Engine surge

Okay, here is your idle control stepper motor:
https://www.aulro.com/afvb/images/im...2014/07/52.jpg
To remove it: you unplug it, remove the pipe in front of it, remove the two (tiny) bolts and just pull it out. Be careful with the gasket on it.

Once removed, it will look like this (only dirtier of course):
https://www.aulro.com/afvb/images/im...2014/07/53.jpg


This one is hard to tell if it's free as you cannot safely force the piston in and out so just spray inside it until the carburettor cleaner no longer comes off dirty and leave it in the sun to dry out for a short while.

Unfortunately the air bypass passages in the throttle body are quite small and can also get choked up. If you feel up to it, you can clean those out too but be careful not to leave pools of carb cleaner inside the intake (that said, blocked bypass passages will generally give a rough low idle, not surging - a sticky stepper motor can cause surging).

Quote:

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Originally Posted by Rage Over

As daf11e says to turn off the AC is correct. It's a bit strange, but just remember - the AC is OFF when the light in the top-right is ON. That doesn't make sense, does it? :D

Anyhow, I'm guessing from others' responses that you have a Thor motor (1999+)? If so, the stepper motor is called an idle air control valve in Bosch-speak and it can be found here (sorry for scribbling on your photo Paul):
https://www.aulro.com/afvb/images/im...14/08/1469.jpg


Up close, it is this little part:
http://www.bmwpartsweb.com/images/pr...4713-BOSCH.jpg

It's very simple to clean, just remove it from the engine and give it a good spray throughout with carburettor cleaner and give it a good shake in a twisting motion to make sure the valve inside moves freely.

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Thanks for such great detail. BUT mine is a GEMS engine, you still did a great job and now i know a little more about the other engine.

Hi Derpomz,
Someone else also pointed that out to me so I redid it for the GEMS engine (a couple or so posts afterwards).

Hope it helps!

I am having a bit of an idle problem when stopped at lights etc.

Could this be as a result of dirty injectors. If so whats the best stuff to run through the tank to clean them out.

I have read that it could also be a camshaft that needs replacing, this seems a bit drastic. I have also read that using top grade fuel helps also.

Any ideas.

Threads merged.


If you have a particular problem, keep the original thread going - that way you don't have 2 or more running at once with similar answers.