skibumajg

So I have the common hunting idle problem with my 91 C4 w/LWFW. I removed the ISV and cleaned it thoroughly. When looking inside the gate was partially closed which looked like it should based upon the pictures I saw on the forum. My question is how to I know if the ISV is operational? Should I be able to move the gate or another part? The gate wouldn't budget but I wasn't using much pressure for fear of damaging it. Thanks.

Navaros911

You can hear and feel it click... I believe with the key in the on position you can test it by unplugging the plug.

On the bench I think you can test it as well with 12v power.

Plenty of threads on this... try the search function.

Also check your AFM (Air flow meter) and FPR (fuel pressure regulator). Try the search.

ja78911sc

Wire a 9 volt battery to the ISV after you remove it from the car. It will spin internally which confirms it is operational.

Zingari

Might also be worth checking the age of your oxygen sensor in the exhaust. I renewed mine and it appears to make the engine run a lot smoother and steady on tickover

sml

Yes .. the little small 9V batteries have enough power to give it a click.

skibumajg

Thanks for the help. The 9V did the trick.

ramans

what's the pin out on the ISV for wiring it on a bench? I'd hate to reverse it or get it wrong.