Revs going up and down when idling.

[tarino]

Folks,

I inherited a 320i E30 (my first BMW). When stoped at traffic lights, revs go up and down between 500 and 1000. I've also noticed that on a cold morning, it idles at over 1200. It returns to a little ways below 1000 after a short while. Also head lights and the dash flicker. I took it in for service and the revs thing went away for a few days.The mechanic said he cleaned it up a bit. For the lights flickering, they said the alternator regulator was faulty. Apart from doing around 250 miles/ 55Litres in neghbourhood errands, it seems a good runner. It has done "90K" (note quotes). Would it cost much to fix or should I sell to get another e30. What is the best e30 to own? for a newbie.

Thanks.

[e30maystar]

revving up & down could be idle control valve, spray some wd40 or something like that in it, or possibly adjust the butterfly on the throttle body, someone with lots of knowledge will probably come along in a minute & tell you exactly how to cure it, but this worked for me

[Brianmoooore]

DO NOT adjust the throttle butterfly and check that no one else has in the past, and DO NOT spray WD40 into the ICV. Use carb cleaner to flush through the ICV, but I suspect your mechanic may have already done this.
When you move the throttle butterfly off its stop you should hear a faint click from the throttle position switch on the bottom end of the throttle spindle. To be sure you need to remove the plug from it and check for the switching action across two of the three terminals with a test meter.(The third terminal is for a second switch in the TPS which operates near wide open throttle). If there is no click, then either the TPS is dud or it is out of adjustment.
If the TPS is OK, then the next thing to try is a different ICV.
Check the big rubber air hose between the air filter housing and the throttle body for cracks and splits.( Easier to get at the TPS if you remove this first. New one about Ԛ£10 or so from dealer.
Altenator fault diagnosis sounds about right
Unless you can confirm it has been done in the last 40,000 miles, then get the cam belt changed ASAP.
Nothing wrong with 320s. You get that super smooth straight six engine and glorious sound, but unfortunately they are every bit as thirsty as 325s, and don't have a great deal of performance ( and slightly inferior handling ) over 318s because of the extra weight. Insurance will be a bit less than a 325 though.
90k miles is nothing for a M20 engine. Even if there's been a '1' removed from in front of this, it should still have plenty of life left.

[Simon]

Eeek WD40 in the ICV!

[Guest]

Guys hate to ask a stupid question, but what does ICV stand for and where exactly is it?

[kidsinister]

Idle control valve.

[Simon]

And it's located just of the pipe that runs from the Airflow meter to the throttle body, it's silver and black with an arrow on it and a wiring connector.

[Brianmoooore]

And it's inards are fragile.

[Demlotcrew]

Like i said before the M42 has a auto learning TPS,

[Simon]

Like i said before the M42 has a auto learning TPS,

? It's not an M42 though!?