Idle

[siksII]

Lately i have been noticing that every so often, say when i am sitting in traffic, the idle will sit at about 1200rpm for maybe a minute, then drop back to normal again. I havnt experienced this before as far as i can remember.

Also, in case it might be relavent, the idle issue has been happenning since i have been using the air con on a regular basis, but only happens when the air con is off.

its an r33 gts-t..otherwise everything is perfect.

Anyone know why this is?

[blind_elk]

Try cleaning the AAC valve (on the back of the plenum chamber). It might be sticking a bit.

[Ronin 09]

what exactly does this AAC valve look like?

[siksII]

thats the small black plastic thing on the front end of the intake plenum right? with tubes going into and out of it?

That was squeeky clean, i had it out a few months back, so i dont think it would be dirty yet..

Does my description match that of the AAC valve ur talkin about?

[druzilla32]

does it do it about 2-5min after a cold start?

say you cold start it, then drive for 5mins not stopping, then you have to stop and let it idle.

If it is that then i would say it is normal as my 32 does that and its probably just to warm the engine up a bit quicker or something...

just a thought

[sewid]

If its happening on hot days it could be the clutch fan engaging to move air through the radiator.

Does the temperature gauge sit much above half way on your car?

[siksII]

thanks for the replies to far..

but

druzilla32 - i never drive the car without letting it idle for at least 5 minutes when cold... it usually happens when the car has been on for less than 30 minutes i would say..

and to sewid- it is not the clutch fan engaging, when it engages there is not much difference in the idle compared to the high idle i am talking about, the temp gauge never reaches half way, always sits slightly below half way once warm.

[druzilla32]

maby the plugs then. Heat range is wrong or something...

I had NGK iridiums in my car.. took them out preety quickly tho.. It would idle at about 1000 when cold then 1800rmp when it was warm.

Your problem doesnt seem quite as serious tho..

There was also other promblems with theses plugs tho. eg, wouldnt hit boost, wouldnt rev over 2100rpm.

[siksII]

maybe thats it, because just a few months back i changed the plugs from (fouled) platinums to ngk iridium. But the heat range is correct...i think they are 6 or 7..the same as before.

I have not gapped them though, so they are 1.1, cuz i didnt want to damage them.