MatthiasRex

Thanks guys- to clarify Bruce, the problem -seems- to be an intermittent short we can replicate by messing with the loom under the rear of the manifold- the cable from the ICV connector to that point seems fine and we have stripped most of the rubber back (and now re-taped) to confirm this. I think the short is in the 90degree turn just below where the 02 sensor plug would be (if it was a US/cat car).

The short is intermittent and I cannot in all honesty remember whether it was 33/34 or the 3rd pin- I suspect we will take out the loom and replace that wire and connector as the problem is intermittent now (ie stands to reason if we add-on we might not be able to entirely convince ourselves we got it right)- but would more than welcome advice!

The big question in my mind tho....
The above theory of an intermittent short to an otherwise brand new ICV- would it manifest as the issues I have experienced? Similarly when the idle is acting up if you disconnect the pulse train to the ICV it makes no difference. When the ICV is plugged in it is definitely getting power/pulse train but if I am working this our right in my head, the ICV must be staying open when shorted + be in default open when unpowered (or back-pressuring towards the j-boot) otherwise my bodge of blocking this air-pathway would not have worked!

Now starting to get a headache..

Brings me back to Spencer's helpful point which may blow this all out of the water- when cold at idle seems ok but as soon as have gone a few hundred yards and heated/pressurised things up a bit is when the problem seems to happen- ie would there be be sufficient pressure in the intake manifold to force air backwards down the ICV at idle when hot/been under load??

Cheers M

F18Rep

It works for me but if you're doubting, here are some loose ends...

How do you know this? I believe this would take either an o-scope or a dwell meter or possibly - maybe - holding your old ICV in hand while connected and engine running so that you can feel the ICV buzzing.

This was a good question but your pleasing click answer doesn't mean its working electrically. Best to continuity test it at the DME.

Setting the idle is fairly easy and since it disables the ICV, we might learn something (see WSM 24-17).

And BTW, I'm thinking that diagnosis plug pins mentioned in the WSM should be on the wires to be checked list since it can disable the idle control circuit. ... Bruce

Simonka

Have you ever solved this idle problem ?