GuilhermeRocha

Well well well.. this car is going to ruin me..
So.. here are the symptoms:
When i turn on the key and the car is cold, everyhing is good. When things get hot, its a different story. The car cannot keep idle, always loosing rpm when hot. When driving hard I ear alot of intake "bangs".. car also seems to run on 5 cilinders.. vibrates and misfires alot when on the gas.

WHAT IT CANNOT BE / ALREADY BEEN REPLACED WITH NEW PARTS
- Spark plugs (replaced with new)
- Spark plug wires (replaced with new)
- Coils (replaced with new)
- Engine Harness (replaced with new)
- Injectors (tested and all worked good)
- MAF (got one from a C280 for dirt cheap)
- CPS - Crankshaft Position Sensor (replaced with new)
- All the fuses (including the one in the OVP) (replaced with new)
- Checked for air leeks.. nothing


CHECKED THE ERRORS WITH DIAGNOSTIC TOOL (PIN 8), AND GOT:
- ERROR 4 - Hot film mass air flow sensor
- ERROR 38 - Adjustable camshaft timing solenoid - open/short to ground or B+.

This was checked just after i swapped the new engine harness. Before and after swapping the car keeped the exact same symptoms. After reading I erased all errors.

Another thing to all.. this might help alot now that I remember it.. 2 months ago I took the fuel rail out when testing the injectors.. cranking it up, cylinder 5 was always giving gas, and was not respecting the firing order.. swapped injectors and still was cilinder 5 doing it. Having the injectors checked and new Wiring harness what could be it?

Here is a video of the car starting.. no weird dashboard light up..



Here is a video of the actual problem.. as you can see when in Drive/Reverse I have a rpm drop.. also.. when I hit the gas hard the car shakes alot (what video quality and my phone shaking), if done slowly no problem what so ever.


After reading many posts about this M104 engine and spending a couple thousand on it I am in despair..

Also a few other things I alredy checked..
- Cruise control works, so I think we can rule out the Electronic Throttle Body. (I think)
- When running, got 13.80 volts, i think its within a nice range.
- When running, I hit very sloly the OVP, nothing happened (looking for some rpm change, finding the culprit that way)
- When running, I took of the MAF sensor, rpm increase/decrese in neutral/park, when in gear same symptoms (same principle of what I did to the OVP, trying to reduce possibilities)
- With key in position 1, I hear the fuel pump working, so we can rule out that as well (I think)
- Took out OVP - it collapsed in my hand (somebody had previosly opened it), cleaned all the pins in it and I put it back together.


Any suggestion would be aprreciated.. as I said before I spend quite a few chunks of money in it and the problem is exacly the same..

Thanks

junkyarddawg

Has this car ever ran good for you and if yes then what happened? Like any recent repair work and then this is happening? I would look very carefully at the flywheel segments and make sure none of them are damaged. You can use a mirror and a flashlight then slowly turn engine from front bolt to see if flywheel is damage, bent teeth. Also you can test wire harness from #5 injector plug to ecu and make sure there is not a short to ground or cross continuity. If harness is not too brittle you can wiggle the harness a little while you test it with ohm meter. Hope something helps.

GuilhermeRocha

Thanks for the reply.. yes it worked good for the first year I got it.. then started doing this.. the wiring harness is brand new, and after replacing it the symptoms stayed the same. It's a very weird thing to happen.. and even more only when engine is hot!