R32 GTS-T fluctuating idle

[Blitz_boy]

Hi guys,

a couple of days ago after a hard drive back from the airport my R32 started idling funny. When warm it started bouncing from idle (800 rpm) to 2000 rpm. I've been driving the car for a couple of days now, and it's quite embarassing. When I'm at the lights people think I'm trying to run them!

I have searched the forums long and hard, and have cleaned my AAC Valve to no avail. I now believe it is the air regulator. Problem is I don't know were this is. I read that it was underneath the intake plenum. If someone could take a pic that would be great. Also if anyone knows if this part is servicable, or will I need to replace it?

If anyone esle has had the same problem I would love to hear their input.

[blind_elk]

From your AAC valve, follow the hose back towards the intake pipe. Where it Ts off, follow the hose down into the area under the throttle body and you will find the Air Regulator.

[Blitz_boy]

Thanks, I thought it was that valve. Does anyone know if this part is servicable

or will I need to replace it.

[JAPCAB]

I had this exact same problem! its a pain in the arse but its easily fixed. I replaced my o2 sensor and cleaned AFM with carby cleaner and the problem went away.

[Cubes]

I've had a really bad fluctuating idle that also had a slight miss.

I cleaned the AAC valve and the idle fluctuation was ALMOST gone.

2 years later I put the mesh back on to the AFM and all idle problems are gone.

Its now got a 100% perfect smooth idle.

I have heard of o2 sensors also causing an issue.

My actions would be.

Clean AAC valve

Check if your afm has mesh on both the front and rear. If not slap it on.

If idle problems are still around either get your injectors cleaned/checked out or replace the o2 sensor.

[Blitz_boy]

Thanks guys, I'll try and swap the O2 sensor.

Thats the one on the dump pipe right??

[Rayage]

Hi,

I noticed my idle isn't completely stable either. That last (first) time I took out the AFM for a clean it didn't have a mesh . Will any mesh to or does it have to be a specific (nissan) one?

[Essential]

Where abouts is this AAC Valve located?

Thanks,

Essential.

[Blitz_boy]

OK guys, droped the car off at Nissan today will let you know what the problem is

tomorrow.

[mist]

after a really hard run, e.g. running 70 laps on a circuit over a whole trackday, the hydraulic lifters sometimes get a bit stuffed, which would also cause the funny idle. will usually go back to normal after a few days, or after a service. my own experience..

[Chris32]

after a really hard run, e.g. running 70 laps on a circuit over a whole trackday, the hydraulic lifters sometimes get a bit stuffed, which would also cause the funny idle.  will usually go back to normal after a few days, or after a service.  my own experience..

70 laps would see the complete breakdown of your engine oil, almost to a water like state, hence the problem with the lifters. Do you have a oil cooler? What sort of oil do you run?

In regards to idle problem, AAC valve is usually the culprit

[Blitz_boy]

Ok guys,

Nissan called this mourning and after 2 days of tying to figure it out there still unsure. They said that because it's an import there diagnostic machine can't read

all the codes?! Thay reffered me to another workshop. On top of this they tried to

charge me for there time. I refused to pay as I don't think they did anything.

Hopefully I have better luck with the next place.

[knore]

What is the EXACT product you clean your AFM with?

[mist]

chris32 - heheh i don't run 70 laps all in one go... 10-15 laps at a time, 5-7 sessions a trackday. Using Valvoline fully syn, car has run extremely reliably for over a year of about 15 trackdays inc 2 at Eastern Creek with very low knock readings (std 11 yr old engine with HKS 2530). Running a BEL Garage 19 row oil cooler and 3-core radiator.

[Chris32]

chris32 - heheh i don't run 70 laps all in one go... 10-15 laps at a time, 5-7 sessions a trackday.  Using Valvoline fully syn, car has run extremely reliably for over a year of about 15 trackdays inc 2 at Eastern Creek with very low knock readings (std 11 yr old engine with HKS 2530).  Running a BEL Garage 19 row oil cooler and 3-core radiator.

cool, sounds like a good setup you have there. I run a decent oil cooler myself, and a similar turbo to yours. Only have done one trackday of about 25 laps, but it kept it nice and cool

Chris

[The Alchemist]

why keep on guessing by replacing this and replacing that???? You need to systimatically go through all the vacuum piping to and from the AAC valve & idle control solenoid and clamp them off with a brake line clamp and see if this changes the fast idle. Simple. If the idle does not change then its something else like a inlet manifold gasket blown out (very common in older skylines).

This can be confirmed with the ol can of break disc cleaner in an aerosol can. Give it a squirt alone the inlet manifold right against the cylinder head and if the gasket is gone, broken, blown out, it will get sucked in and the idle will stumble as it burns the break cleaner fluid.

Give that a go.

Changing the O2 sensor just for the sake of it could well be a waste of your money, besides, even if it is stuffed that won't make your idle jump up & down like that.

MIke