3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
That sounds like a faulty idle control motor, make sure you don't have any intake leaks, especially around the flex sections of the intake boot (very easy to miss there). Then unplug the idle control motor and see if it jumps up and down. If the idle stops fluxuating, replace the motor. If it's still fluxuating you may have a dead spot in you air flow meter.
I have a working Idle Control Valve taken of my 1989 E30 318i M40 Engine, T-Shape Bosch if anybody wants it. I thought it was problematic and I bought a new one cause I had bad idle but in the end the air flow meter needed adjustment.
That Idle Control Valve is touchy. I was cleaning a bit under the hood and I guess I bumped it because when I started my car up, it did the 600-1200 idle thing. Good thing I know what to do. disconnect, wiggle, reconnect. Good as new!
__________________ '86 325es (TURTL3): PJ peetsa hawler
'87 535is (BADWATER): almost done... really.
'86 325e (GRN HLL): DD/show/rocket
'04 x3 3.0i: Wife's Bimmer (manual, woot!) My BMW Blog
It's called the air flow meter because it measures the volume of air with a flapper door not the actual mass as the mass air flow meter measures the mass of the air by measuring the amount of electrical resistance the heated sensor wire has. Less air hotter the wire is, more air cooler the wire is.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.