I have a 380 SLC that won't idle unless I hold the airflow sensor open a tiny bit with my finger. Once it's running, the plate seems to open and close just fine with the throttle, but it will die at idle. Also, the manual says there should be .1 to .2 mm clearance all around. This one appears to be tight all around. I already had the whole unit off to reattach a vacuum hose on the throttle body, and couldn't find any other vacuum leaks or anything that would explain this.

Any ideas? Thanks!

That 1/10th of a mm is a pretty tight clearance between the edge of the plate and the slighty larger diameter body. If you had the unit off the car and put a flashlight behind it, "you'd see the light", so to speak.

That slight depression on the plate means you're lying to the fuel distributor about how much air is passing by the plate (that or the teeter toter the plate moves on is damaged so it won't move on its own; which is unlikely if it's really easy to move).

I think your next step is probably to test the amount of air going through the idle air valve (and if the valve is working) and to look at the fuel control pressure.

Both tests are in the manuals and also in posts in the archives here.

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/

Okay, I found no voltage at the plug on the idle control valve, because there was no voltage at the supply to the idle control unit. The search goes on. I can only lay on my back under the dash for so long.

I do understand the airflow sensor plate, and now the idle air valve, but where does the idle FUEL come from? Is it ported through the idle air distributor? There is a fuel line connected there through the cold start valve, and air pipes running to the injectors, but I couldn't find much of an explanation in the manual. How does idle fuel get metered?
Thanks again for any help.

What exactly is/was the symptom you are trying to cure?