Quote:
Originally Posted by eugene89us
Here is my original question from 12/27. My car currently has 16,000 miles and has behaved similarly since new.
Wanted to inquire someone with a strange problem. I seem to be more sensitive to it and am noticing it once in a while. The car (2018 328d) has 16,000 miles and still covered under warranty. However, given how infrequent and intermittent it is, I am unable to capture it on video, much less likely that the dealer will replicate it.
Since new, the car exhibited vibration patterns that were variable. Most of the time, when stopped, the car would either vibrate consistently (r-r-r-r-r) or have a slight change in sound and vibration patterns (R-r-R-r-R). I was thinking - maybe some accessory comes on and car changes the pattern. Almost like goes from consistent purr to a variable purr every other second. Nothing uncomfortable and you have to listen and feel carefully. When it goes into this strange tempo, if you barely touch the throttle to move the car at lower RPMs, sometimes (not always) it also feels like the car is shaky a bit - it accelerates in a tempo-like fashion. Give a good throttle and will feel no different than normal.
The funny thing is - if you put the car into neutral and back to D, the purring goes to consistent. So I don't think it is engine related. Doubt would be accessory related either, since that should have nothing to do with changing car to N and back. I was thinking maybe it does it during regen and placing in Neutral cancels regen mode, but I have no reason to believe that would have such an effect. No visible shakiness of tachometer needle.
ISTA D brings up no errors. I checked injectors and they all passed smooth idle test. Since I cannot myself consistently replicate the issue, I doubt dealer would be either. Anyone have any suggestions to check, including checks with ISTA? I am considering transmission adaptation next, but I am stumped as what this could be related to. Or would that be normal? Transmission shifts perfectly every time, nothing unusual since new. Upshifts are barely noticeable, downshifts are more noticeable but still smooth.
|
What you describe matches my experience. It can be subtle if you’re not sensitive to it and if not paying attention (or distracted) you might miss it but since it started a couple of years ago I’m sensitive to it now. I was able to capture it on my iPhone’s video a couple of times (video of the tach + sound of the engine surging slightly) and shared it with my service center but they had no idea and so, kept the car over a long holiday weekend and drove it a lot and were finally able to replicate the condition.
All the BMW diagnostics came back as the car is running (perfectly) in specs with the manufacturer and so, service center contacted BMW NA and they suggested the mass airflow sensor and so the service center replaced this component under warranty but the car still surges despite all these efforts. Intuitively, I think something is amiss but none of the experts or the computer diagnostics are able to pinpoint the problem. As it only happens when the engine is coupled to the transmission (idles fine in PARK just not in DRIVE), it seems like it might have something to do with how the engine and transmission come together at idle but only under certain conditions as it occurs or appears to occur randomly??