E30 Zone

I've been bashing my head against the wall on this one quite some time now. I've got an M20 that is idling high - 1000-1100RPM. Things I've tried so far:


Clean AFM, ICV & Throttle body.
Checked for vacuum leaks everywhere and replaced old pipes
Replaced blue sensor
Changed the connectors that go the fuel rail under the intake.
Tried replacment AFM
Tried replacment ICV
Checked TPS, cleaned it out as it was gunked up

It's got new fuel pump and filters, plugs, ht leads.

If I let it idle for a while and rev it up a bit, as the revs drop they go down to about 900rpm then back up to 1000. The engine runs smooth otherwise.

What else can I check?

Have you tried backing off the idle control screw

parksie wrote:idle control screw

??? ICV, so the screw sets the minimal opening of the TB... not really to play with, I think

When the TPS gets gunked up and stops working , the engine will start to idle erratically and possibly cut out, a meat head appears with a screw driver and a hammer and magically 'fixes' the problem by winding up the throttle stop screw.
Cleaning out the throttle switch and fixing the initial problem will not cure things until the throttle stop is correctly adjusted. On opening the throttle with the engine turned off you should hear an audible click(if the switch is clean and working), adjust the throttle stop until you hear the click just off idle. This advice is good assuming no one has loosened and moved the throttle switch !

Click is fine on the TPS used a multimeter to check it as well - and also the full throttle position.