Idle = 1800rpm all the time.

[Doughnut]

I've had the battery out to do the intake manifold gaskets and ever since (bout 5 days) the idle has been at 1700rpm to 1800rpm all the time cold start in the morning to full operating temp in traffic, highway driving and all.....
There are no vacuum leaks.

I can only find answers specific to fluctuating idle.
Thanks for any help.

 

[echothreezero]

That AC relay? Cold Start Valve sticking? Search for high idle - I've seen a few answers on this before (maybe not this forum).

 

[E30m42cab]

When I had my M20, I had a high idle, and it took me a while to figure it out... all it was was the throttle cable had wiggled it's self out of the bracket on top of the manifold... I clipped it back in and zip tied it back onto the bracket (right at the butterfly for the throttle body).

 

[Doughnut]

That AC relay? Cold Start Valve sticking? Search for high idle - I've seen a few answers on this before (maybe not this forum).

Hmmm, but that valve would have only worked when the a/c was turned "on" bmw wouldn't have made it so that when you pushed the button it lost power and dissengaged? unless it was a "usually open" valve....

Ill get my voltmeter and check when it has power when the a/c button is depressed, I also have a vacuum gauge inline with the vacuum line that goes from the manifold to the vacuum throttle advance, ill try swaping it to another vacuum line in the morning.
Cheers.

 

[ldzpstnr]

Hey

More then likely your problem is from the Idle control valve or the Idle control module in the glove box. I have had 3 E30's now, and two of them had problems with there idle systems. When one of them goes out, the other one usually does to. The idle control valve is always open, but only partially. The Idle control module under the glove box monitors the engine speed and adjusts the idle control valve to hold the engine at one set RPM.

This is a common problem amongst the older E30's. You can test either part by using an OHM meter, but I do not know what resistance ranges the parts are suppose to be in off the top of my head. Or you can just remove the idle control valve, plug the holes, and start the engine. Doing this the car will not run at 1800ish rpm, it should not even idle at all unless you have a big vaacuum leak someplace else. This is how i tested my 85' 318i's idle control system.

Its odd that it would start doing this after you removed the battery. Also may want to take a look at all the grounds and electrical connections before you go buying new expensive parts.

Later