Pelican Parts Forums - engine revs up/down when warmed up

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engine revs up/down when warmed up

Once warmed up '87 325E engine goes into continuous cycles of engine revs going up then down in fairly rapid succession. Repeats about every 1 to 2 seconds.

Any ideas about the problem ?

Thanks
Brendan

Sounds like the Idle Control Valve (ICV). I would remove it and clean it out (internally) with some throttle body spray cleaner.

Bear,
I will give it a try this weekend. Thanks for advice.
Brendan

Today, I finally got around to removing the ICV and cleaning it internally. I actually used carborettor cleaner. When I replaced it, it did not immediately fix the problem. however after I drove the car for about half an hour I noticed that the car was revving at a lower RPM. I think the carb cleaner I used was actually clogging the ICV somehow and it evaporated when the engine got warm, thus clearing the opening in the ICV. (My theory!) I should have bought some throttle spray!

The car now revs at 1000 RMP when stopped in park and 500 rpm when stopped in drive. Is this correct ? I tried to adjust the ICV but the screw cannot be adjusted any lower.