Idle hunting/ idle control valve, NEED HELP!!

[Jimmylucas426]

Hi all!! Can someone please help. I have a hunting issue on idle. At 1st it would hunt between 1 and 2 thousand RPM. I have done a flash test and the code come up was (no known faults) so I unplugged the idle control valve on the right hand side of the inlet manifold at the back. The engine ran the same. So I took the idle control valve off and it seemed a bit gunky so I gave it a good clean put it back together and put it back on. The car now sits at 1500RPM when warm and doesn't hunt. I've checked all vacuum hoses and they are all ok. So does this mean the idle control valve is faulty? And can someone point me in the right direction to a parts dealer or shall I just use nissan?

 

[PobodY]

To be honest it sounds like you fixed it by degunking the IAC valve... but now the idle is too high. - Have you tried adjusting it with the screw?

If everything else is fin I'd guess it's an air leak. - What BOV do you have; is it possible it doesn't seal at idle?

 

[stevepudney]

You must remember it's a 20+ year old car.

You'll probably find that the PCV has been gunked up for years and previous owners might have made adjustments elsewhere to try and correct the idle, like the idle speed adjusting screw as Mentioned above. There are also a whole bunch of small hoses around the back of the plehum that if not already renewed will be 20 odd years old, hard and almost definitely leaking. Have you checked the timing ?

 

[fubar andy]

The car now sits at 1500RPM when warm and doesn't hunt. I've checked all vacuum hoses and they are all ok. So does this mean the idle control valve is faulty? And can someone point me in the right direction to a parts dealer or shall I just use nissan?

Welcome to my world, mine idles at 1500/1600 for the last 5 years, going to pull out the idle control valve one of these days and clean it, then adjust the idle and hopefully that should do it.

Try what Pobody has said, if that don't work, revert to what Steve says it's old and you'll prob's have a leak round the back on the engine somewhere...

...not the end of the world, I've got used to it!

 

[Jimmylucas426]

Thanks for the replys guys. Right the idle screw if I adjust it, it only raises the RPM doesn't lower it. Also when it's just warmed up it does hunt but stops after about 5 mins of driving and sits at 1500/1600rpm. I haven't checked the timing but from what I have checked of all the hoses they all seem ok. But will go over it again.

 

[Jimmylucas426]

Also I haven't got a bov the hose that comes off the manifold had a bov on there but wasn't plumbed in, so i took that out and blanked it off.