Porsche 944 manuel d'utilisation

Workshop Manuel Volume IA - Engine, 16 v alves DR. ING. h. c. F. PORSCHE A ktiengese llschaft As w ebpage by http://w ww .9ss1.dk/porsche944[...]

944 Table of contents v olume I-A General Technical data Maintenance, Self-diagnosis Fault diagnosis, DEE control uni t Connecting into the vehicle - 944 S Starting fault diagnosis Functional test - actuator and inp ut signal List of test codes System adaptation Knock detection Troubleshooting List of fault codes Clearing fault memory Operating con[...]

volume I-A T able of contents 944 Machining mating face, cy linder head Vaive springs, removing and install ing, removing valve stem seal Valve stem seal, installing Checking valve guides Replacing valve guides Checking valve seat wear li mit Valve seats, checking and m achinin g Checking and adjusting installation length of valve springs Engine - [...]

944 General TYPE 944 S (16-VALVE ENGINES) - '87 MODEL S ONWARD 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 pa rentheses DRIVE UNIT Internal engine designa tion Number of cylinde rs Bore Stroke Displacement (actual) Compression ratio Max. engine output to 80/1269/EC Net power, SAE J 1349 at engine speed Max. torqu[...]

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 Pla[...]

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, ele ctric fan with thermoswitch, antifreeze effective to - 25° C Forced-feed lubrication with sickle-type pump, oil filter and oil-w[...]

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[...]

General 944 BODY DESIGNS Integral all-steel body with front air da m and rear spoiler - as coupe, opt.: removabl e hardtop panel, also available with fog lamps set in PU front air dam as optional extra. DIMENSIONS (at DIN curb wei ght) Length Length with opt. extra US bumpers W idth Height W heel base (in design pos.) Track: Front Rear Ground clear[...]

944 General W EIGH TS - 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 W ith 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 k[...]

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 W indsh ield and headlight wa shing fluid reservoir Proprietary HD oils to APl classification SE or SF, see Driver's Manual Approx. 6.0 l Approx. 8.5 l Appr[...]

944 General Technical da ta - Type 94 4 52 - Model 89 (Values for adjustment and wea r are to be found in the respective repair groups) Notes: USA values are given in brackets Drive unit Internal engine designa tion Bore Stroke Displacement (actual) mm (in.) mm (in.) cm 3 (in. 3 ) Manual transmission M 44.41 (3.0 I) 104 (4.09) 88 (3.46) 2990 (182.5[...]

944 Ma intenance, Self-diagnosis 03 DME control unit error diag nosis 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-diagnosi s. That is to say, the control uni t is capable of detecting, storing and displaying system errors. The con- trol unit capable of diagnosis is [...]

03 Maintenance, Self-diagnosis 944 Display LED off Test sequence terminated / igniti Flashing LED Error code / test code LED on Ignition on 03 - 2 DME con trol unit error di agnosis Printed in Germ any - XVI, 1987[...]

944 Ma intenance, Self-diagnosis 03 Connection in the 944 S In the 944 S, the diagnosis socket is attached to a separate cable ha rness located above the DME control unit. 87/1012 Ignition off After connecting the tester, the follow ing dis- play must appear. Display: If this is not the case, check the tester ter- minals or check the pow er supply [...]

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 s witched off during the entire error diagnosis procedure. 03 - [...]

944 Ma intenance, Self-diagnosis 03 Starting error di agnosis 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 o f the error (e.g. 1211). Display: The [...]

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 diagno sis of the DME control unit. If one or several erro rs (up to 5) has/have been displayed, the error memory must be reset; see chapter (Resetting the erro r memo[...]

944 Ma intenance, Self-diagnosis 03 A ctuator and input si gnal 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 sign als with respect to their functioning or signal paths. Functions ara triggered from the diagno sis te[...]

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 va lves are activated. Display: The injection valves m ust all op erate audibly or tangibly. Note: If later attempts are made to start the engine, starting difficulties may occur b[...]

944 Ma intenance, Self-diagnosis 03 As from the "idle contact" testing step, specific controls must additionally b e operated on the car for the purpose of function checki ng. Idle contact display: Slightly press the accelerator. The LED must go off after approx. 20 mm and the di splay will appear After approx. 3 s. Display: If this is no[...]

03 Maintenance, Self-diagnosis 944 Initiale the air-conditioning control terminal 41 testing step. Display: Switch on the air-condition ing system. The LED must go off and the disp lay will appear after approx. 3 s. Display: If this is not the case, an error ha s occurred in the area of the air-conditioni ng system's wiring. In the event of an[...]

944 Ma intenance, Self-diagnosis 03 Press the green key until the clear symbol appears. Display: End of the actuator and inp ut signal function checks. Actuator and inpu t signal function checking Printed in Germ any - XVI, 1987 03 - 11[...]

03 944 03 - 12 Blank page[...]

944 Ma intenance, Self-diagnosis 03 Test code li st 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 swi tch Air-conditioning/co m pressor coupli ng Test code list Printed in Germ any - XVI, 1987 03 - 13[...]

03 944 03 - 14 Blank page[...]

944 Ma intenance, Self-diagnosis 03 System adaptio n System adaption can be carried out with the tester. That is to say. the ele ctronic 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 nece ssary for the engine to be at operating te m perature[...]

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944 Ma intenance, Self-diagnosis 03 Knock detec tion Before knock detection is carried ou t, error diagnosis must first of all be pe rform ed to guarantee that no electrical error has occurred in the area of the knock control an d the knock sensors. Knock detection should not be carried out if the customer has complai ned about poor out- put or too[...]

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 igni tions. the function display will change to "r". Display: Counting is now complete. The number af knocks is display ed in per mill. In this example. 25 knocks have occurred. Kn[...]

944 Ma intenance, Self-diagnosis 03 Troubleshootin g Diagnosis using the teste r can refer only to the error path, but not to a defectiv e component. Note: Before troubleshooting, the entire error memory must be read out. Error code 1 111 The supply voltage is too low < 10 V or too high > 16 V. Possible causes for too low a supply voltage: Ba[...]

03 Maintenance, Self-diagnosis 944 Error code 1 112 This error code indi cates an error in the area of the idle contact. Possible error: Ground fault Switch stuck Testing the idle contact Extract the plug from the DM E control unit. 32 Connect a ohmmeter betw een terminal 52 and terminal 24 on the DM E plug. Display: Throttle valve clo sed: R < [...]

944 Ma intenance, Self-diagnosis 03 Error code 1 113 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 betwee n term inal 53 and terminal 24 on the DM E plug. Display: Throttle valve clo sed: R = Throttle valve in full load p[...]

03 Maintenance, Self-diagnosis 944 Display 0° C = 15 - 30° C = 80° C = 100° C = 4400 - 1400 - 250 - 160 - 6800 3600 390 21 If the values are not reached in this testing step, measurement must be carried ou t directly on the engine temperature sensor. The engine temperature sensor (NTC 2) in- forms the control unit about the curren t engine temp[...]

944 Ma intenance, Self-diagnosis 03 Testing the power supply of the air-flow sensor: Ignition on On the extracted plug of the air-f low 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 extra[...]

03 Maintenance, Self-diagnosis 944 Error code 1 123 W hen this erro r code appears, the La mbda control has detected too rich ar too lean a mixture. Possible causes for too lean a mixture: Lambda probe ground faul t Intiltrated air on the intake side Intiltrated air on the exhaust side of the Lambda probe Injection valve does not open Ignition cut-[...]

944 Ma intenance, Self-diagnosis 03 Measure the voltage bet ween 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 ha rness t o the DME control unit with reference to the circui t diagram. Error code 1 125 This error code indi cates an error in the area of th[...]

03 Maintenance, Self-diagnosis 944 Error code 1 131 This error code draws attention to an error in the area of knock sensor 1. 87/911 Error code 1 132 This error code draws attention to an error in the area of knock sensor 2. 87/910 Error testing of the knock senso rs is an active error test, i.e. error testing is carrie d out during driving. If an[...]

944 Ma intenance, Self-diagnosis 03 Error code 1 133 Error code 1133 draws attention to an error in the area of the knock control in the DM E con- trol unit. If this error code appe ars, the DME control unit must be replaced. Error code 1 134 This error code draws attention to an error in the area of the Hall generator. 87/904 Possible errors: Grou[...]

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 dia gram. Error code 1 141 Error code[...]

944 Ma intenance, Self-diagnosis 03 Error code - Lis t 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 [...]

03 944 03 - 30 Blank page[...]

944 Ma intenance, Self-diagnosis 03 Resetting the error memory Once the DME control unit error diag nosis has been completed. this is completed by error code 1000. The error memory canno t be reset as follows until this error code appears: The yellow key m ust be presse d until the function symbol (see display) ap pears on the function display . Di[...]

03 Self-diagnosis 944 Operating con ditions for start of diag nosis 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 W ebde sign from www.9ss1.dk/porsche 944 03 - 32 Operating condit ions for start o f diagnosis Printed in Ge rmany - XX IV, 1991[...]

944 Self-diagnosis 03 Operating i nstructions for Sy stem Tester 92 88 Operating instru ctions for Syst em Tester 92 88 Printed in Germ any - XXIV, 1 991 03 - 33[...]

03 Self-diagnosis 944 1. General infor mation 1.1 Application The Syste mtester 9288 (BO SCH KT S 301) is a microprocesso r-con- trolled self-diagn osis teste r. All systems which have a diagnosis i nterface a s per ISO S tandard can be tested w ith this tester . The follow ing tests are possible: * Reading out the fault memory * Testing of th e ac[...]

944 Self-diagnosis 03 1.3 Battery ch arger run of f mains vo ltage (Fig ure 3) - Accessory - Item 1 Charg er with conn ecting cab le, 1.5 m long Item 2 8-pin AMP plug 1.4 Vehicle- specific adap ter cable Porsche No. 000 721 928 .81 1.5 Connectin g lead (Figur e 4) - Self-fabricati on - for printer, pro gramme loa d station o r similar unit . For in[...]

03 Self-diagnosis 944 After pressing the key > , a selection menu is displayed: Menu 1 = Fault memory 2 = Drive lin ks 3 = Input signal s > < Menu 1 = Syste m adaptation In the example - press key 1. There then follow s t he display of the number of errors w hich are s tored (if any ). Number of faults - 2 - Proceed w ith k ey > Additio[...]

944 Self-diagnosis 03 Key 1 selec t s the nex t actuator (e . g. idle actua t or). Follow ing instruction: Repair fault a cc ord- ing to repair instructions Continue: > After pressing key > , the follow ing dis play app ears: Injector to activate 1 = Start Continue: > Proceed w ith k ey 1 Can injectors be heard / felt? 1 = yes 3 = no Proce[...]

03 Self-diagnosis 944 Proceed w ith k ey 1 Prerequisite: Eng. at oper. temp. with all con sumers and ignition o f f. Proceed w ith k ey > System adap t ation 1 = Start Return: N If key N is pre s sed = return to menu. If key 1 is pre ss ed: Start engine ! Following engi ne start there appears: System is bei ng adapted Please w ait ! Atter approx[...]

944 Self-diagnosis 03 The knock co unter registers 10,000 ignitions bef ore the display with the actual number of combustio n "knocks" appears. Number Knocks: Combustion: Continue: xxx xxxxx > Proceed w ith k ey > Knock registra tion completed Return: N If knock regi s tration i s impossible (due to lack o f engine-speed signal), th[...]

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944 Engine, Crankcas e 10 Tightening torques for engine (16-v al ve) Location Thread T ightening 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 chai[...]

10 Engine, Crankcase 94 4 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[...]

944 Engine, Crankcas e 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 [...]

10 Engine, Crankcase 94 4 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/cranksha ft Crankshaft beanng journal Crankshafts/ crankshaft Crankshaft bearing/ crankshaft Cylinder bore Bore[...]

944 Engine/Crankca se 10 REMOVING AND INSTALlING ENGINE (16-VAL VE 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 co mm ercially available carabiner (load-bearing capacity 650 kg) to connect engine susp ension beam t[...]

10 Engine/Crankcase 944 REMOVING AND INSTALLING ENGINE (MANUAL TRANSMISSION) Remove by lowe ring engine f rom 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/bodyw ork gr[...]

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). Remov e oil filter and ATF reservoir. 10. Remove throttle valve ac[...]

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 fro m engine and remove. Catch any coolant which may be left. 15. Disconnect electric leads from fan motors, detach fan-motor brack[...]

944 Engine/Crankcase 10 19. Detach Poly-rib belt tension er from air-conditioning compressor and remove belt. Remov e compresor from bracket and pla ce to one side. (Do not disconnect refrigerant hoses). 20. Unbolt stabilizer with bracket from body and from control ar m s and remove. Disengage left and right tie rods. 21. Slacken hose cla m ps betw[...]

10 Engine/Crankcase 944 25. Disconnect leads from starting motor and remove starting m otor. 26. Remove clutch actuating cy linder 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 disconn ect exhaust extraction line. Re m ove oxygen-sen[...]

944 Engine/Crankcase 10 34. Pull engine forward , push rubber sleeve out of firewall toward engine compartment and carefully pull wire harness ou t of passenger-side footwell. 35. Separate engine from central tube/central shaft and low er from car. Installing Note the following: 1. Carefully feed wi re harness for DME control unit, 8-pin con nector[...]

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 ON W ARD (16-VALVE ENGINES) Engine M 44.40 wo rldwide Compression: 10.9 : 1 Nominal dia. 100.00 mm An arrow pointing toward the belt pulley indicates the in stallation position. 1 - 2 - 3 - Plain compression ring. chrome-plated Oil scraper ring Three- part oil wiper ring Printed in Germany [...]

13 Engine/Crankcase, Pistons 944 Checking pistons and c y linde r bores Motortype M 44.40 Repair Stage Piston Ø (mm) Fa. Kolbenschmidt Cylinder bore dia. (mm) tolerance group code Standard size 9 9.980 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 [...]

944 Engine/Crankshaft, Pistons 13 Pistons from Model 89 onwards Engine M 44. 41 (3.0 I) wo rldwide 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 cy lin der bore Engine type M 44.41 (3.0 l) Repair size Piston Ø (mm) MAHLE Cylinder bore (mm) T[...]

13 944 This page ar e missing or blank in the book ! 13 - 104 Blank[...]

944 Engine/Crankshaft, Pistons 13 A ssemble cover of centrifugal oil compartment in upper cra nkcase 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 ove rhauling an engine. If the cover is removed, how ever, the bolt area must be heated w ith a ho[...]

15 944 15 - 100 Blank page[...]

944 Engine/Cylinder 15 This page ar e missing or blank in the book ! Printed in Germany Unknow page 15 - 101[...]

15 Engine/Cylinder 944 This page ar e 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 improvi sed extension (205 mm long) on piston crown {cylinder 1). 3 mm pretension. Align second gage with hydra ulic tappet of cylinder 1 intake valve. The dial gage m ust be aligned perpendicular to the intake valve. 3 mm pretensio n. 3. Remove distribu tor roto[...]

15 Engine/Cylinder Head , Valves 944 6. Turn the engine in the directio n of rotation until piston reaches its upper limit af travel. 7. Set dial gage af cylinder 1 intake-valve hydraulic tappe t to 0. 8. Turn crankshaft past ignition TDC (cylinder 1) while obse rving cylinder 1 intake-valve dial gage. Turn engine until gage shows 1.4 +- 0.1 mm lif[...]

944 Engine/Cylinder Head and Valve Drive 15 Checking or adjusting cams haft setting for Model 89 onward Engine type M 44.41 (3.0 l) Note The timing has changed wi th installation of new camshafts for engine type M 44.41 (3.0 l) for Model 89 onwa rd. Setting Inlet valve cylinde r 1 Testing and adjusting value 0.75 +- 0.1 mm The camshaft is adjusted [...]

15 Engine/Cylinder Head, Valv e Drive 944 A ppl ying the TDC mark on the camsha ft 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 camsha ft timing has been set on the new engin e. 1. Position the new camshaft sprocket ov er the ol[...]

944 Engine/Cy linder Head, Valves 15 TOOLS - REMOVING AND INSTALLING CAMSHAFTS AND CYLINDER HEAD, DEGREES-OF-TURN M ETHOD OF TORQUING (16-VALVE ENGINES) No. Description Special Tool Remarks 1 2 3 4 Assembly bridge s for installing camshafts Pressure piece for sealing ring Assembly drift for sealing ring Angle reader 9248 9234 9233 In conjunction wi[...]

15 Engine/Cylinder Head , Valves 944 REMOVING AND INSTALLING CAMSH AFTS AND CYLINDER HEAD Removing: 1. Align lifting-platform pads bene ath jacking points and rai se 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 e[...]

944 Engine/Cylinder Head , Valves 15 8. Disconnect vacuu m hose, fuel-line-pressure da m per 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-v alve switch connector. Unbolt intake m ani fold from cylinder head and rem ove. 10. R[...]

15 Engine/Cylinder Head , Valves 944 15. Relieve tension of camsha ft toothed belt by slackening nut A and bolt B, pressing toothed-belt tensioner again st the pressure of the spring wi th Special Tool 9200 and re m oving toothed belt from camshaft sprocket. 16. Remove distribu tor rotor. I nsert 3 temporary retaining bolts M 5 x 20 to hold camshaf[...]

944 Engine/Cy linder Head and Valve Drive 15 20. Remove bearing cove r from cylinders 1 + 3. Hold both camshafts in the bearings with Special Tool 9226. Undo and rem ove f ront double bearing bridge and bea ring cover. 87 - 422 Note The rear double bearing bridge m ay re m ain on the cylinder head. 21. Undo Special Tool evenly, remove both camshaft[...]

15 Engine/Cylinder Head and Valve Drive 944 Installing and tightening the c y linder hea d Model 87 onward Engine type M 44.40 Note The cylinder head m ay be m ounted 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 sp[...]

944 Engine/Cy linder Head, Valve Drive 15 Installing camshafts 1. Turn engine in direction of rotation by ap - prox. 45° before ignition TDC (cylind er 1). 2. Lay intake shaft and exhaust ca ms haft in the timing chain. 3. Place both camshafts in the timing chain so that the cast lugs are aligne dwith the marked links of the chain. Oil the bearing[...]

15 Engine/Cylinder Head, Valv e Drive 944 11639 6. Apply Loctite 574 to the sealing surfaces of the front and rear double bea ring bridges. 7. Use the assembly drift, Spe cial Tool 9233 and pressure piece 9234 to drive the sealing ring into position at the drive en d of the camshaft. Lubricate the seali ng lip before assembly. 11794 Note The timing[...]

944 Engine/Cy linder Head, Valve Drive 15 Installing Camshaft Seal 1. Place sealing washers in bearings and install bearing bridge wit h Loctite 574. Tightening torque 20 Nm (15 ftlb). 87/465 2. After torquing the bearing brid ge, install sealing cover with the aid af Special Tool 9234 86/925 Engine installed Note: If the sealing cover af an engi n[...]

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[...]

944 Engine/Cylinder Head , Valves 15 REMOVING AND INSTALLING CHAIN TENSIONER Removing Remove hollow screws from cylinder head and chain ten sioner and remove complete with oil lin e and seals. Note: Chain-tensioner plunger is spring-loaded. W hen removi ng, compress plunger and hold in this position with suitable retainer (improvised tool ). Instal[...]

15 944 This page ar e 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 ste m seals Press-in tool for valve stem seals Valve spring asse m bly tool 9237 9225/1 9242 Or US 1020 + US 1020/1 Printed in Germany - XIII, 1987 Tools - Cylinder Head 15 - 115[...]

15 Engin e/Cylinder Head, Valves 944 DISASSEMBLING AND ASSEMBLING CY LIN DER HEAD (16-VALVE ENGINES) 15 - 116 Disassembling and Asse m bling Cylinder Head Printed in Germany[...]

944 Engine/Cylinder Head , Valves 15 Note W hen: No. Description Qty. 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 W asher Valve stem seal Intake valve Exhaust valve Valve guide 16 32 16 16 16 X 16 8 8 16 W ithdraw with a m agnet, do not mix up Note number Oi[...]

15 Engine/Cylinder Head, Valv e Drive 944 Cylinder Head (16 Valves ) Removing and installing valve springs Tools 87/927 No. Description Special tool Re marks 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[...]

944 Engine/Cy linder 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 prev ent tilting. 2. Fasten the magnetic removal head to the lever arm. Press the valve springstog[...]

15 Engine/Cylinder Head, Valv es 944 Remachining cylinder-head maling face Checking cylinder head for distortio n Use a feeler gage an a straigh t edge or a precision straight edge to check the m aling face of the cylinder head for distortion. Permissible maling-face uneve ness: 0.05 mm Cylinder heads wi th distorted maling faces can be remachined [...]

944 Engine/Cylinder Head , Valves 15 NOTES ON ASSEMBLY REMOVING AND INSTALLING VALVE SPRINGS Cylinder head removed Remove and install valve spring s with US 1020 + US 1020/1. REMOVING AND INSTALLING VALVE SPRINGS Cylinder head installed Remove and install valve spring s with Special Tool 9242. REMOVING VALVE STEM SEAL Remove valve stem seal wi th S[...]

15 Engine/Cylinder Head , Valves 944 INSTALLING VALVE STEM SEAL Note: Always remember to place an 1 mm thick washer on the cy linder-head face before installing the valve stem seal. 1. Lubricate valve stem and instal l shaft. Place an 1 mm thick w asher on cylinder-head face. Push drift over valve stem. Lubricate sealing lip of valve ste m seal and[...]

944 Engine/Cy linder Head, Valve Drive 15 Checking the valve guides 1. Clean the valve guides thorou ghly. 2. Use a new valve to m easure the tilt play. 3. Mount bar gate holder V W 387 on the cylinder head. The dial gaugemust be aligned parallel to the valve disk. 15/2 15/3 4. The tilt play is m easured w ith 1 0 mm valve stroke (distance betweent[...]

15 944 15 - 124 Blank page[...]

944 Engine/Cy linder 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 valv e guides Printed in Ge r many - XVII, 1988 15 - 125[...]

15 Engine/Cylinder Head, Valv e Drive 944 Drawing Plunger to press out the valve guide 15 - 126 Replacing valv e guides Printed in Ge r many - XVII, 1988[...]

944 Engine/Cy linder Head, Valve Drive 15 Drawing Plunger to press out the valve guide Plunger to press in the valve guide Replacing valv e guides Printed in Ge r many - XVII, 1988 15 - 127[...]

15 Engine, Cylinder Head, Valve Drive 944 Replacing the valve guides 1. Clean and inspect the cylinde r head. It is inexpedient to replace the v alve guides in cylinder heads whe re rem achining 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 s[...]

944 Engine, Cy li nder Head, Valve Drive 15 7. Ream the valve guides wi th Special Tool 3120 Proceed as follow s: The valve guides must always be rea med wi th "petroleum" lubricant W ithd raw the reamer regularly to remove chips. Then finish-rea m the boreagain with a dry rea m er. 87/920 8. The valve seat rings m ust be re m achined alt[...]

15 Engine, Cylinder Head, Valve Drive 944 Checking the valve seat wear limit 1. The valve seats in the 4-v alve cylinder heads can be remachined. At the same time, the wear limit dimensio n m ust not be exceeded as this would m ean that the hydraulic valve tappe ts m ay no long er function correctly. Wear dimension Intake valve Exhaust valve As fro[...]

944 Engine, Cy li nder Head, Valve Drive 15 Checking and remachining valve se ats Visuel inspection 1. Check that the valve seat sits securely in the cylinder head. 2. Check the contact pattern. If the valv e does make contact over the emire surface of the valve seat. remiII the seat slighdy. Remachining 1. Valve seats can be remachined, for exampl[...]

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 va lve seats lightly with grinding paste. Check the contact pattern af the valve sea t surface. Valve dimensions 15/127 Valve dimensions 944 S As from Model 87 Engine type M 44.40 Dimension Intake Exhaust a [...]

944 Engine, Cy li nder Head and Valve Dr ive 15 Checking and adjusting installa tion length of valve springs Valve springs, Model 87 onward Engine type M 44.40 Note W hen sel ecting the valve-spri ng seat (own construetion) alw ays ensure that the valve- spring seat is 2.0 + 0.2 mm thick. 1/03 Tool (own construetion) Valve spring Sp No . 944.105.46[...]

15 Engine, Cylinder Head and Valv e Dri ve 94 4 5. Using a depth gauge, measure from the top surface of the valve-spring seat, vertically downwards through the rece ss to the outer spring contact sur face. 86/930 Installation length Inlet valve Exhaust valve 38.0 + 0.5 mm 37.0 + 0.5 mm 6. The installation leng th can be adjusted using shims. 7. The[...]

944 Engine/Lubrication 17 CHANGING ENGINE OIL AND ENGINE OIL FIL TER (16-VALVE ENGINES) Preconditioned: Engine at operating temperature. 1. Unscrew and rem ove oil filler cap. 2. Unscrew oil drain plug from oil pan and drain engine oil. 3. Remove oil filter with oil-filter wren ch, Special Tool 9204. Catch remaining oi l. 4. Clean drain plug and ne[...]

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 an d undo the set screw by 2 rum s. 2. Ease the pressure reducing valve out of the seat with a screwd riverand take out upwards. 3. Replace the O-ri[...]

944 Engine/Cooling 19 MIXING TABLE FOR COOLANT (Average values) Antifreeze effective to Antifreeze Agent W ater 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 SYSTE M FOR LEAKS (16-VALVE ENGINES) 1. Visual inspection for leaks. 2. Check routing of cooling an[...]

20 944 20 - 100 Blank Page[...]

944 Fuel Supply 20 REPLACING FUEL FILTER (16-VALVE ENGINES) 1. Disconnect fuel lines, alway s counter when slackening threaded conn ectors. Catch fuel exiting from lines in a suitab le container. 2. Slacken retaining cla m p and re m ove fuel filter. 3. Install new filter. Direction of f low is as indicated by the arrow . CHECKING FUEL AND INJECTIO[...]

20 Fuel Supply 944 CHECKING DELIVERY RATE OF FUEL PUMP Precondition: Fuel filter and powe r supply OK. 1. Unbolt fuel return hose fro m pressure regulator. Connect a length of commercially available fuel hose and place one end in a graduated cylin der (capacity apprax. 1500 cc). 2. Disconnect DME relay fro m central electrics and, using a length of[...]

944 Fuel Supply 20 FUEL SYSTEM LINE ROUTING (16-VALVE E NGI NES) '87 MODELS ON W ARD 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 v alve a from fuel tank b to fuel tan[...]

24 944 24 - 100 Blank Page[...]

944 L-Jetronic Fuel Injection 24 REPLACING AIR FILTER ELEM ENT (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 lowe r half of air-filter housing with a lint-free cloth 4. Insert filter ele m ent, place housing cover in posi tion and tighten mounting [...]

24 Air Flow Controlled Fuelinjection 944 Testing and adjusting specifications Model 87 onward Engine type M 44.40 /41 (3.0 I) Test Specifikation Rem arks Electric fuel pump Min. delivery rate 850 cm 3 /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[...]

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 nu t 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 V W 1318 to test connection. 3. Disconnect DME relay fro m central e[...]

944 A ir Flow Controlled F uel Injection 24 Checking idle speed and CO- with catalytic conv erter Model 87 onward Engine type M 44.40 /41 (3.0 l) Note It is no longer possible to adjust idle spe ed or CO on vehicles with catalytic con verters. The Lambda probe remains conn ected while chekking idle speed and CO. Checking precondition s Engine in pe[...]

24 Air Flow Controlled Fuel Injec tion 944 Checking idle speed and CO without catal y tic 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 conn ector adjustment therefore no long er applies. Idle/CO adjustment Adjustment preconditions Engine in perfect mechani cal c[...]

944 A ir Flow Controlled F uel Injection 24 Replacing air filter inser t Model 89 onward Engine type M 44.41 (3.0 l) 1. Replace front end plate. Refer to 944 W orkshop Manual Page 50 - 5. 2. Undo retaining clips and re m ove ho using cover with filter insert. 3. Clean inside of filter housing with lint-free cloth. 4. Install new filter insert. Obse[...]

26 944 26 - 100 Blank Page[...]

944 Exhaust Syste m 26 CHECKING TIGHTNESS OF EXHAUST SY ST EM FLANGES (16-VALVE ENGINES) 1. Check tightness of exhaust flanges and check entire exhaust system for leaks. 2. Check tigh tness of hex nuts on exhaust manifold/cylinder hea d flange. 3. Check tigh tness of all flange connectians in exhau st system, together with oxygen sensor and exhaust[...]

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 W ithout 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 W R 7 DC Spark gap 0.7 + 0.[...]

28 Ignition System 94 4 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 Re m arks 944 S 944.606.145.00 Tightening torque = 20 Nm (14 [...]

944 Egnitio n 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- m ap sw itch 2 - Plug for variant sw itch Country Characteristic-map swi tch, ter. 54 Varient switch, ter. 39 USA, rest of world with catalytic converters California,[...]

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 N m (18 - 22 ftlb). 28 - 104 Repl acing Spark Plugs Printed in Germany[...]

944 Ignition Sy ste m 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 Versio n Remarks 944 S 2 928 602 211 01 Bosch No. 1 235 522 395 Only high-tension distribution Spark plugs Type/Model Vers[...]

28 Ignition System 94 4 DME Control unit Type/Model Version Re m arks 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 (wit[...]

944 Ignition Sy ste m, Diagnosis 28 Coding - DEE control unit 94 4 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 sw itch Country Va riant switch USA, rest of world with catalytic convertor California, Japan 928.607.421.00 Rest of world wi thout catalytic converter 928.607.422.00[...]

DME-Diagnosis / Troubleshooting Dr. Ing. h.c. F. Porsche A k tiengesellschaft[...]

944 S/944 S2 Fuel Sy ste m - 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 Require m ents Effects of Faults (Cross Reference List) DME Control Unit Plug Conne ctions Power Supply Idle Speed Contact Full Load Contact Engine Temp[...]

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 introdu ction of electronic ignition systems in standard pro duction some time ago already. Nor mally the ignition power of electronic systems (almost all makes) will be g[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Important Vehicle Inform ation Always turn off the ignition or di sconnect the battery for resistance tests (if not, the tester could be destroyed). Always disconnect the speed sender plug for compression tests (if not, there cou ld be dangerous high tension and damaged insulation on the ignitio[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Equipnient Required for DME Te sts: - Diagnostics tester 9288 (9268) with connecting leads - 1 oscilloscope approved by Porsche - 1 digital display multimeter w ith an internal resistance of at least 10 M-o hms - 1 Bosch L-Jetronic test lead, Bosch No . 1684 463 093 (che ck read f or correct polar[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Diagnosable DME Control Unit Self- diagnosi s with a fault m emory, w it h which it is possible to detect and store certain injection. ignition and knock regulating sy st em f aults, is in tegrated in the DME control unit of 944 S cars beginning with 1988 model s. The DME control unit has a per [...]

24/28 Fuel System - Electronic Control 944 S/944 S2 This DME 944 S Diagnosing/Troub leshooting 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 lo[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 This page ar e missing or blank in the book ! DME - Diag nosing/Tro ubleshooting Printed In Ge r many - XXI, 1989 D 24/28 - 7[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 This page ar e missing or blank in the book ! D 24/28 - 8 DME - Diag nosing/Tro ubleshooting Printed In Ge r many - XXI, 1989[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks 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. [...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 2: Idle speed contact ( ) Ground short Fault Code 1_12 Check via circuit input test w ith 9288 System Tester or 9268 Tester. Select test step and operate accel erator pedal. 9288 Display: Idle speed contact made Idle speed contact[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 3 Full load contact ( ) Ground short Fault Code 1_13 Check via circuit input test w ith a 9288 System Tester or 9268 Tester. Select test step and operate accel erator pedal. 9288 Display: 9268 Display: Full load contact broken F[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 4 Engine tamp. sensor (NTC II/ ) Fault Code 1_14 Engine temperature can be read di rect from the "actual value" menu with a 9288 System Tester. No Plausible Display: Connect ohmmeter on terminal 45 and terminal 24 of the[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 5a: Air flow sensor (V/ ) Fault Code 1_21 The ratio between Up (potentiom eter voltag e) and Uv (power supply voltag e) can be read in the "actual value " m enu w ith a 9288 System Tester. W hen o pening the ai r flo w[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks Turn off ignition and reconne ct plug if the voltage values have been reached . Remarks: Control unit produces replace m ent valu es in case of air flow sensor failure (emergency running program ). Injection signal from nominal air of the id[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks Connect two-pin DME test lead (Bosch No. 1 684 463 093) between the spee d control and plug. Connect and adjust engine tester to supplied operating instructions. Make sure that ele ctric lead connections do not have contact with vehicle gr[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks 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 wi th a 9288 System Tester. If not: Disconnect oxygen sensor plug . Connect a digital d[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks If no display: Disconne ct plug on air flow sensor. Connect an ohmmeter on air flow sensor terminals 1 and 4 with he lp of t est l eads. Display: same as abov e. Note: In case of a break, there wil l be a replacem ent valu e equal to an in[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 12: Control unit (knock computer) Fault Code 1_33 Ignition timing is retarded 6° in case of t his fault. Replace control uni t. Test Point 13: Hall signal Fault Code 1_34 Disconnect plug on cylinde r head behind the camshaft driv[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Fault, Fault Code Possible Causes, Elimination, Re marks Test Point 15: DME relay (fuel pump) (V) Start the engine - fuel pu m p must run during engine starting . It not: Turn off ignition. Disconnect control un it plug. Connect terminal 3 and terminal 24 on the control unit plug w ith h elp of [...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Fault, Fault Code Possible Causes, Elimination, Re marks Tank venting valve is not activa ted permanently. Test must be performed w ithin 7 minutes after starting an engine having operating temperature (interrupt tank v enting valve activation approx. 75 seconds afterward and then con tinue). Star[...]

944 S/944 S2 Fuel Sy ste m - 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 cou ld fall out! Connect P 378 pressu re tester on the test connection. Start the engine. Vacuum on pressure regulator at idle speed : Tes[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Test Point 19: Intake System leaks Check all connection s after t he air flow sensor for leaks. Remov e upper air cleaner section. Apply Special Tool 92 64/4 on the air flow sensor and produce approx . 0.5 bar pressure in the intake system. Leaks w ill cause the pressure in the system t o drop qui[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Plug Connections Are all plugs connected correctly, not loose and not corroded? Disconnect plugs and check whe ther pins and terminals of plugs are bent or corrode d. 55-pin plug an DME control uni t (behind floor plate in the front passen ger's footwell). 14-pin plug in engine compartment [...]

24/28 Fuel System - Electronic Control 944 S/944 S2 Test Point 21: Speed/Reference Mark Sender This test can only be performed w ith an osc illo- scope. Connect and adjust a wo rkshop oscillo- scope according to the suppl ied operating instructions for this purpose . Connect the positive tester lead via a test lead on control unit plug terminal 47 [...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 No display: Disconnect plug of speed sende r on plug plate in the engine compart m ent. Conn ect tester leads on middle and outside pins of the plug on the sender en d of the plug with help of test leads (terminal s 1 and 2, pin end). Start the engine. Sinuso idal oscillation must be displayed o[...]

24/28 Fuel System - Electronic Control 944 S/944 S2 d) Ignition timing test Ignition timing is checked w ith t he engine at operating temperature. Ignition timing and engine speed can be read direct in the "actual va lue" m enu wi th a 9288 System Tester. Test value: (944 S + 944 S2) At 840 +- 40 rpm 10° +- 3° e) Activation of high tens[...]

944 S/944 S2 Fuel Sy ste m - 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 nega tive tester lead on terminal 2 of the disconnected final stage plug. Operate starter motor. Oscilloscope should display the control signal of the DM[...]

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. Conne ct voltmeter on injector plug terminal 2 and gro und with help of test leads. Turn on ignition. Display: battery voltage If there is no disp[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Test Point 24: A lte rnator, Regulator Misfiring of the engine coul d be caused by the peak voltage of the al ternator. Take drive belt off of the alterna tor. Start the engine. Check alternator and regulator if the disturbances have been eli m inated. Test Point 25: Leads K and L Connections fo[...]

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 syste m after adjusting the CO lev e l. An adapter plug (911.612.42 2.8) must be con- nected on the oxygen sensor con necting lead of cars without a catalytic conv erter, in order to avoid dif[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Coding of Control Unit - 944 S Pertinent curve families are integra ted 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 Syste m Tester. One each 2-pin and 3-pin plu g, whi[...]

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 '9 1, the code f or Cal ifornia and Japa[...]

944 S/944 S2 Fuel Sy ste m - Electronic Control 24/28 Check-Engine Lamp (Malfunction Indicator Light M.I.L) As from model year '9 1, Califom ian legisl ation prescribes a waming lamp which lights up if a part relevant to the exhaust gas fails. As a function check of the warn ing lamp, it lights up when the ignition is switched on and goes out [...]