ICV staying on

Post Fri Jun 08, 2012 9:58 pm

Has anyone experienced this ? When I remove the key from the ignition the ICV is still buzzing. I've tried another and it's the same.
1990 (F) m20b20 I've plugged it out to prevent battery drain overnight.

Post Fri Jun 08, 2012 10:56 pm

The icv is turned on by a relay rather than direct from the ecu is it not? (dont have wiring diagrams to hand)
If so could be the relay stuck on.
Have you checked to see if anything else is still powered after switch off?

Post Fri Jun 08, 2012 11:24 pm

ICV gets its power from the DME relay, so if that's latching open then all sorts of stuff will remain powered with the key out.

Remove the DME relay and hook a test bulb and between pin 86 and ground of the DME relay socket. Test whether it glows with the key out, or only with IGN switched on.

Post Fri Jun 08, 2012 11:39 pm

Thanks for that chaps, on reflection I did change the dme relay earlier today, the engine was very reluctant to start from cold, I changed the fuel pump relay too and the engine started properly.
Will try a 3rd relay in the morning and see what happens.

Post Sat Jun 09, 2012 8:57 pm

Following more failed cold starts this morning, I tried another ecu. The motor fired up immediately and took a few minutes to settle down (as per). The icv switched off a moment or two after the ignition was switched off, so all good now.
For some reason the other ecu was keeping the dme relay latched with the ignition off, I wonder is it easily repaired or just good for the bin ?