My 85 944 no tach bounce diary
#1
My 85 944 no tach bounce diary
Current issues:
- No fuel during engine cranking (needs reverified after fuel pump replacement)
- No tach bounce
- Speed/reference sensors
- Fuel pump
- Clutch slave cylinder (failed hopefully under warranty from Pelican)
- Various clamps, hardware, gaskets
- Resistance - Speed sensor 1010 ohms from the DME connector (pins 25,26)
- Resistance - Reference sensor 1018 ohms from the DME connector (pins 8,27)
- DME relay - tested with a friends Power Probe - all connections tested OK - audible click just before engine cranks when turning key
- AC voltage - Engine cranking - Speed sensor +/- 4.5V
- AC voltage - Engine cranking - Reference sensor .01V
- Fuel pump - 12VDC from battery to pin 4 on 9 pin connector behind vacuum booster - fuel pump ran
- Starter solenoid - 10.5V
- DME Relay connection
- bridged T30 to T87b - fuel pump ran
- 12VDC at T30
- 10.5VDC at T86
- DME connector
- 12VDC at T18
- 12VDC at T35
- Ignition coils
- Primary - .65 ohms
- Secondary - 6900 ohms
- DME relay is good based on
- Audible click from relay during starting
- Results from test with Power Probe
- DME is still questionable
- Car came with 2 DMEs
- PO said one was bad and purchased second as a replacement. Not sure which is in the car right now.
- Speed/Reference sensors are good
- New Bosch (BMW PN) units
- Resistance is in spec
- Wires from Speed/reference sensors are good
- Resistance is readable from DME connector to sensors
- AC current is readable from DME connector to sensors
- Swap DMEs
- Verify sensor gap using oscilloscope
- Verify continuity from DME pins 8,25,26,27 to VR sensor connectors using Power Probe
- If short found replace wiring
#2
Rennlist Member
1. Remove AFM from J boot and crank engine. Spray starter fluid into inlet of J boot. Does the engine start. If starts, it stalls if you increase throttle.
2.Remove the fuel rail with injectors from the intake manifold. Place each injector into a cup to get an idea on uniformity of fuel delivery rate. Crank engine and observe results and decide next action.
If 1 is yes the engine starts, then the ECU could be OK but not proof positive.
3. Put everything back together, remove the intake filter cartridge, crank engine and spray starter fluid into intake. If engine starts, warm up, and then blipp throttle to see outcome. Another piece of the puzzle.
4. Verify coolant temperature sensor using Clark Garage procedure. More information.
5. Look at all the data collected, to determine the next step.
2.Remove the fuel rail with injectors from the intake manifold. Place each injector into a cup to get an idea on uniformity of fuel delivery rate. Crank engine and observe results and decide next action.
If 1 is yes the engine starts, then the ECU could be OK but not proof positive.
3. Put everything back together, remove the intake filter cartridge, crank engine and spray starter fluid into intake. If engine starts, warm up, and then blipp throttle to see outcome. Another piece of the puzzle.
4. Verify coolant temperature sensor using Clark Garage procedure. More information.
5. Look at all the data collected, to determine the next step.
#3
Update on
Next steps
Next steps :
Next steps
- Swap DMEs
- Verify sensor gap using oscilloscope
- Verify continuity from DME pins 8,25,26,27 to VR sensor connectors using Power Probe
- If short found replace wiring
Next steps :
- Install clutch slave cylinder
- Connect clutch slave/master cylinders
- Power-bleed the clutch cylinders with Motive Power Bleeder
- Drain/fill trans fluid with RedLine MT90
- Double-check brake lines for leaks.
- Get 'er moving
#4
Update
Weird intermittent electrical issue. Sometimes electrical systems would work, sometimes not. Wiggling the negative battery cable would make electrical systems turn on
Weird intermittent electrical issue. Sometimes electrical systems would work, sometimes not. Wiggling the negative battery cable would make electrical systems turn on
- Replaced negative battery cable. Seems to have done the trick for now.
- Work around is pull headlamp motor relay. Have tested relay without 12v.
- Coil resistance is 88 ohms
- Continuity on pins 30/87a
- More tests to come
- Next step is replace relay with spare (condition unknown)
- Inspect for leaks
- Bleed system again
- Replace hard/soft lines between cylinders
#5
Rennlist Member
Same thing happened to my 944 when bleeding the Master/Slave cylinders. Just continue to pump clutch, and the air in line will bubble up to the reservoir. Make sure the fluid level is higher than the clutch hose fitting in the MC
#7
Thank you! I was fussing with it last night and did this (with the res cap off) and the pedal firmed up!