Motronic Cold Idle Solved (for me anyway)

[dentist90]

Asjac... is that just when cold? I assume that 1100 rpm is your fast(cold) idle speed. Steve Wong was correctly pointing out that the Motronic achieves some of it's fuel efficiency by cutting off the fuel injectors on decel, ie. when you lift off while coasting the injectors will not spray until the rpm come down to 1000-1050 rpm. When you blip the throttle and release it there is a bit of a delay before the injectors activate again, hence it may drop to a lower rpm before catching itself. Sometimes when it does catch itself the engine really jumps hard... light flywheel and all that. Mine was bouncing up and down like that quite badly, sometimes 6 or 7 times before it settled down. The dirty ICV couldn't move fast enough to smooth this all out I guess.
If when you blip it it hesitates or stumbles ( doesn't actually rev up but dies out) it may be clogged injectors? Insufficient fuel pressure? The throttle plate is opening but there is not enough fuel to keep cold engine purring. Anyone else got a suggestion?

[Asjac]

No, this wasn't with a cold start, I had just turned it off from work and cleaned the ICV and when I was checking the idle I heard a weird sound? So I popped the throttle and it did this hiccuping thing. I thought the sound was the barn door, but I am not sure.

[troy jones]

excuse the newbie question, but I cleaned my icv out today and was wondering what that little black round connecter just below the icv is.

[CruiseControl]

Troy
Goes to a magnet pickup sensor mounted just off to the right side of centre at top of flywheel housing. Senses a single pin on flywheel. Wires connect to nothing else. Connect a frequency meter and you will get one pulse per RPM. Located to pulses at TDC - Z1 marking.
Paul

[troy jones]

thanks! another mystery solved