Porsche 1989 944 S2 Workshop Manual Download Page 135

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944 S/944 S2

Fuel System - Electronic Control

24/28

Test Point Description

Page

Precautions

Important Vehicle Information

Testing Requirements

Effects of Faults (Cross Reference List)

DME Control Unit Plug Connections

Power Supply

Idle Speed Contact

Full Load Contact

Engine Temperature Sensor

Air Flow Sensor

Idle Speed Control Activation

Oxygen Regulation Stop

Oxygen Sensor

Intake Air Temperature Sensor

Knock Sensor I

Knock Sensor II

Control Unit Faulty

Hall Signal

Control Unit Faulty

DME Relays

Tank Venting Valve

Check Engine Waming Lamp

Fuel Pressure

Intake System Leaks

Ground and Plug Connections

Speed/Reference Mark Sender

Ignition and Final Stage

Fuel Injectors - Injection Control Unit

Alternator / Regulator

Leads K and L

CO and Idle Speed Test

Coding of Control Unit

Check-Engine-Lamp

DME - Diagnosing/Troubleshooting

Printed In Germany - XXI, 1989

D 24/28 - 1

Summary of Contents for 1989 944 S2

Page 1: ...Workshop Manuel Volume IA Engine 16 valves DR ING h c F PORSCHE Aktiengesellschaft As webpage by http www 9ss1 dk porsche944...

Page 2: ...nd cylinder bore Pistons from Model 89 onward Installing cover for oil centrifuge partition Engine Cylinder head Valve drive Camshaft salling checking and adjusting Camshaft salling checking and adjus...

Page 3: ...44 40 Fuel preparation L Jetronic regulation Replacing air filter cartridge checking intake air guide hoses Testing and adjusting specifications Checking fuel pressure Checking idle speed and CO with...

Page 4: ...944 General TYPE 944 S 16 VALVE ENGINES 87 MODELS ONWARD Printed in Germany XIII 1987 Technical Data 0 9...

Page 5: ...orque SAE J 1349 Max spec power output Net power SAE J 1349 Fuel octane rating Max perm engine speed Engine weight dry ENGINE DESIGN Type mm in mm in cc in 3 kW PS kW HP rpm Nm kpm rpm Nm lbft kW l HP...

Page 6: ...arings Plain Cast opt sinter forged Plain Light alloy cast Forged Plain bearings with bearing shells Light alloy Light alloy Press fit special brass 2 intake 2 exhaust overhead V Two overhead camshaft...

Page 7: ...changer in main oil flow and secondary water flow integrated in crankcase Approx 4 bar at operating temperature Pilot lamp and pressure gage 140 C Up to 1 5 Standard 2 double wall manifolds branch pip...

Page 8: ...gnition Firing sequence Ignition timing RON MON l 100 km l 100 km l 100 km V Ah A W DME Digital Motor Electronics 1 electric fuel pump Standard 95 85 European standard premium unleaded possible Opt M2...

Page 9: ...Height Wheel base in design pos Track Front Rear Ground clearance at per total weight Bed clearance at per total weight Overhang angles Front Rear mm in mm in mm in mm in mm in mm in mm in mm in mm in...

Page 10: ...bs kg lbs kg lbs kg lbs kg lbs kg lbs kg lbs Standard 640 1411 650 1433 640 1411 650 1433 1280 2822 730 1609 900 1984 1600 3527 1200 2646 1200 500 1102 500 2760 6085 2760 50 110 50 35 77 75 165 Sports...

Page 11: ...pprox 6 0 l Approx 8 5 l Approx 2 0 l hypoid oil SAE 80 to MIL L 2105 APl classification GL 4 Approx 80 l including approx 8 l reserve Approx 0 2 l Approx 0 6 l PERFORMANCE Maximum speed Acceleration...

Page 12: ...I 104 4 09 88 3 46 2990 182 5 Displacement rounded down cm3 2969 Compression ratio Max engine power 88 195 EEC Net power SAE J 1349 at engine speed Max torque 88 195 EEC Net torque SAE J 1349 at engin...

Page 13: ...rs The con trol unit capable of diagnosis is identified by an altered part number A specially developed diagnostic tester special tool No 9268 is then used to read out the error memory and to test spe...

Page 14: ...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 control unit error diagnosis Printed in Germany XVI 1987...

Page 15: ...After connecting the tester the following dis play must appear Display If this is not the case check the tester ter minals or check the power supply of the diag nosis socket in the car by referring to...

Page 16: ...Pin 8 Pin 9 Pin 10 Pin 11 Pin 12 plug unused unused unused unused unused Round plug Pin 4 Pin 1 Pin 7 Pin 6 Pin 2 Pin 5 Pin 3 34 Switch on the ignition Display The ignition must not be switched off du...

Page 17: ...ce for the DME control unit then takes place If an error is displayed take the note of the error e g 1211 Display The error is displayed until the green key is again pressed on the tester The next err...

Page 18: ...ion 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...

Page 19: ...or tangibly operate and can thus be detected as being electrically in proper working order or defective An error display via the tester is not possible in this mode but faulty input signals or their w...

Page 20: ...tempts are made to start the engine starting difficulties may occur because a slight residual amount of fuet is injected during this testing step The testing steps remain in operation until the green...

Page 21: ...tact see Idle contact troubleshooting If the display 0000 does not appear it is pos sible to switch at all times to the next testing step Press the green key until the clear symbol appears Initiate th...

Page 22: ...f an error check with reference to the circuit diagram Do not switch off the air conditioning system Initiate the air conditioning control terminal 40 testing step Display Switch off the air condition...

Page 23: ...nce Self diagnosis 03 Press the green key until the clear symbol appears Display End of the actuator and input signal function checks Actuator and input signal function checking Printed in Germany XVI...

Page 24: ...03 944 03 12 Blank page...

Page 25: ...Components 1311 1321 1322 1332 1333 1334 1335 Injection valves Rotary idle controller Solenoid valve tank bleeding Idle contact Full load contact Air conditioning AC switch Air conditioning compressor...

Page 26: ...03 944 03 14 Blank page...

Page 27: ...he engine to be at operating temperature Ignition off Press the yellow key the number af times required for the function symbol to appear on the function display Display Press the green key until the...

Page 28: ...03 944 03 16 Blank Page...

Page 29: ...rating temperature during the test Testing most be carried out during a test drive or on the roller test stand Knock detection Engine at operating temperature While the engine is running simultaneousl...

Page 30: ...s over from the clear symbol to the knock detection symbol This is always the case once 10000 ignitions have occurred All occurring knocks are added up and displayed as the end result To restart knack...

Page 31: ...oting the entire error memory must be read out Error code 1111 The supply voltage is too low 10 V or too high 16 V Possible causes for too low a supply voltage Battery exhausted Poor contact on the gr...

Page 32: ...he DME control unit 32 Connect a ohmmeter between terminal 52 and terminal 24 on the DME plug Display Throttle valve closed R 10 Throttle valve open R Switchover must already occur if the throttle val...

Page 33: ...ion R 10 The switching point must be briefly before full load If the values are not reached in this testing step measurement must be repeated directly on the throttle valve switch Error code 1114 This...

Page 34: ...perature sensor NTC 2 in forms the control unit about the current engine temperature It results in mixture enrichment during cold starts or hot running Error code 1121 This error code draws attention...

Page 35: ...air flow sensor plug ter minal 3 and plug terminal 4 to air flow sensor plug terminal 4 using an auxiliary cable Measure the voltage between terminal 2 of the air flow sensor and ground Display appro...

Page 36: ...ch a mixture No partial vaccum on the pressure regulator Injection valve does not close Return to the fuet tank clogged Error code 1124 This error code draws attention to an error in the area of the L...

Page 37: ...ure sensor NTC 1 in the air flow sensor Possible errors Ground fault Short to positive Wire discontinuity NTC 1 defective Testing the intake air temperature sensor Connect an ohmmeter between terminal...

Page 38: ...an error in the area of knock sensor 2 87 910 Error testing of the knock sensors is an active error test i e error testing is carried out during driving If an error has occurred first check the wirin...

Page 39: ...code draws attention to an error in the area of the Hall generator 87 904 Possible errors Ground fault Short to positive Wire discontinuity Testing the Hall generator signal Using a suitable auxiliary...

Page 40: ...1 V must be measurable between pin 1 positive and pin 3 negative If this is not the case check the wiring with reference to the circuit diagram Error code 1141 Error code 1141 draws attention to an er...

Page 41: ...flow sensor Lambda control detects a too rich too lean mixture Lambda probe signal not correct NTC 1 Knock sensor 1 Knock sensor 2 Knock control in the control unit Hall generator signal DME control u...

Page 42: ...03 944 03 30 Blank page...

Page 43: ...r symbol appears on the function display Display The error memory is reset if the LED goes off and the function display changes to 0000 Display Note A test drive must be carried out after resetting th...

Page 44: ...diagnosis Systems Ignition on Engine standing still Engine running 944 S 944 S2 DME Airbag Alarm system yes yes yes to n 2000 rpm yes yes Webdesign from www 9ss1 dk porsche944 03 32 Operating conditi...

Page 45: ...944 Self diagnosis 03 Operating instructions for System Tester 9288 Operating instructions for System Tester 9288 Printed in Germany XXIV 1991 03 33...

Page 46: ...rview Setting up printer Switching off unit Key N Return to the next higher program level following termination of a test sequence or during a test sequence return to the last display Key Storing indi...

Page 47: ...gnosis circuit inputs and system adaptation engine knock detec tion sensor and event check for the tire pressure monitor RDK 3 1 Reading out the error memory Connect the Systemtester 9288 see 2 Switch...

Page 48: ...t accord ing to repair instructions Continue Proceed with key Fault repaired 1 yes 3 no Return to display No of errors with key 3 Proceed with key 1 Fault memory 1 Erase 3 Do not erase If key 3 is pre...

Page 49: ...g the key N the operator is returned to the menu 3 3 Circuit inputs In addition lo the actuators the Systemtester 9288 can also check circuit inputs To this end operate the Systemtester 9288 in accord...

Page 50: ...he EZK or DME control unit To this end operate the Systemtester 9288 as described in 3 1 until the following display appears Installed systems 1 LH 2 EZK 3 RDK The particular system can be selected by...

Page 51: ...d for instance with key 1 Printer setting 1 IBM 2 HP Quiet Jet 3 EPSON The selection of the printer results in the tester being set up for the printer type in question 3 7 Store measurement displays K...

Page 52: ...10 944 10 0100 Blank page...

Page 53: ...tensioner Banjo bolt Chain tensioner Cover for cylinder head Fastening Hall sensor M 12 x 1 5 M 10 M 8 M 6 M 8 M 12 M 12 M 8 M 6 M 8 x 1 M 6 M 6 30 22 60 torque angle 20 15 50 37 1 st stage 2nd stage...

Page 54: ...marks Valve timing Camshaft bore Camshaft Camshaft Bucket tappet bore Bucket tappets Camshaft Opening temperature opens at excess pressure opens at vacuum l 600 miles excess pressure 6 l from MY 88 I...

Page 55: ...n rings M 44 41 Distortion Intake Inner dia Dia Dia Rocking clearance Clearance Height clearance Height clearance Groove 1 Groove 2 Groove 3 Groove 1 Groove 2 Groove 3 Ring gap clearance Ring gap clea...

Page 56: ...Bore for balance shaft bearing sheIIs at crankcase or balance shaft cover Bore for bushing in bearing housing Balance shaft Dia Dia Radial clearance Runout Dia Radial clearance Axial clearance Dia Rad...

Page 57: ...arks Engine suspension beam 3033 VW Special Tool In conjunction with workshop crane e g Bilstein K750 H Note If necessary use a commercially available carabiner load bearing capacity 650 kg to connect...

Page 58: ...d Disconnect battery positive lead Disconnect wire harness and push both cables with rubber grommets through splash wall Open cable clips 5 Unbolt panel in passenger side footwell and remove Unbolt ca...

Page 59: ...on position of rotor Remove oil filter and ATF reservoir 10 Remove throttle valve actuating cable complete with reversing roller and holder Disconnect oxygen sensor plug connector Slacken hose clamps...

Page 60: ...acket from radiator and remove by lowering from car 16 Slacken coolant hose and breather hose from top left of radiator and remove Disconnect electrical connection from temperature switch to radiator...

Page 61: ...oler and steering and disconnect line 22 Disconnect servo pump from bracket moving spacer sleeve forward to remove Leave servo pump hanging from steering 23 Disconnect left and right control arms from...

Page 62: ...axle bell housing mounting bolts 30 Disconnect coolant hoses for heating above exhaust manifold and from cylinder head 31 Attach VW Special Tool 3033 suspension beam to transport bracket of engine as...

Page 63: ...axle cross member Tightening torque of mounting bolts 42 Nm 31 ftlb 3 Install control arms pressing sleeve in rubber metal bearing down slightly to facilitate installation 4 Place a 4mm thick steel w...

Page 64: ...oolant 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 Remo...

Page 65: ...orldwide Compression 10 9 1 Nominal dia 100 00 mm An arrow pointing toward the belt pulley indicates the installation position 1 2 3 Plain compression ring chrome plated Oil scraper ring Three part oi...

Page 66: ...easure approx 61 mm from piston crown 90 offset from piston pin axis Checking cylinder bores Measure approx 61 mm from upper edge of cylinder bore transverse to engine block Mount lower crankcase sect...

Page 67: ...480 104 490 0 007 104 500 1 04 500 104 510 0 005 104 520 I 0 I 1 I 2 Checking pistons Measure approx 52 mm from crown of pis ton 90 offset to axis of piston bolt Checking cylinder bore Measure approx...

Page 68: ...13 944 This page are missing or blank in the book 13 104 Blank...

Page 69: ...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 circum...

Page 70: ...15 944 15 100 Blank page...

Page 71: ...944 Engine Cylinder 15 This page are missing or blank in the book Printed in Germany Unknow page 15 101...

Page 72: ...15 Engine Cylinder 944 This page are missing or blank in the book 15 102 Unknow page Printed in Germany...

Page 73: ...rotor and lock camshaft sprocket with 3 M 5 x 15 to prevent camshaft sprocket or camshaft turning when camshaft central bolt is slackened 4 Slacken camshaft central bolt note that it is essential to...

Page 74: ...bolt and temporary retaining bolts while doing so ensure that the reading of 1 4 0 1 mm an the dial gage is not changed 10 Now turn crankshaft slowly until dial gage shows that piston has reached the...

Page 75: ...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 accordi...

Page 76: ...on the new camshaft sprocket over the old sprocket and transfer the TDC mark to the new sprocket using a color pencil 2 Fit new camshaft sprocket and adjust camshaft timing as described in the Repair...

Page 77: ...pecial Tool Remarks 1 2 3 4 Assembly bridges for installing camshafts Pressure piece for sealing ring Assembly drift for sealing ring Angle reader 9248 9234 9233 In conjunction with clamping bolt from...

Page 78: ...lter Detach entire filter assembly and remove 5 Remove air flow sensor and disconnect support M 8 bolt from intake manifold 6 Remove throttle valve actuating able complete with reversing roller and ho...

Page 79: ...d remove 10 Remove engine underguard Open coolant drain plug and catch coolant in suitable container 11 Detach exhaust at exhaust manifold flange 12 Pull off spark plug caps and remove distributor cap...

Page 80: ...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 1...

Page 81: ...ts with chain and lay together on one side 22 Undo cylinder head Undo in sequence from outside to inside 23 Remove cylinder head Note If oil has been mixed with water the cylinder head must be subject...

Page 82: ...st stage 2nd stage 3rd stage 20 Nm 90 torque angle 90 torque angle Model 89 onward Engine type M 44 41 3 0 I Note The cylinder head has been reinforced by 20 mm in the area of the bearing surfaces for...

Page 83: ...ing on the intake camshaft and the markingon the exhaust camshaft amounts to 7 outer chain links the distance betweenthe cast lugs measures approx 113 mm 11838 4 Fasten the camshafts to the cylinder h...

Page 84: ...ece 9234 to drive the sealing ring into position at the drive end of the camshaft Lubricate the sealing lip before assembly 11794 Note The timing chain must always be replaced if the valves have beend...

Page 85: ...te 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 bearin...

Page 86: ...face Timing 1 mm stroke zero play Inlet opens Inlet closes Exhaust opens Exhaust closes 944 S M 44 40 944 105 277 04 944 105 275 04 277 04 275 04 4 CS 40 CS 36 CS 4 CS atter TDC atter BDC before BDC b...

Page 87: ...suitable retainer improvised tool Installing 1 Chain tensioner can be installed without removal of retaining clamp 2 The retaining clamp for the chain tensioner plunger must be removed once the chain...

Page 88: ...15 944 This page are missing or blank in the book 15 114 Blank page...

Page 89: ...HEAD 16 VALVE ENGINES No Description Special Tool Remarks 1 2 3 Puller for valve stem seals Press in tool for valve stem seals Valve spring assembly tool 9237 9225 1 9242 Or US 1020 US 1020 1 Printed...

Page 90: ...15 Engine Cylinder Head Valves 944 DISASSEMBLING AND ASSEMBLING CYLINDER HEAD 16 VALVE ENGINES 15 116 Disassembling and Assembling Cylinder Head Printed in Germany...

Page 91: ...upport Washer Valve stem seal Intake valve Exhaust valve Valve guide 16 32 16 16 16 X 16 8 8 16 Withdraw with a magnet do not mix up Note number Oil Check correct seating Redetermine if necessary Alwa...

Page 92: ...bridge Lever arm Magnetic removal head Assembly head Spacer Screws Supplier Sauer Hamburg Supplier Sauer Hamburg Supplier Sauer Hamburg Supplier Sauer Hamburg Supplier Sauer Hamburg Commercially avai...

Page 93: ...be pulled out with the magnetic removal head 4 Fasten the assembly head to the lever arm Prags the tensioningarms toget her and place the conical valve keepers in the asssembly head 87 926 5 Place was...

Page 94: ...hieve a smooth surface Max machining depth 146 6 mm Note on machining maling face Peak to valley 0 015 mm If the new dimension tolerance is exceeded during machining a cylinder head gasket with a thic...

Page 95: ...tall valve springs with US 1020 US 1020 1 REMOVING AND INSTALLING VALVE SPRINGS Cylinder head installed Remove and install valve springs with Special Tool 9242 REMOVING VALVE STEM SEAL Remove valve st...

Page 96: ...n 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 i...

Page 97: ...ilt play 3 Mount bar gate holder VW 387 on the cylinder head The dial gaugemust be aligned parallel to the valve disk 15 2 15 3 4 The tilt play is measured with 10 mm valve stroke distance betweenthe...

Page 98: ...15 944 15 124 Blank page...

Page 99: ...15 Replacing valve guides Tools 87 918 No Description Special tool Remarks 1 2 3 4 Ejection base Plunger Plunger Reamer 3120 See drawing See drawing See drawing VW special tool Replacing valve guides...

Page 100: ...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...

Page 101: ...944 Engine Cylinder Head Valve Drive 15 Drawing Plunger to press out the valve guide Plunger to press in the valve guide Replacing valve guides Printed in Germany XVII 1988 15 127...

Page 102: ...1 outer diameter 11 26 mm accordingly The pressing must amount to 0 06 0 8 mm for intake and exhaust valve guides Example Bore in the cylinder head measures 11 020 mm Machine the outside diameter of t...

Page 103: ...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 v...

Page 104: ...he hydraulic valve tappets may no longer function correctly Wear dimension Intake valve Exhaust valve As from Model 87 44 4 mm 43 4 mm 2 This is measured with the valve to be installed from the end of...

Page 105: ...1 Valve seats can be remachined for example with the Neway valve milleror the Hunger valve seat tuming tool 2 Remachine the valve seats with a 45 seat milling cutter Then machine the seat to the pres...

Page 106: ...valve seats lightly with grinding paste Check the contact pattern af the valve seat surface Valve dimensions 15 127 Valve dimensions 944 S As from Model 87 Engine type M 44 40 Dimension Intake Exhaus...

Page 107: ...944 105 467 03 Auxiliary spring Sp No 928 107 171 01 1 Machine a recess of approx 10 mm width into valve spring seat Only install valve spring seat for measurement 2 Shorten the auxiliary spring to a...

Page 108: ...valves must not be mixed up again after measurement Valve spring Model 89 onward Engine type M 44 41 3 0 l Note A new type of valve spring has been installed in engine type M 44 41 3 0 l from Model 8...

Page 109: ...drain plug and never forget to replace seal Tightening torque 50 Nm 37 ftlb 5 Lightly oil gasket of oil filter screw in by hand until gasket makes contact and turn through one further turn to tighten...

Page 110: ...rew 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...

Page 111: ...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 poro...

Page 112: ...20 944 20 100 Blank Page...

Page 113: ...container 2 Slacken retaining clamp and remove fuel filter 3 Install new filter Direction of flow is as indicated by the arrow CHECKING FUEL AND INJECTION LINES FOR LEAKS AND LOOSE CONNECTIONS 1 Visu...

Page 114: ...lly available fuel hose and place one end in a graduated cylinder capacity apprax 1500 cc 2 Disconnect DME relay from central electrics and using a length of wire jumper terminals 30 and 87 b Allow fu...

Page 115: ...lector tube 4 Pressure damper 5 Pressure regulator A Air flow sensor B Throttle valve housing C Intake tube D Idle actuator E Intake jet pump F Electric tank breather valve a from fuel tank b to fuel...

Page 116: ...24 944 24 100 Blank Page...

Page 117: ...sing with a lint free cloth 4 Insert filter element place housing cover in position and tighten mounting screws Check that upper part of air filter is correctly seated CHECKING INTAKE AIR GUIDE AND CR...

Page 118: ...rpm CO values ppm without catalytic converter 840 40 0 5 1 5 300 with catalytic converte 840 40 0 4 1 2 300 Idle speed can only now be checked Idle adjust ment no longer applies Measured upstream at...

Page 119: ...ronic 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 Pressu...

Page 120: ...2 Connect pressure gage with hose from pressure tester P 378 or VW 1318 to test connection 3 Disconnect DME relay from central electrics and jumper terminals 30 and 87 b with a length of electric wire...

Page 121: ...nsure that the intake paths do not heat up thus falsifying the CO value Ambient temperature 15 35 C 1 Fit standard exhaust adapter to the test connector of the catalytic converter Engine type M 44 40...

Page 122: ...up to operating temperature 70 90 C oii temperature Use oil tempe rature tester Special Tools 9122 and 9122 2 2 Check CO value If the CO value is not within the prescribed tolerances correct the sett...

Page 123: ...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 pos...

Page 124: ...26 944 26 100 Blank Page...

Page 125: ...er 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 s...

Page 126: ...28 944 28 100 Blank Page...

Page 127: ...ors 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 m...

Page 128: ...01 M 44 40 Spare part 944 S Mod 88 944 618 124 01 M 44 40 Hall probe for knock sensors Type Model Version Remarks 944 S 944 606 170 01 Knock sensor Type Model Version Remarks 944 S 944 606 145 00 Tig...

Page 129: ...istic map switch 2 Plug for variant switch Country Characteristic map switch ter 54 Varient switch ter 39 USA rest of world with catalytic converters California Japan 928 607 421 00 EC without catalyt...

Page 130: ...UGS 944 S 1 Pull off spark plug caps 2 Unscrew spark plugs with commercially available wrench A spark plug wrench is supplied as part of the car s toolkit Tightening torque 25 30 Nm 18 22 ftlb 28 104...

Page 131: ...ries 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 Spar...

Page 132: ...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...

Page 133: ...7 421 00 2 928 607 422 00 1 not used 2 connector for variant switch Country Variant switch USA rest of world with catalytic convertor California Japan 928 607 421 00 Rest of world without catalytic co...

Page 134: ...DME Diagnosis Troubleshooting Dr Ing h c F Porsche Aktiengesellschaft...

Page 135: ...egulation Stop Oxygen Sensor Intake Air Temperature Sensor Knock Sensor I Knock Sensor II Control Unit Faulty Hall Signal Control Unit Faulty DME Relays Tank Venting Valve Check Engine Waming Lamp Fue...

Page 136: ...e conformance with safety regulations and legislation of a pertinent country when working on or testing ignition systems The ignition ignition or source of power must always be switched off when worki...

Page 137: ...h tension distributor terminal 4 during operation Avoid voltage flashover from ignition coil terminal 4 to ignition coil terminals 1 and 15 control unit could be destroyed To avoid destruction of the...

Page 138: ...lead e g VW VAG 1501 2 control unit plug test leads local manufacture fitted with 4 flat male plugs N 17 457 2 Test leads must always be used for testing All sender and ignition timing signals of Por...

Page 139: ...the DME control unit is provided for diagnosing in cars since 1988 models 9268 Flashing Code Testers can be connected on this plug A 19 pin plug replaces the 12 pin plug beginning with 1990 L models...

Page 140: ...does not always indicate a fault in the pertinent component but could also concern the corresponding control unit or connecting leads paths between the component and control unit Troubleshooting on a...

Page 141: ...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...

Page 142: ...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...

Page 143: ...pply for DME control unit V too high too low Fault Code 1_11 b Power supply via DME relay Connect a voltmeter on terminal 24 and terminal 37 of the control unit plug with help of test leads Turn on ig...

Page 144: ...ttle valve closed Throttle valve opened to gap of 10 1 If the value of the idle speed contact is not reached in this test the test should be repeated direct on the throttle valve switch as described b...

Page 145: ...leads Display Throttle valve closed Throttle valve opened about 2 3rd of full gap 10 If the value of the full load contact is not reached in this test the test should be repeated direct on the throttl...

Page 146: ...e sensor II sends information about the engine temperature to the control unit It is used to provide a rich fuer air mix ture after a cold start or during warm up Break DME control unit of the 944 S s...

Page 147: ...b Voltage drop on air flow sensor plate potentiometer V Take off air cleaner connecting hose Connect pin 3 of the disconnected air flow sensor plug with air flow sensor plug terminal 3 and pin 4 with...

Page 148: ...nt 6 Idle speed control V Fault Code 1_22 only S2 Element Activation Menu If pulse cannot be heard check Power supply Connect a voltmeter on terminal 2 and ground of the disconnected idle speed contro...

Page 149: ...lse cannot be heard in spite of correct power supply and received signal Test Point 7 Oxygen regulation on stop Fault Code 1_23 Oxygen regulation cannot work in its regulating range in case at disturb...

Page 150: ...r approx 150 mV 900 mV depending on composition of mixture Remarks If the control unit recognizes an oxygen sensor voltage signal of more than 1 V or less than 0 1 V the control unit will switch over...

Page 151: ...connections according to wiring diagram Reconnecting sensors eliminates contact resistance Whether coolant or other liquids are in area of the knock sensor Replace knock sensor Ignition timing retard...

Page 152: ...tive test leads on terminals 1 and 2 of the adapter lead Start the engine This signal should be displayed when the Hall system is okay Ignition timing will be retarded approximately 6 in all speed ran...

Page 153: ...3 not 944 S Electric valve for brake booster will be opened more or less long depending on the engine load when an engine having operating temperature is running The opened time is determined by a gro...

Page 154: ...s the air flow rate increases Check path according to the wiring diagram if there is no signal Replace control unit if necessary Test Point 17 Check Engine warning lamp Fault Code 1_45 California as o...

Page 155: ...stopped and fuel pump running without vacuum on the pressure regulator this requires removing the DME relay and bridging terminals 87b and 30 Test pressure 3 8 0 2 bar Stop fuel pump Read pressure on...

Page 156: ...nd very large leakage in the intake system for example intake pipe gasket Test Point 20 Ground Connections V Ground read 2 x from wire harness to engine block battery ground lead on clutch bell housin...

Page 157: ...eft 3 pin Hall sender plug behind the camshaft drive gear 2 pin plug for knock sensor I between in take pipes for cylinder no 1 and 2 2 pin plug for knock sensor II between in take pipes for cylinder...

Page 158: ...nal 47 and negative tester lead via a test lead on control unit plug terminal 48 Crank engine with the starter motor Sinusoidal oscillation of at least 3 volts speed pulse and an applied higher amplit...

Page 159: ...ignition display Adjust secondary ignition display an the oscilloscope Connect tester leads according to the supplied operating instructions Note If a fault is displayed for all cylinders it is in the...

Page 160: ...4 Disconnect DME control unit plug Turn on ignition If battery voltage is new supplied intermittently to terminal 1 of the control unit with help of a test lead e g control unit plug term 18 a high te...

Page 161: ...disconnected final stage plug Operate starter motor Oscilloscope should display the control signal of the DME control unit Very important Coat the baseplate with a heat conducting paste prior to inst...

Page 162: ...t resistor 6 Check current path according to the wiring diagram if battery voltage is not displayed b Coil resistanee test of fuel injectors Pull off injector plugs Check coil resistance on the contac...

Page 163: ...gnosable control unit does not always have to be the DME control unit Checking Pull off plugs on diagnosable control units one after the other until there is 8 V Replace fault eausing control unit Tes...

Page 164: ...O level in these cars so that it is only necessary to check the actual state in such cars Requirements Engine at operating temperature Engine and ignition in perfect running condition All electric con...

Page 165: ...hich are bridged differently depending on the country version lead out of the DME wire harness to call these curve families Country Curve Family Switch 2 Pins Version Switch 3 Pins USA Federal States...

Page 166: ...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...

Page 167: ...code fully depress the accelerator pedal with the engine off and the ignition on for 3 seconds until the Malfunction Indicator Lamp flashes Then remove foot from accelerator If no fault is recorded i...

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Summary of Contents for 1989 944 S2

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