325e idle jumping up and down

[ma.jomaa]

Hello All,

I'm new to the forums and posting this thread to try to help my brother get his 85 325e running properly. the symptoms are

-Idle going up and down between 600-800 rpm
-Exhaust fumes smell really rich
-According to my brother he's getting really crappy mpg
-Missfire when accelerating until 2000-2500 rpm


I've never owned an e30 as I've always been a pre e30 era guy, but I'm mechanically inclined and would like to help him avoid a shop visit. Any input to what the culprit maybe and how to fix it would be greatly appreciated.

Also do you know of any good shops around san fernando valley area that won't charge an arm or a leg to diagnose the problem (incase we can't fix it).

[Cephas]

I would start by checking the throttle position sensor. After that, afm as well as coolant temp sensor.

[Andy.B]

I would start by checking the throttle position sensor. After that, afm as well as coolant temp sensor.

This, and the idle temp switch.

[dougie30]

My 86 325e had the exacts same problem. Its a vacuum leak, mine ended up being the little cold start valve plate. It was missing 2 bolts so every time I stopped it would move and cause the same ideal issue.

Save your self a huge headache and just do a smoke test.

[e34_spangler]

pull the icv connector off when car is running if the car doesnt jump to around 2k then your icv is bad and thats causing the jumping idle my E had a jumping idle and a icv fixed it all

[ma.jomaa]

Thank you guys, I've been away for a while but will check all the stuff mentioned over the weekend and report back on how it goes.