slight misfire on first acceleration

[massive]

fitted a new engine recently to 1991 325i (the engine is an early 2.5)

Anyway, the car is running idle at approx 1000 rpm quite happily, but as soon as you touch the accelerator it kind of chokes itself and stalls/or nearly stalls and the revs drop down to 400-500rpm. Then if it does stall it takes a few turns to fire up again.

As a temporary ive adjusted the idle control to 1500 or so which is fine.....but i dont really want it idling at that speed.

Any ideas....

Thanks AGAIN

[Gwynleym10]

Have you check for:

Vacuum leaks (especially the big bellow from AFM - TB)
Cleaned AFM, TB, ICV with 7 cans of carb cleaner?
Fuel filter
Air filter


You are a naughty boy changing the idle, brainmooore will be very cross!

[FlappySocks]

Idle control? If you mean the screw on the throttle body, then you shouldn't adjust that. Idle speed is controlled by the ecu. The ecu needs to get a signal from the TPS (under the TB) to say your foot is off the throttle. You should hear an audible click from the TPS when you release it. If it doesn't (and it wont now if you have adjusted that screw! ), then you need to adjust/replace it.

Once you know that is working, check/clean the idle control valve.
After that…
Replace the blue temp sensor
Look for air leaks
Fuel pressure.

Stuart.

[DaveD]

should not you be idling at 7-800rpm rather than 1000 and might your high tickover be masking the fact that it won't run at that speed...try cleaning the icv...clogged injector ...electrics

[massive]

err yeah that screw! As mentioned it was temporary and the only thing stopping the car from cutting/stalling out pulling away at juctions etc

I'll put it back to how it was and clean everything mentioned above

The ecu was chipped and mapped to the old engine, if that makes any difference?!

[massive]

Ive done the above and all running smoothly. Thanks to DaveD, Flappysocks & Gwynleym10