Bad Idle When Warm

[singhters]

BMW 320I 1992 M50 ENGINE

My car idles bad when warm, when cold it idles perfectly but as soon as it warms up it starts to splutter like its going on and off the cylinder, 3 secs smooth and then 3 secs spluttering back and forth like that.

Also after I reset the ecu via taking off the battery and let the car idle for 10mins to get the settings back, I can hear it hunting is this normal ie its trying to find the idle again or not.


Before people mention some parts everything has been replaced apart from temp sensors thats the coolant one, engine and manifold air sensor as well as 3 coils, no air leaks as checked this no fault codes as checked this.

Could it be the coolant temp sensor as this and the engine temp sensor look corroded if so what effect could this hav on the engine.

any ideas and again please not do not mention any other parts as all have been replaced except for what i hav mentioned above.

 

[epj3]

Sounds like a metering problem...

 

[singhters]

Sounds like a metering problem...

Sorry how u mean by a metering problem can u explain in detail please.

thanks.

 

[singhters]

Ok when the idle is chugging I can press the heat screen button and it smooths out to a perfect idle.

What can this be ?, could it be that the engine is overloaded ? if so how, ecu or alternator.

 

[singhters]

Black soot in exhaust - Lambda ?

I disconnected the lambda and the car has idled better, I disconnected while the engine was off and then started the car and its perfect so I will say its the lambda at fault 1 because its 2nd hand and 2 because its universal and not original.

 

[singhters]

Fixed the problem, turned the icv the other way round the top pipe was a better fit for the icv and its idling and working fine no more bouncy rev and bad idle.