Greetings, all-first time posting here, but long time member over on Bimmerforums. I've been having a similar problem w/ my car (95 318i m/t, 215k and counting) for going on a month now. I've just been living with it until I find a solution I can bite my teeth into, but I wanted to share my experience because it's a little different from what's being described here and maybe it'll shine some light on what could fix either or both of our problems...
Similar to what Hunsbergring is describing, my car won't rev past a certain RPM, but where my problem seems to differ from Huns' is that mine is seemingly completely temperature related. I.E., from a cold start (on a cold morning, say 30* ambient), it usually will top out at 2500RPM; however, as the engine warms up, the rev cut will gradually rise until it finally will rev all the way to ~6300 when the engine is at normal temperature, and that will remain the case until the engine cools off again. As w/ Hunsbergring, the "cut" feels very precise and computer-controlled; the engine runs strong all the way up to whatever RPM it cuts out. Other than this, I've noticed absolutely nothing out of the ordinary as far as performance is concerned. The stomp test is clean, haven't ever had a CEL, so I'm kinda stumped...
It all started after I decided to replace my front main seal and the gaskets on the oil filter housing. During that process, I (unfortunately) had to replace my alternator due to one of the studs breaking off my original one. Other than this, every part I put on the car came off the car, and I've triple checked my handiwork and can find no loose ends there. The only thing I can knowingly say may have something to do with this is the fact that I noticed while it was removed that my harmonic balancer is slightly out-of-round due to a crack in the rubber at its' base. I have another balancer out of a junkyard car that appears to be in good shape, but I need to order another crank bolt before I can replace this. My thought there is perhaps the CPS is getting a bad reading due to the balancer wobbling, but I don't understand how this could be anything temperature-related :confused: Unless it's something as crazy far-fetched as the wiring continuity changing w/ engine compartment temperature, or the rubber on the crank pulley becoming more pliable and it wobbling less once the engine is warm. But both of those seem to be so far-out in my mind...I can't imagine the tolerances are close enough for either of those theories to have any merit...
As with this thread, people on Bimmerforums suggested O2 sensors, IT sensor, MAF sensor, fuel issues, etc. etc. But seeing what all Hunsbergring has tried, I'm hesitant to just start throwing money at some pretty expensive sensors. Granted, I haven't changed anything since this problem started and it's been consistent for over a month now.
Any suggestions are appreciated.
