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Rough Idle and Start-Up on BMW e81: Fuel Injector?


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Hi everybody, Last night I was going home when my vehicle abruptly lost all power and I had to have it towed. After a restful night at home, I checked on my vehicle early the next morning and discovered that it starts but has a harsh initial idle before settling down. Seems to vibrate when accelerated (video link added below). I performed a basic running test with ISTA and noticed that cylinder 2's fuel readings were significantly different from the others (picture).

I'm not sure what the problem is, but I removed the injector and it still ran the same, so I'm keeping my fingers crossed that it's just that. I'm crossing my fingers that it isn't rod knock.



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This noise reminds me a lot of diesel knock, however a few years ago on my N47 I discovered it was the fourth large end. It sputtered because the large end had so much play, throwing off the timing on that cylinder.

I would try removing the injector from cylinder 2 and plugging it into cylinder 1, starting the engine again, and reading the injector readings to see if they change.

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