I had a similar problem, verified on the dyno. Timing would retard @ high rpm.
Turns out it was bad fuel. This may sound stupid and we're all guilty of it, but don't fill up at the cheapest station...
'99 Estoril Blue + Dove Grey ///M3 coupe
'04 Jet Black + Cinnamon ///M3 coupe
okk so i think i may half fixed the problem, or at least made it better. I changed my spark plugs this weekend, NGK BRK6E coppers (same plugs that were replaced, except those were gapped at .035...idk wats the best gap), gapped at .032. Cleaned the MAF sensor, played with its position....around 10ish oclock. Before that i checked my coil boots..all good. I did a compression test 200psi +/- across the board. Car is still running a little rough...prob a vaccuum leak from m50, and i think the throttle boot is starting to crack. Anyways ill do some more testing and more inspecting see if the problem is completely fixed.
Doug, I had the same problem. It turned out to be the cam sensor. I replaced it and the car has run great since. I suggest you look into that it just might solve your problem.
Jay
Jay, I actually replaced this sensor about 2 years ago. It failed while I was on vacation and I couldn't replace it till I got home. When the sensor failed previously, it actually threw a CEL. I suppose it's still possible that it could have failed again. Interesting...
Doug
'97 M3/4
i think i am going to replace them with the bav auto ones... if i am going to get new ones better get the ones that say "performance" haha
Doug-FWIW, when mine failed it did not throw a CEL/code. A friend of mine knows M3's pretty well and he made the call. Did you replace your with and OEM sensor? I think there is a voltage test you can do to see if it is operating with spec.
Let us know how you make out.
Yes, I did replace it with an OEM one from www.bimmerparts.com. As I said, it's been two years and anything could happen. I got on it today and there was no sputter. Go figure? I'll keep an eye on it.
Doug
'97 M3/4
It's an ohm test that you do to the crank/cam positioning sensors...
It sounds like your guys's problem is contamination of the combustion chamber, could be from a few things, starting with fuel, and of course your oil separator...if the oil separator isnt functioning properly, under high rpms, with all of the blow by gasses coming out of the PCV, it would suck in oil as well through the separator, straight into your intake manifold, thus contaminating the mixture...
When i had my turbo seals blow, thats exactly what was happening!
When boost kicks in, oil would get into the charge pipe, straight into the intake manifold, and contaminate my mixture, causing misfires/sputters...
Something to look at
Stan
Mods: Carbon fiber hood, headlights with angel eyes and 14000 Kelvin HIDs, blacked out/smoked tail lights and side turning signals, smoked front corners...and thats about it
Ohh...and some "bolt-ons" here and there........K&N air filter, m50 manifold, rouge trans mounts, a few V-band clamps, few silicon couplers....etc...etc....
http://forums.bimmerforums.com/forum/showthread.php?t=653809
Talked to a friend about this problem and he said it could be the fuel pump.. When I changed the valve cover gaskets there was no sign of running rich/lean on the spark plugs either.
99 Alpine/Gutted ///M3
98 Estoril/M-Technic cloth ///M3
- RIP http://forums.bimmerforums.com/forum....php?t=1191513
For the condition that we're experiencing, you would more than likely not see a rich or lean condition on the spark plugs. 99% of the time the car runs well but for the 1% of the time the car doesn't, you would probably not notice on the plugs. This of course doesn't rule out the fuel pump though. A fuel pressure check at ilde and under load should verify.
Doug
'97 M3/4
Haha i think your right...this weekend i had a problem with my car not being able to idle at all, i would have to try and hold the revs up, which made for a launch at every stop. Meanwhile my car had been idling like crap and finally just gave out. I went home this weekend ripped the m50 off, cleaned the icv, realized one of my connections had completely come undone. I redid all my m50 hoses lines...no the car has no leaks whatsover, idle perfectly, there is no hesitation and definetely no sputter. The car hasnt run this good in two years since i initially did a ghetto job on the m50. So everyone check for ait leaks if you have an m50.
Definitely a good point, although I don't have an M50 manifold.
Doug
'97 M3/4
^^ haha no sir... i do not have a ghetto M50 manifold swap...
Mine is actually pretty clean, since i do not have an oil separator anymore...the only thing i have is one hose from the manifold to the ICV and then another hose from the ICV to my charge pipe, and thats it
Click on the link in my thread for a more detailed installation if you care...its actually a good write up with tons of pictures when i was rebuilding/turboing my engine...anyways...
As of right now, i just dont boost anything over 12psi, as it seems it brings oil into the engine, causing it to sputter at high rpms because of the blown turbo seals...i have a new turbo coming in this week hopefully, so i will be changing it...
But yea, im planning on cleaning all of the oil out, rinsing the intercooler and i'll report back to see if that fixes my problem
Stan
Mods: Carbon fiber hood, headlights with angel eyes and 14000 Kelvin HIDs, blacked out/smoked tail lights and side turning signals, smoked front corners...and thats about it
Ohh...and some "bolt-ons" here and there........K&N air filter, m50 manifold, rouge trans mounts, a few V-band clamps, few silicon couplers....etc...etc....
http://forums.bimmerforums.com/forum/showthread.php?t=653809
i must add to this.
My car did this but i have AA software. I threw in a Walbro 255 Pump and still did it.
Changed plugs,
Still did it.
I havent noticed it it a while. Lets just see if it creeps back up.
Mods in sig.
It's funny you bring this up because I just looked at this thread the other day. I haven't taken the car up to those speeds lately to see if the problem still persists or not. The last time I did travel up those speeds, the problem didn't appear to be there, although I haven't done anything else besides change the plugs and the coil boots. I changed those items back when the problem first originated though.
I will give it a whirl this week and let you know for sure.
Doug
'97 M3/4
Ya i haven't encountered this problem since the start of this thread. I changed my plugs to NGK brk6e's, cleaned the MAF, and fixed my M50 manifold plumbing. Since then no ploblems whatsoever
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