E30 Zone

did the obvious and changed the idle control valve to no avail, so removed throttle body and removed cover from the throttle position switch it was caked in oil and was not adjusted correctly as it would not click back after throttle had been opened making the engine think is was on part load when in fact it was trying to idle, its much better now, there are loads of threads about this but what you really need to do is strip these components down and clean them out, the problem wont go away without it!!

Rough idle is very rarely anything to do with the ICV.
A worn and sticking ICV makes the car idle smoothly at various incorrect levels, and a faulty one often results in a wildly surging idle.
There are various reasons for a rough idle, but one of the principal ones is that the ECU doesn't know the engine is at idle. I.E. Faulty throttle position switch.

what is the easiest way to access the throttle position switch?

can it be accessed without the removal of the throttle body?

Also how would i know if it was dodgy, would i have to buy a new one to see if worked better?

Cheers Dee

Low_E30 wrote:what is the easiest way to access the throttle position switch?

can it be accessed without the removal of the throttle body?

Also how would i know if it was dodgy, would i have to buy a new one to see if worked better?

Cheers Dee

Take the big air hose off to get at it.
Use a meter to check resistance between the pins as you move the throttle.

with the switch being underneath the throttlebody id just take the body off the engine so you can see what your looking at and clean it and adj. it properly. also inspect the wires as just into the wiring loom of the three pin plug on my 320 throttle switch, i found a broken wire!!