FIXED: Stuttering at 3k RPM.. has anyone figured this out? --- VIDEO INSIDE

[Nairb]

Received a comment on youtube saying it was potentially the cam lobes.. I had the valve cover off about 4 months ago and all the cams looked good.. guess I can check again. I'm taking this to a local BMW master tech probably tomorrow to try and troubleshoot (he's a 'buddy' and has no problem helping me) because after talking on the phone for over 30 mins even he seemed stumped..

I'll report back, and hoping it's not my cams!

[CircuitMonster]

my car's situation is not quite the same as yours but while driving for a bit i lose all power and as letting off the gas power came back. today finally the car died on me with no power even with throttle pushed and now will start but will die off. looks like the fuel pump finally died. the loss of pressure would was causing the car to boggle down and finally die. hope mine gets fixed tomorrow and hope that maybe this might be the start of what you have so you can fix it. 318is FTW!

[Balleristic31]

You might as well try it dude. I hope you get this resolved soon.

[Nairb]

Ok, I am having another hunch here.. could it possibly be the fuel pump? I just really don't think it is the crankshaft sensor.. there are no other symptoms, and the car runs BEAUTIFULLY up until 4500-5000 RPM.

Could the fuel pump be dying and not sending enough fuel/maintaining pressure for higher revs?

I have not replaced the fuel pump in this car yet, not sure how old it is.

[Nairb]

...I have replaced the AFM and I swapped out the ENTIRE DME which had a stock chip. Neither of them helped my problem.. (see post #22)

[mr ilia]

I will say again, this is either AFM or the DME chip. I have stock "175" chip I can let you borrow. I also have a spare AFM, only for borrowing. If you pay shipping I can send it over....it will Comming from Canada so duties/taxes may have to be paid at the border.

[Nairb]

I just want to say, this is like a fucking curse. Right when the powerband kicks in the engine stutters and you either have to shift or let off the gas.. I want to keep my m42 but my patience is wearing thin.

Any way, thanks for all you peeps trying to help me figure this out. I am definitely going to keep posted.. if anyone has any more suggestions, please feel free to give me some insight!

[Dj Buttchug]

not sure if stock motronic is limited rev-wise

[Leo_328i]

Ok so.. still have not been able to figure this out unfortunately. The car is now hitting a wall at 5k hot or cold.

I replaced the AFM, tried a new DME with stock chip (thanks Ryann) and also checked the connection for my o2 sensor.

I have not replaced my crank position sensor.. maybe that could be the culprit?

If you've tried DME and AFM then crank sensor sounds legit.

Perhaps the crank sensor is faulty is is making the ECU think to activate the rev limiter. In the video the tacho needle doesn't bounce off at 5000rpm it kinda goes all over the place for a bit. So perhaps at that engine speed the crank sensor isn't able to send a signal that the DME can understand and then the DME freaks out and activates the rev limiter.

That seems to make sense to me.

[Nairb]

Cleaned the ICV a couple months ago.. also, my idle is solid.. would an ICV effect high-revs?

[siazul]

Was gonna say AFM but I guess Id be wrong, had similar issue a couple of months ago and changing it out with an extra I had fixed it. Maybe you need to clean the ICV?

[Nairb]

Ok so.. still have not been able to figure this out unfortunately. The car is now hitting a wall at 5k hot or cold.

I replaced the AFM, tried a new DME with stock chip (thanks Ryann) and also checked the connection for my o2 sensor.

I have not replaced my crank position sensor.. maybe that could be the culprit?

[Nairb]

Doesn't really start hard when initially starting.. probably revs to like 2k and then falls.. no CEL at all and no codes thrown during a stomp test.

IMMAJACKUP.. no idea what exhaust setup it is.. PO put it on.

[immajackuup]

op what cat-back you have?? sound pretty nice.

[mr ilia]

I was going to say to try stock "175" chip, as well AFM.
Try borrowing the another chip somewhere or buy "performance chip" from ebay for about 30.00.