuit inputs. To this end, operate the Systemtester 9288 in accordance with 3.
03 Self-diagnosis Proceed with key 1 The particular system can be selected by means of key 1, 2 or 3. For instance with key 2 the folIowing display appears: Prerequisite: Eng. at oper. temp. with all consumers and ignition off. EZK System: E01EZK Ser. No.: 92861812415 RB. No.: 0227400154 Proceed with key > Proceed with key > The following menu display appears: System adaptation 1 = Start Return: 944 N If key N is pressed = return to menu.
944 The knock counter registers 10,000 ignitions before the display with the actual number of combustion "knocks" appears. Number Knocks: Combustion: Continue: 03 Self-diagnosis xxx xxxxx > Knock registration completed N If knock registration is impossible (due to lack of engine-speed signal), the following display appears: No knock registration possible. RPM signal? Return: N Following completion of the knock registration test, return to the menu with key N. 3.
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944 10 Engine, Crankcase Tightening torques for engine (16-valve) Location Thread Tightening torque Nm (ftlb) M 12 x 1.5 30(22) 60 ° torque angle 1 st stage 2nd stage M 10 20(15) 50(37) 20(15) 10(7.5) 1 st stage 2nd stage Crankshaft/ crankcase Upper and lower crankcase sections (studs) M8 M6 Knock sensor M8 20(15) original screw without washer Cylinder head Cylinder head to upper crankcase section Engine type M 44.
10 Engine, Crankcase 944 Tolerances and wear limits Engine M 44.40/41 For installing (new) Cooling system Coolant thermostat Opening temperature 81-85° C Cooling system cap Pressure valve opens at excess pressure 1.3...1.5 Vacuum valve opens at vacuum 0.1 bar Wear limit Oil circuit Oil consumption l/600 miles Oil pressure at 80° C oil temperature: at 5,000 rpm Oil capacity Difference of quantity between dipstick marks excess pressure 6 l, from MY '88 approx. 1.5 approx. 4 bar 6.
944 10 Engine, Crankcase Tolerances and wear limits Engine M 44.40/41 For installing (new) Cylinder head with valves Mating surface Distortion Valve seat width Exhaust Seating angle Outer correction angle Inner correction angle Intake: 1.5 1.8 45° 30° 60° Valve guides: Valve stem: Intake Exhaust Valve guide/valve stem Intake Exhaust Compression Inner dia. 7 + 0.015 Dia. Dia. Rocking clearance 6.97 - 0.012 6.94 - 0.012 Wear limit max. 0.05 8 bar and above 0.8 0.8 6.
10 Engine, Crankcase 944 Tolerances and wear limits Engine M 44.40/41 For installing (new) Wear limit Con rod bush Dia. 24 + 0.018 + 0.028 Piston pin Con rod bush/piston pin Dia. Radial clearance 24-0.004 0.018-0.032 Crankshaft measure at bearing 2, 3 or 4 Bearing 1 and 5 on prisms Con rod journal Con rod/crankshaft Runout 0.046 Dia. Radial clearance Axial clearance 51.971-51.990 0.027-0.069 0.080...0.
944 10 Engine/Crankcase REMOVING AND INSTALlING ENGINE (16-VALVE ENGINES) TOOLS No. Description Engine suspension beam Special Tool Remarks 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.
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.
944 7. Disconnect breather hose for toothed helt cover at rear of lower section of air filter. Unbolt filter assembly as a unit and remove. 10 Engine/Crankcase 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. 8. Remove air-flow sensor. 11. Remove cable clips from bulkhead. Disconnect two-pin and multi-pin connectors.
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. 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.
944 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). 10 Engine/Crankcase 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). 20.
10 Engine/Crankcase 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.
944 10 Engine/Crankcase 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. 4.
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.
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. Printed in Germany - XIII, 1987 1 - Plain compression ring.
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 I I 0 1 2 Checking pistons Checking cylinder bores Measure approx. 61 mm from piston crown, 90° offset from piston pin axis. Measure approx.
944 13 Engine/Crankshaft, Pistons 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.
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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.
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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. 4. Slacken camshaft central bolt note that it is essential to counter. Slacken temporary retaining bolts.
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.
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.
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.
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 Assembly bridges for installing camshafts 9248 2 Pressure piece for sealing ring 9234 In conjunction with clamping bolt from Special Tool 9226 3 Assembly drift for sealing ring 9233 4 Angle reader Printed in Germany - XIII, 1987 Commercially available e.g. Stahlwille No.
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 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. 4.
944 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. Engine/Cylinder Head, Valves 15 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.
15 Engine/Cylinder Head, Valves 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. 944 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.
944 Engine/Cylinder Head and Valve Drive 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. 15 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).
15 Engine/Cylinder Head and Valve Drive 944 Installing and tightening the cylinder head Model 87 onward Engine type M 44.40 Model 89 onward Engine type M 44.41 (3.0 I) Note Note The cylinder head may be mounted with the engine installed. 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. 1. Place the cylinder head gasket in the cerrect position. 2.
944 Engine/Cylinder Head, Valve Drive Installing camshafts 1. Turn engine in direction of rotation by approx. 45° before ignition TDC (cylinder 1). 15 4. Fasten the camshafts to the cylinder head with assembly bridges SpecialTool 9248 together with the clamping bolt of Special Tool 9226. 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.
15 Engine/Cylinder Head, Valve Drive 944 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. 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.
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). 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.
15 Engine/Cylinder Head and Valve Drive 944 Camshaft specifications Worldwide, Model 87 onward Worldwide, Model 89 onward Engine type 944 S M 44.40 944 S 2 M 44.41 (3,0 l) 944.105.277.04 944.105.275.04 944.105.277.07 944.105.275.09 Camshafts Inlet shaft Exhaust shaft Identification code On the rear face 277.04 275.04 277.07 275.
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: 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) Chain-tensioner plunger is spring-loaded.
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944 15 Engine/Cylinder Head, Valves TOOLS - CYLINDER HEAD (16-VALVE ENGINES) No.
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 No. Description Qty.
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 Assembly bridge Supplier: Sauer Hamburg 2 Lever arm Supplier: Sauer Hamburg 3 Magnetic removal head Supplier: Sauer Hamburg 4 Assembly head Supplier: Sauer Hamburg 5 Spacer Supplier: Sauer Hamburg 6 Screws Commercially available M 8 x 40 Note If the cylinder head is installed, the lever arm must be angled more accutely.
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 5. Place washer, valve spring support.
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. Cylinder head refacing dimension and identification Permissible maling-face uneveness: 0.05 mm New dimension Gasket Identification : 147 +- 0.1 mm : 1.1 mm : none Cylinder heads with distorted maling faces can be remachined and reused.
944 15 Engine/Cylinder Head, Valves NOTES ON ASSEMBLY REMOVING AND INSTALLING VALVE SPRINGS REMOVING VALVE STEM SEAL Cylinder head removed Remove and install valve springs with US 1020 + US 1020/1. Remove valve stem seal with Special Tool 9237. REMOVING AND INSTALLING VALVE SPRINGS Cylinder head installed Remove and install valve springs with Special Tool 9242.
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.
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. 15/3 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.
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944 15 Engine/Cylinder Head, Valve Drive Replacing valve guides Tools 87/918 No.
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 Drawing Plunger to press out the valve guide Replacing valve guides Printed in Germany - XVII, 1988 15 Plunger to press in the valve guide 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. 87/919 5. Machine the SP valve guide Part No. 944 104 327 51 (outer diameter 11.26 mm) accordingly.
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.
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.
944 Engine, Cylinder Head, Valve Drive Checking and remachining valve seats 3. Valve seat milling cutter. e.g. Visuel inspection Neway 234 45° Neway 213 60° 1. Check that the valve seat sits securely in the cylinder head. 15 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. 11862 2.
15 Engine, Cylinder Head, Valve Drive 944 Valve dimensions 11864 15/127 4. Valve seat turning tool, e.g. Hunger VDSNL 1/45 I.K. Valve dimensions 944 S As from Model 87 Engine type M 44.40 85/151 5. After milling, grind in the valve seats lightly with grinding paste. Check the contact pattern af the valve seat surface. 15 - 132 Dimension Intake Exhaust a 37 mm 33 mm b 6.97 mm 6.94 mm c 114.7 mm 113.
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 valvespring seat is 2.0 + 0.2 mm thick. 2. Shorten the auxiliary spring to approx. 50 mm to ease assembly. 1/03 86/927 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.
15 Engine, Cylinder Head and Valve Drive 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. 944 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.
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. 4. Clean drain plug and never forget to replace seal. Tightening torque: 50 Nm (37 ftlb). 3. Remove oil filter with oil-filter wrench, Special Tool 9204. Catch remaining oil. 5.
17 Engine, Lubrication 944 Removing and installing the pressure reducing valve Engine type M44.40 80/17 1 - Se screw Pressure reducing valve 2 - O-ring 3 - O-ring 41. 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°.
944 19 Engine/Cooling 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.
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944 Fuel Supply 20 REPLACING FUEL FILTER (16-VALVE ENGINES) CHECKING FUEL AND INJECTION LINES FOR LEAKS AND LOOSE CONNECTIONS 1. Disconnect fuel lines, always counter when slackening threaded connectors. Catch fuel exiting from lines in a suitable container. 1. Visual inspection for leaks. 2. Retighten union nuts and hose clamp. 2. Slacken retaining clamp and remove fuel filter. 3. Install new filter. Direction of flow is as indicated by the arrow.
20 Fuel Supply 944 CHECKING DELIVERY RATE OF FUEL PUMP Precondition: Fuel filter and power supply OK. Allow fuel to flow into graduated cylinder for 30 seconds. Minimum delivery rate is 850 cc/30s, if necessary replace fuel pump. 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.
944 Fuel Supply 20 FUEL SYSTEM LINE ROUTING (16-VALVE ENGINES) '87 MODELS ONWARD ENGINE TYPE M 44.
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944 L-Jetronic Fuel Injection 24 REPLACING AIR FILTER ELEMENT (16-VALVE ENGINES) CHECKING INTAKE AIR GUIDE AND CRANKCASE BREATHER HOSES FOR LEAKS AND LOOSE CONNECTIONS 1. Use a screwdriver to remove mounting screws and remove upper part of air filter. 1. Check all hoses of intake system for loose connections 2. Retighten hose clamps. 3. Remove filter element and clean inside of lower half of air-filter housing with a lint-free cloth 4.
24 Air Flow Controlled Fuelinjection 944 Testing and adjusting specifications Model 87 onward Engine type M 44.40/41 (3.0 I) Test Specifikation Electric fuel pump Min. delivery rate 850 cm3/30 s Fuel pressure (engine stationary) DEE relay jumpered Checking value at idle Leak test min. pressure after 20 Min. Idle speed 3.8 +- 0.2 bar approx. 3.3 +- 0.2 bar 2.0 bar rpm without catalytic converter 840 +- 40 ** CO values % 0.5...1.5 ppm Remarks <= 300 with catalytic converte 840 +- 40 ** 0.4.
944 24 L-Jetronic Fuel Injection CHECKING FUEL PRESSURE TOOLS No.
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. 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) 3.
944 Air Flow Controlled Fuel Injection Checking idle speed and COwith catalytic converter 24 Engine type M 44.41 (3.0 l) 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. Consumers must be switched off during checks.
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) Engine type M 44.40 Note Standard screwdriver for 3 mm Allen screw. It is no longer possible to adjust the idle speed. The throttle valve connector adjustment therefore no longer applies. Engine type M 44.41 (3.0 l) Idle/CO adjustment Adjustment preconditions Standard angled screwdriver for 5 mm Allen screw. Illustration shows engine type M 44.
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.
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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.
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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 944 S 928 602 706 01 Bosch No.
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 944 S 944.606.170.01 Remarks Knock sensor Type/Model Version Remarks 944 S 944.606.145.
944 28 Egnition System DME CONTROL UNIT CODING, 944 S, '87 MODELS ONWARD 1 2 3 4 - 944.612.525.01 928.607.421.00 928.607.422.00 944.612.522.00 Country 1 - Plug for characteristic-map switch 2 - Plug for variant switch 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.
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).
944 28 Ignition System 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 944 S 2 928 602 706 01 Bosch No.
28 Ignition System 944 DME Control unit Type/Model Version 944 S 2 Mod. ´89/90 944 S 2 Mod. ´91 944.618.124.02 944.618.124.05 Remarks Hall probe for knock sensors Type/Model Version 944 S 2 944.606.170.01 Remarks Knock sensor Type/Model Version Remarks 944 S 2 944.606.145.
944 Ignition System, Diagnosis 28 Coding - DEE control unit 944 S 2, Model 89 onwards 86/733 86/746 B 1 - 928.607.421.00 2 - 928.607.422.00 Country 1 - not used 2 - connector for variant switch Variant switch USA, rest of world with catalytic convertor California, Japan 928.607.421.00 Rest of world without catalytic converter 928.607.422.
DME-Diagnosis / Troubleshooting Dr. Ing. h.c. F.
944 S/944 S2 24/28 Fuel System - Electronic Control Test Point 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 Description 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
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.
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.
24/28 Fuel System - Electronic Control 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) 944 S/944 S2 - All sender and ignition timing signals of Porsche models can be checked with the engine reglers recommended by Porsche.
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.
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).
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 Fault, Fault Code Fuel System - Electronic Control 24/28 Possible Causes, Elimination, Remarks Test Point a) Perm. pos. (B + ) Fault memory is cancelled, if there is 1a no B +. Power supply for DME Testing: control unit (V) 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.
24/28 Fuel System - Electronic Control Fault, Fault Code 944 S/944 S2 Possible Causes, Elimination, Remarks Test Point 2: Check via circuit input test with 9288 System Tester or 9268 Tester. Idle speed contact ( ) Ground short Select test step and operate accelerator pedal. Fault Code 1_12 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.
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.
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: 0°C = 15 - 30°C = 40°C = 80°C = 100°C = 4.4 - 6.8 k 1.4 - 3.6 k 1.0 - 1.
944 S/944 S2 Fault, Fault Code Fuel System - Electronic Control 24/28 Possible Causes, Elimination, Remarks The ratio between Up (potentiometer voltage) and Uv (power supply voltage) can Test Point 5a: be read in the "actual value" menu with a 9288 System Tester. Air flow sensor When opening the air flow sensor plate the ratio must be about 0.0 to 1.
24/28 Fuel System - Electronic Control Fault, Fault Code 944 S/944 S2 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.
944 S/944 S2 Fault, Fault Code Fuel System - Electronic Control 24/28 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.
24/28 Fuel System - Electronic Control Fault, Fault Code 944 S/944 S2 Possible Causes, Elimination, Remarks Sensor signal test Test Point 8: Oxygen sensor Sensor voltage can be read direct in the "actual value" menu with a 9288 (V) System Tester. (sensor signal) Fault Code 1_24 If not: Disconnect oxygen sensor plug. Connect a digital display voltmeter on the sensor end test connection (sensor voltage signal) and ground.
944 S/944 S2 Fuel System - Electronic Control Fault, Fault Code 24/28 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 Knock sensor I: Knock signal not plausible.
24/28 Fuel System - Electronic Control Fault, Fault Code 944 S/944 S2 Possible Causes, Elimination, Remarks Test Point Ignition timing is retarded 6° in case of this fault. 12: Control Replace control unit. unit (knock computer) Fault Code 1_33 Test Point Disconnect plug on cylinder head behind the camshaft drive gear and connect a 13: Hall signal three-pin adapter lead (VW 1501) inbetween to check the Hall signal.
944 S/944 S2 Fault, Fault Code Fuel System - Electronic Control 24/28 Possible Causes, Elimination, Remarks Test Point 15: Start the engine - fuel pump must run during engine starting. DME It not: relay (fuel pump) (V) 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.
24/28 Fuel System - Electronic Control Fault, Fault Code 944 S/944 S2 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.
944 S/944 S2 Fuel System - Electronic Control 24/28 Test Point 18: Fuel Pressure Hot starting problems: Fuel collection pipe has a test connection at left front. Unscrew cap nut of the test connection. 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): Important! Inserted ball seal could fall out! Connect P 378 pressure tester on the test connection. Start the engine.
24/28 Fuel System - Electronic Control 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.
944 S/944 S2 Fuel System - Electronic Control 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.
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 oscilloscope. Connect and adjust a workshop oscilloscope 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.
944 S/944 S2 24/28 Fuel System - Electronic Control No display: Test Point 22: Ignition 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.
24/28 Fuel System - Electronic Control 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° 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).
944 S/944 S2 Fuel System - Electronic Control 24/28 f) Ignition final stage control signal test Very important: Connect DME control unit plug. Coat the baseplate with a heat conducting paste prior to installation of the ignition final stage. Keep heat conducting paste off of painted parts. 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.
24/28 Fuel System - Electronic Control 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.
944 S/944 S2 Fuel System - Electronic Control 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 24/28 Checking: Pull off plugs on diagnosable control units one after the other until there is > 8 V. Replace fault-eausing control unit. - Tester faulty.
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 connected on the oxygen sensor connecting lead of cars without a catalytic converter, in order to avoid diffusion (see wiring diagram).
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.
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).
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.
