Overfuel on Idle

[Cyruz]

Right I know I have had various threads on my car being an annoying piece of crap but I'm getting towards the end of my teather!

The car is an 1987 325i SE with 140k on the clock. It's fine when being revved 1000rpm plus, even when cold but once it drops down to idle it becomes a pig (more so when it's hot). It will idle at 500/600rpm and shake the whole car and the engine sounds like it's about to cut a cylinder, then rev it a little and it's fine, then sinks back to bad idle again. It's also got really bad throttle responce from idle, the engine actually drops revs before it picks up with a small delay (very annoying when car almost stalls pulling away).

I've replaced:
AFM
ECU
Entire Engine Loom
Blue pin
Brown pin
ICV
HT Leads
Plugs
Dizzy cap + rotor
TPS

Now I took the TPS of the bottom of the throttle to clean up, I think that it may need adjusting, is there any specific angle or markings in which to bolt it up too seeing as it's been removed without being marked...! I can still hear it click on to idle setting but I think it still could be adjusted tighter!

Anything else obvious I should check (Have looked for air leaks). Garage couldn't find anything wrong with it either so I'm on my todd with this

[Cyruz]

Also forgot to add that if I disconnect the blue pin sensor the car refuses to start and cuts out when I disconnect it while it's running. The AFM kills the motor if thats disconnected while running and refuses to start without it connected, I only mention this as I'm sure it should idle without use of an AFM...!

[AlBoi]

i have the same problem with mine so i took out the idle valve and blasted some carbrettor cleaner through it till u can hear the valve moving more freely when u shake it. hasnt fully cured it but its miles better.
worth a try dont ya think
g'luck

[k]

Have you set the CO at the AFM screw to give 1.0% at exhaust using gas analyser etc?

[Cyruz]

The ICV has been replaced (I also cleaned it very well when I got it)...

As for adjusting the CO, if it's only really when cold that it runs rich adjusting the AFM would mess up the fueling over the whole rev range wouldn't it?

[k]

Not as I understand it, it needs setting up on tickover when hot with the gas analiser up the exhaust. The manual ( look in the Haynes in the front section where it refers to this adjustment) specifies a range of 0.5 to 1.5% in another section, so set at 1% and make sure you/the garage remove the allen key after each adjustment as it,s sensitive to the smallest bit off pressure. Recheck after final adjustment with a blip of throttle and let it settle The MOT pass is 3.5% or below so they won't be bothered about any figure between 0 and 3.5%. But know from experiece that this bit of the idling jigsaw is important in achieving steady idle and progressive transfer to main ECU control without the lumpy/jerky symptoms, and it therefore shouldn't affect the upper end.