bouncing idle, m10

[taiden]

Hey all,

I have a 1985 318i and the idle bounces over and over again from about 800 rpm to 1200 rpm. rrrRRRaa-rrrRRRaa-rrrRRRaa-rrrRRRaa

It's absolutely infuriating.

I tried swapping out the AFM and no luck. But I have no idea what the condition of the used AFM is.

[AndrewBird]

Sounds like you need an new idle control valve.

[Holland]

^ and that is exactly why I don't fix mine. I have the same issue but only when I switch the A/C on, so I'm not really bothered to fix it seeing the price of a new ICV is through the roof.

[taiden]

Time to put a v8 in it I guess

[AndrewBird]

You might try cleaning it first. Pull it out and spray it down with carb cleaner. Sometimes they are just dirty.

[lennon]

smoke test and report back

edit:... when all leaks are repaired.

[taiden]

Just FYI for everyone. I have already sorted out the vac leaks and already cleaned the ICV... come on now, give me a little more credit than that. ;)

As it turns out, this issue was solved by unplugging the idle speed relay and plugging it back in. I suppose there was enough corrosion to cause issues.

Idle is now steady but it is high. I am just about to set the ICV using a multimeter as outlined in the bentley manual.

Thanks all for the help :)

[taiden]

Alright so idle is now steady, but it is high. I set throttle body clearance to 0.0015" and adjusted the ICV to it's lowest speed, and it is still too high. Penny trick it?

[jeffnhiscars]

The "penny trick" will confirm you have an ICV issue but it will only be effective in 1 situation (presumably at operating temp on an "avg" day) so at best its temporary and good for diagnosis. Try removing your ICV and put a wine cork in each connecting hose. If your engine only runs with a little throttle, then you know its your ICV...and if you do the penny thing dont let it get sucked in to your engine :-)