Author Topic: Hunting idle with Idle Control Valve on?  (Read 1841 times)

Offline leeroy_25

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Hunting idle with Idle Control Valve on?
« on: October 17, 2010, 09:19:51 PM »
Hi Guy\'s I have had my idle valve disconnected for a while as it doesn\'t seem to work? It is not the valve as I have tried 3 and they all do the same. basically when the car warms up the idle goes realy high and hunts like hell. So I am guessing it is either a glitch in the Apexi ECU or maybe a dodgy bit of wiring to the idle valve?
Anyone had this before and cured it?

Can someone confirm what the two wires are on the plug to the idle control valve? I am guess a signal and an earth? If so I might try earthing to the chassis to see if it works on the off chance!? I cannot find a wiring diagram with this in??

Cheers
Lee

Offline mj2326

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Hunting idle with Idle Control Valve on?
« Reply #1 on: October 18, 2010, 06:32:18 PM »
My rx8 was doing this about a month ago my mechanic friend suggested it was to do with the induction kit fitted it was sucking in warm air and the MAF sensor acts as a thermo-probe and doesn\'t like it so causes the revs to go all over the place. I had this kit fitted for about 6 months and never had any problems but only the other month if I drove it hard it managed to stall itself 3 times

I have now fitted the AEM cold induction kit and after a good drive when i stop the vehicle now sits at 800 rev/min happily. Also you could try having the MAF sensor tested
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Offline leeroy_25

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Hunting idle with Idle Control Valve on?
« Reply #2 on: October 18, 2010, 08:17:41 PM »
Hmm?? Interesting but it is perfect with a manually adjusted idle and the valve disconnected so I guess that rules ot the MAF sensor?? I could leave it like it is but I do like to fix tings when possible!!

Cheers
Lee

Offline a.tapos

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Hunting idle with Idle Control Valve on?
« Reply #3 on: November 03, 2010, 04:20:00 PM »
sounds like an air leak into the inlet manifold/piping after throttle body.the o2 sensor sees more air and puts in more fuel which picks revs up then ecu pulls it back down creating a hunt.
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Offline trotter

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Hunting idle with Idle Control Valve on?
« Reply #4 on: November 03, 2010, 04:59:57 PM »
Quote from: a.tapos;724798
sounds like an air leak into the inlet manifold/piping after throttle body.the o2 sensor sees more air and puts in more fuel which picks revs up then ecu pulls it back down creating a hunt.


i had same symptoms with a coincidental problem.

1) Throttle body o-ring had failed so had a bit of a leak
2) Air temp sensor was intermittently failing leading to cyclic hunting mentioned above
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Offline RXSpeedy

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Hunting idle with Idle Control Valve on?
« Reply #5 on: November 03, 2010, 05:02:38 PM »
I had this problem when i fitted my PFC, in the end i removed the pfc from the car until now as im going single. Does your speedo stay on 0mph? as mine jumped the 26kmh even tho the car was stationary lol.

Offline leeroy_25

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Hunting idle with Idle Control Valve on?
« Reply #6 on: November 03, 2010, 07:13:57 PM »
Hi Guys.
Would the problems not mentioned still result even with the idle valve unplugged? I might try and get the inlet pressure checked see if I can detect a leak. I gather with a lot of mods the O2 sensor should really be disabled anyway so if mine is not that could help/cure the problem?

Cheers
Lee

Offline SiH

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Hunting idle with Idle Control Valve on?
« Reply #7 on: November 03, 2010, 07:39:46 PM »
Is it an FD? If so I can 100% confirm it\'s not the MAF!

Mine did similar after I removed the hot start system (not permenantly, I was fault finding) but then sored when I replaced it - very strange.
First suspect on a dodgy idle was always an air leak. Howeve,r I also had issues when one of my turbos was going - oil in the inlet combined with the water injection spray and created an emulsified goop that pooled in the throttle body, blocking up the ICV passage. Cleaned out and all was well again.

Offline leeroy_25

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Hunting idle with Idle Control Valve on?
« Reply #8 on: November 03, 2010, 07:55:38 PM »
Thanks for the info.. The whole thing has had a rebild recently all be apart and cleaned. Single turbo is all healthy as far as I know??
I will first check for a an airleak and see if a gasket is not sealing properly they were new but you never know!

Offline a.tapos

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Hunting idle with Idle Control Valve on?
« Reply #9 on: November 10, 2010, 03:42:27 PM »
i`d say even more likely to be air leak if its had a rebuild as alot of inlet/throttle body gaskets are disturbed but not always replaced the ecu can use fueland ignition to change idle so idle valve is not the only thing that controls it,
ive known primary injector seals to leak air after rebuild,
run the engine at idle then spray brake cleaner around all of throttle body and manifolds and see if revs change.
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Offline BlitzBoy

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Hunting idle with Idle Control Valve on?
« Reply #10 on: November 10, 2010, 03:50:32 PM »
If you cant find an airleak then disable the 02 feedback, most likely the O2 sensor is toast by now and needs replacing, the sensor is over 15 years old in most cases

As been said above with you idle control valve enabled, the 02 sensor sends a reading to the ECU, ECU changes the idle fuel mix, then the ECU tries to control the idle via the valve, if the 02 sensor is kaput you will also get hunting issues
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Offline leeroy_25

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Hunting idle with Idle Control Valve on?
« Reply #11 on: November 10, 2010, 07:45:28 PM »
Thanks guy\'s I will try the old clutch cleaner trick. I forgot about that one! If not I will get a smoke test done on it and make sure O2 is disabled!
Lee