e36 328i Intermittent Misfire

[HugoS]

Hi Guys,

My car had a very annoying intermittent misfire, especially once the car has reached operating temperature, and this happened even more often if the ambient temperatures were quite high as well. Typically it would feel like all spark/fuel was cut to the cylinders and then it would feel like it was running on 5 cylinders or even in limp mode. Diagnostics picked up no errors and no one could tell me w.t.f. was going on - so I did the following:

Replaced all 6 coil packs and suppressors - problem still persists
Replace CVV and all vacuum pipes - problem still there
Replace fuel pressure regulator - same nonsense
Test fuel injectors , compression etc. - no fault found
Replace coil pack harness - still

Took it back to indy - and eventually it was found this was caused by the vibration damper (crank pulley) that had failed ! Due to age the rubber damper has fatigued which causes the crank sensor to every now and again "lose" the pickup and in turn generate a misfire error to the ECU. So BEFORE you go and spend a LOT of money on other parts like I did - check this part out first

I really do hope this will help someone else with the same issue and save them money in the process - my car has about 400 000 km's on the clock so I guess it was due :rollsmile:

 

[Gizmo]

Don't know how the damper could have caused it unless the trigger wheel was wobbling terribly, I would have said crank sensor faulty.

 

[HugoS]

Hi Gizmo,

I agree, it was one of the items that we looked at (even though I had a new sensor) just to be sure. And to be honest the pulley is the last thing that I would've suspected - as the list of parts replaced probably indicates ! I am not saying this will solve everyone else's issue should they experience the same....but if it would prevent them to spend a lot of unnecessary money, that would be mission accomplished.
I assume it was wobbling excessively to cause a misfire/error - I never felt a vibration oddly enough. I am just VERY relieved that it is sorted it was driving me insane........and the thought of burning the car did cross my mind a few times !

 

[Gizmo]

Glad you came right and thank you for posting your results, I will be sure to add it to the list of possible misfire issues.:ty:

 

[hoosain]

Don't know how the damper could have caused it unless the trigger wheel was wobbling terribly, I would have said crank sensor faulty.

i agree with you i have never heard of a damper causing this problem
but hey you learn everyday
glad its sorted

 

[GPGrobler]

Hallo Hugo.

Thanks for the heads up on this one.

 

[Major]

Was the damper possibly chipped? Did you see the old damper?

 

[KevinZa]

The vibration damper is a tough rubber mould between the pulley and the actual crankshaft. This material eventually deteriorates with the torque effect between the pulley and crankshaft just like the rubber coupling of a propshaft. It allows a small difference in rotation or angular speed and this difference could possibly cause the crank sensor to sometimes erratically misread the timing mark.

 

[samman325]

Learn something new every day. I didnt realise petrol vehicles also had vibration dampers on the crank pulley. Thought that was only found on diesels.
Thanks for that

 

[HugoS]

Hi Major,

Didn't see the old damper - I doubt that it was chipped but not impossible I guess............oddly enough this missfire started not very long after the car overheated quite badly, so not sure if that could have damaged it ? (didn't blow head gasket or crack head thankfully) I took it to 3 different people and searched every forum I could find and couldn't sole the issue. Checked everything even had the ECU swapped