Idle control valve

[oldred]

I have heard it is possible to disconnect the idle control valve on the V8S, has anybody run their car with one disconnected? I am having problems with my ICV despite having stripped and cleaned it. It now runs better, but still occasionally will not drop to the correct tickover. I have pulled the plug off the valve, and it drops to 800 RPM immediately I lift off the throttle. I did not want to run with the plug disconnected if it was going to cause any problems. I understand the valve should allow the revs to drop to approx 1100-1200 rpm to clear unburnt fuel from the exhaust, and after a few sencods should drop to 800RPM. Mine will sometimes stick at 2000RPM, and will even run at 2000-2500RPM upon starting the car.

[andyf007]

I've had to run mine disconnected for some time with no ill effects, but mine's a V6. The valve is fed by the ecu to control the idle speed, so it's more likely either an engine temp sensor or the throttle pot that's dying (if yours has one). You will need it sorting by winter or you will find you have no fast idle when starting from cold.

Andy

[oldred]

Andy

Thanks for that, hadn't thought about the cold start.

[z_chromozone]

Did you also clean the hole that the thing sits in, a bit of curled up rag usually does the trick. I had to use a rounded stick to get in there properly, a bit of white spirit also helps. Also, don't forget the teflon tape and not to over tighten as it affects the seating of the valve.

The only other time my revs have failed to drop is when I connected the enrichment injector to one of the cylinders and vice vesa (after my rebuild). I spent ages finding that. If you have not disconnected the injectors at all then you can rule that out

Z

Also, check for leaks in the vacuum system and that all pipes are conneted / not perished.

>> Edited by z_chromozone on Friday 23 July 09:57

[kentishS2]

My V6 also revved high and would settle after approx 5-10 secs to normal idle speed. A new ICV sorted the problem out.

[oldred]

Thanks all

I cleaned the old ICV last weekend, and it seemed to improve the problem slightly, but it seems ever so stiff to move, so it could be on the way out. It behaved perfectly when I visited the TVR dealer so they could have a cursory glance at it, but later on when I started the car it revved to 2000RPM and would not come back down

I understand ICV's are about £70 so didn't want to jump the gun and waste the money if it was going to be something else.

I'll give it another clean and ensure a good seal, then perhaps shell out on a new one if I get no joy.

Thanks for all the feedback, fantastic forum this one, but is a constant distraction from work.

Paul