I have a 97 BMW M3 that's been giving me fits lately.
Car started making an intermittent sound coming from somewhere forward of the shifter that sounded like a spinning mechanism was binding. I isolated the trigger somewhat; if i was slowing down or the front of the vehicle was pitched forward (i.e. downhill) the sound would manifest. If i were traveling fast enough (i.e. 50mph+) the car would start interrupting spark, throw a crankshaft position sensor code and go into limp mode. If i kept it under 45mph i never had an issue, but i didn't push it. While the sound was "active" if I disengaged the clutch (pedal to floor) the sound remained unaffected.
the only feedback i got from the drivers seat was the noise and eventual ignition stuttering. steering wheel, shift lever, accelerator etc didn't pick up any vibrations / shimmies, etc.
I took car to the dealer today who came back to me with suspicious that the sound was on account of the throwout bearing and the stuttering was on account of broken teeth on the flywheel. They want $1100 to take the transmission off and investigate.
The throwout bearing doesn't add up to me at all since I never observed any differences clutch out or in. The flywheel is a little more feasible, but not explaining the forward pitch as the apparent trigger of my issues. The car also doesn't throw any codes or have any issues sitting on level ground and revving. I sat in my garage and revved to redline with no codes, noise or engine stutter, so that also makes me wonder about the flywheel as culprit.
When I dropped it off, I suggested the motor mounts might be a good starting point to inspect, but other than that are there any other rational faults to target before dropping all that money searching for ailments that don't quite fit the symptoms?
Car started making an intermittent sound coming from somewhere forward of the shifter that sounded like a spinning mechanism was binding. I isolated the trigger somewhat; if i was slowing down or the front of the vehicle was pitched forward (i.e. downhill) the sound would manifest. If i were traveling fast enough (i.e. 50mph+) the car would start interrupting spark, throw a crankshaft position sensor code and go into limp mode. If i kept it under 45mph i never had an issue, but i didn't push it. While the sound was "active" if I disengaged the clutch (pedal to floor) the sound remained unaffected.
the only feedback i got from the drivers seat was the noise and eventual ignition stuttering. steering wheel, shift lever, accelerator etc didn't pick up any vibrations / shimmies, etc.
I took car to the dealer today who came back to me with suspicious that the sound was on account of the throwout bearing and the stuttering was on account of broken teeth on the flywheel. They want $1100 to take the transmission off and investigate.
The throwout bearing doesn't add up to me at all since I never observed any differences clutch out or in. The flywheel is a little more feasible, but not explaining the forward pitch as the apparent trigger of my issues. The car also doesn't throw any codes or have any issues sitting on level ground and revving. I sat in my garage and revved to redline with no codes, noise or engine stutter, so that also makes me wonder about the flywheel as culprit.
When I dropped it off, I suggested the motor mounts might be a good starting point to inspect, but other than that are there any other rational faults to target before dropping all that money searching for ailments that don't quite fit the symptoms?
