Idle problems

[irish]

I have a '87 325 ic. Today the car began to idle strangely. It cycles from 2000 to 1500 rpms and back to 2000 over about a 1 second period when I sit with the clutch in or with the engine out of gear.

If the car sits off for a while, when I start it, the engine goes to 2000 rpms for a short period until the engine warms up a little, then the car starts to idle as described above again.

When I drive it, it seems to drive fine and cruises ok until I pull up to a stop sign and let it idle...also it does jerk a little at very ow speeds in first gear when little or no gas is applied.

Does anyone have an idea what could cause this?

 

[epj3]

Bad idle control unit and/or idle control valve.

Anyone who says "cold start injector" is wrong, since the M20's (the 2.5l) don't have cold start injectors.

http://www.unofficialbmw.com/repair_faqs/idle.html should help. I get the same problem when it's cold out.

 

[Mr.W]

Also check to make sure you are not loosing vacuum. Lose of vacuum could be from engine oil leak or rip in intake system. How many milies/km?

 

[irish]

91870 miles, no oil leak .... intake system looks ok,,,

 

[bichmgnt]

I found a broken wire on the cable to the ICU when I had those symptoms. Found it at the plug to the ICU.

Steve

 

[chris knox]

try ur idel control vaule, u can pick a cheap 1 up from the breakers.

 

[BmwBoy19]

yo i had that same proble an it wuz a fuse check all of them

 

[epj3]

try ur idel control vaule, u can pick a cheap 1 up from the breakers.

Dude, no offense, but idle control valve has been named twice already... try reading the threads before you post.

 

[Mr.W]

Ha Ha