Help me fix my idle!

[Matty]

So i have been having a couple issues with my 85 318i.

First i replaced my head gasket and while putting it back together and reattaching the throttle cable i noticed (or thought) the cable seemed loose. So i adjusted the nut on the threaded part at the end of the cables cover. You know, not on the throttle body but where the cable's sheath ends at that bracket. The Bentleys says not to adjust this (I think) so i have since moved it back to where i think it was.

I put it back because the car was getting really jumpy at low rpm and kinda jumped through acceleration. It still does it but only slightly. How do i make sure it is where it should be?

Also i replaced my O2 sensor yesterday, i dont know how old it was. It seemed to run great after. But today while i was driving the idle started to get higher and higher each time i stopped, and then would be fine, then at another stop was high again. It went as high as 2000. I think thats as high as the icv will send it if its bad. How can i tell if it is the icv? Could the timing not have been set properly if the o2 sensor was bad? I have only timed it by ear because i dont have a timing gun (yet!). Any help would be great
thanks
-David

[Starmavin]

Test your throttle position switch first.

[Matty]

I can't find how to test that in the Bentleys, where is it?

[Starmavin]

On your throttle body. There you will find a three wire plug, unplug it and you'll see three terminals, the center is the common, you should have continuity between the center and one of the outer ones at closed throttle, then at wide open throttle you'll have continuity through the other and the middle.

[Matty]

I am going to check the TPS later today.

Does anyone think it could be possible that the O2 sensor i put in was bad, could it cause this to happen? Also, when i remove the vacuum line from my distributer when the engine is up to temperature nothing happens and i thought something was supposed to. I am quite lost on this one. I keep trying to adjust things but it either has no effect or it makes it worse.

[Starmavin]

The O2 has no effect on idle that would cause your symptom, it only tells the computer if the car is running lean or rich, that way the computer can make adjustments, the worst thing would be if you blew a fuse, however I'm sure that your O2 isn't heated so no worry there. The vacuum line to the distributor controls timing advance at higher engine speeds and load. At idle there will be no change if you disconnect the vacuum line...

[Matty]

Thanks for all the help. As always the true cause of the problem is never as nefarious as one thinks. The ground wire that bolts to the intake came off. It seems that it runs the ICV because now it hums away and the idle stays steady. It needs to be adjusted but hopefully that shouldnt be an issue.