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e21 m50 high idle

Posted: Sat Mar 07, 2015 5:07 pm
by ducky1
K I have a m50b25 I'm my car and it has started to do my nut in.

It starts no problem at all but it idles about 1500 rpm to 2000 rpm when cold for about 2 min and just shuts off then. Then I restart it and it idles between 1000 rpm to 1500 and shuts off. If I keep the revs up a tad it will stay running. I have tried the air flow sensor and that is perfect. If I disconnect the tps it ticks over perfectly so is this the problem I'm not convinced that it is. I do know that I discarded the charcoal caster and that plug is doing nothing should I have it plugged in.

Re: e21 m50 high idle

Posted: Mon Mar 09, 2015 11:22 am
by nas80
air leak for sure

usually its that pipe going into the intake from the idle control valve.

when you are disconnecting your MAF it will run a lot better - because you are putting it in safe limp mode and its not using the sensors.

Re: e21 m50 high idle

Posted: Mon Mar 09, 2015 7:49 pm
by ducky1
nas80 wrote:air leak for sure

usually its that pipe going into the intake from the idle control valve.

when you are disconnecting your MAF it will run a lot better - because you are putting it in safe limp mode and its not using the sensors.

Ya I was thinking it was a air leak but could not hear anything. If I disconnect the MAF it will not tick over at all it cuts out immediately. If I disconnect the tps it ticks over perfectly.
Cheers for the reply

Re: e21 m50 high idle

Posted: Mon Mar 09, 2015 10:22 pm
by nas80
Coukbeld be a dodgy tps I suppose. You best off plugging it onto a diag.