Hi all, hope you are all keeping safe.

soooooo, car has had an erratic idle for some time and I’ve just got around to looking at it

it hunts quite a lot when cold. Assuming this is the ISCV (which actually was a new one from Ford and has down about 4K on the car, albeit over 10 years 🙄.) I have had this car for 18 years now so know it quite well but this one has me baffled.

When hot. And I unplug the ISCV, the revs rise 500 rpm. I could understand if they dropped (with it being an electromagnetic valve) but not rise. Give the throttle a blip and it settles down most of the time to 950rpm. I have previously changed the TPS thinking this might be it - no luck.

also one you unplug it and the revs rise, when you plug it back in, they do not automatically drop again without a throttle blip.

I did the ISCV setup (from autodynamix website) And the springs seem fine, they return the valve (on a bench) to closed. It’s free and doesn’t seem to be worn (I cleaned it to be on the safe side).

is there something else (apart from idle screw and throttle) that can raise revs with the ISCV unplugged?

there are also no air leaks.

many thanks

 

It seems odd that when you dc, the speed increases.

Have you tried cleaning the valve? It does seem from what you are saying that the valve may be the issue.

Martin