R32 Gtr High Idle

[skylimit]

Hi All!

My GTR seems to be idling at 1150rpm, it is a stable idle and it is not idle hunting either. It has always done this since I purchased it. At first I thought it was a specifically tuned that way, but now I wonder?

Has anybody experienced this kind of situation before?

My GTR is pretty much stock with no boost modifications, and only a full Mine's exhaust system from the turbo-back.

I've read many threads on high idling, but none seem to put a finger on the situation.

Can anyone help me fix this problem? Could it be my AAC or something like that?

Any feedback will be much appreciated!

[hanyou]

ive got the same idle. doesnt hunt or anything too. would liek to know the answer as well!

[skylimit]

I've also been looking at some other skyline forums. Other GTR owners seem to speak about the same problem as well.

I've read threads indicative of aac problems, timing problems, afm problems and even wiring problems!

But all of them are just speculative. There were no real solutions.

I've checked my engine bay for cracked or broken off vacumm lines and the such, but I don't want to pull

anything apart until I've found some actual information on what is causing the high but stable idle.

I wonder if it could be the connector on the aac? I heard if you remove it, it could stabilise the idle.

*BTW: for those in the new, AAC stands for auxillary air control valve.

[cowie165]

My idle is the same.

I suspect the car previously ran an aftermarket ECU but was returned to stock on export. Do you guys both have stock ECUs? What I'm getting at is could the switch back to stock reset the idle to a safe default of ~1200rpm and then it should be adjusted using the trim pot on the ECU?

I have just exchanged AFMs for two working units and the consult display indicates they are operating normally.

My AAC valve reads a constant 2%? Is that normal? My TPS is around 0.44V at idle. I'll double check that TPS but pretty sure that's what it read this morning on the way to work.

I'm keen to sort this out too.

[blur]

make sure the carbon canster connections (behind the lhs front headlight) are on properly and the right way around, i had this problem in my gt-r.. try blocking them both off ( from the engine) to see if that lowers the idle.

[jantolis]

*BTW: for those in the new, AAC stands for auxillary air control valve.

Thanks. Was reading all these threads about high idle, even showing pics of what to do and stuff but had no idea what it stands for.

[fuzzy_scuz]

On my 33 I had the same problem until I replaced my timing belt and got a retune with a new set of plugs now I sit on around 800rpm and just under a grand with AC on.

[skylimit]

Hey all,

Sorry for the late reply! Work has been time consuming.

My ECU is stock, but I'll give the methods posted a try. Thanks!

Also, I realised that that my idle is at 1150rpm when the engine is running at optimal temp, from a cold start it idles at about 1000rpm.

I went to Hypertech Motorsports near where I live, and asked them for advice. The guy I spoke to said that you could fix the idle by resetting the idle stepper motor or something. I wonder what he was talking about?

But I'll get it checked out for sure.

Also, I will be resetting my ECU soon: Will give all of you the heads up on what happens.

Cheers all!

[PSI_GTSII]

Mine is the same (32 GTR) nice smooth 1100 rpm idle......

I was told by tuning shop this is a common problem and is an air leak into the inlet manifold caused by old inlet manifold gaskets, it can be fixed by replacing the gasket but is time comsuming and costly...hence I live with the high idle.

BTW, Drops to 950 with AC on.

[PSI_GTSII]

BTW, I have'nt bothered trying yet but you can check for air leaks here by pouring water over the inlet manifold where it seals to the head, if the car hesitates / Splutters then yes there is a leak

[GTRsean]

mine used to idle at 1400 warm so I got the shits with it and adjusted the flat head screw that is in the front of the idle air control valve. Screw it in, out and you will see RPM raise or lower. Now mine is around 950-1000RPM.

[skylimit]

Hey all,

I reset my ECU the other day, a noticeable difference in drivability and power delivery, but no effect on the idle problem.

Went to Dr. Drift today, even he could not diagnose the problem. Had my GTR on diagnostic software, every setting was perfect from AAC response to TPS diagnosis. We experimented by lowering and increasing the AAC controller from the computer, we also switched tps off for troubleshooting purposes. But besides that all settings were nominal/optimal.

Came to a couple of conclusions:

1. Vacuum leak somewhere.

2. Throttle (inner and outer spacing gaskets) on the plenum, are somehow worn or even broken resulting in additional amount of external air being sucked in to the engine, which is not being detected by the AFM.

3. Throttle control arms are not set correctly, or have been deliberately set, to open slightly at idle rpm, but I don't think so: seem to be shutting fully.

4. ECU tuned setting: But Dr. Drift said it should be irrelevant according to software diagnostics.

I am going to check the pressure canisters at the front like 'blur' suggested.

Besides that I am going to take my car to the GTR pro's on tuesday at Hypertech Autosports, I hope GTR builder Eric Schlifelner, may help shed some experience on this problem. Because at the moment I am lost!

If anybody has any info on this, pls share. It will be much appreciated!

Cheers SAU!

[cowie165]

Could you please let me know what your AAC response was like? Mine sits at a continual 2% and the TPS at 0.41V

Were your results similar?

Thanks!

Mark

[skylimit]

Yo Cowie165,

My readings were exactly the same, textbook numbers - and according to Dr Drift that is where they were meant to be.

I also just thought maybe I have a blocked vacuum line somewhere.

Strange hey?

Edited June 4, 2006 by skylimit

[cowie165]

Thanks dude. I was hoping my AAC was incorrect and it'd explain my 1200rpm idle.

Cheers

[skylimit]

Thanks dude. I was hoping my AAC was incorrect and it'd explain my 1200rpm idle.

Cheers

Yeah I'll let everybody know about the idle, when I take it in on Tuesday. I'll be pulling the plenum off and possibly removing the engine in order to cover every angle.

Sigh....got to take it in very early (all day job), should be fun though. Will be checking the ECU mapping very carefully as well, just to make sure it hasn't been re-flashed in japan.

Cheers!

[ADM]

I’ve had a very similar problem with a 1100rpm idle.

This is really starting to annoy me as I recently pulled the complete intake manifold and throttle bodies off to inspect and fix any suspect components, but on reassembly still have the same high idle.

I found the Air Bypass Valve was seized. So I opened it and fixed it where with a 12v input it closed within the factory recommended time. The AAC spring was shagged. I destroyed the plug on the AAC while opening it and had another made. I checked all hoses for cracks and cleaned all components including the throttle bodies. The throttle body gasket did seem to be worn, so I replaced all gaskets. The timing is right, the consult reports that all signals are within factory specs but it still idles at 1100rpm.

This is so frustrating. I’ve also tried three different EPROM’s with no change in idle.

For those of you wanting to test some of the components on the GTR. At the back and underneath the inlet manifold you will see three hoses. The first is the supply to the AAC valve and the second is the supply to the Air Bypass valve. Disconnecting these and plugging them will effectively remove both the AAC and Air Bypass Valves from the idle equation. Blocking the feeds to the CC is also easily done. From there it becomes more difficult as all the hoses that may be causing the leak into the idle control chamber are all hidden under the intake manifold. I’ve had the whole lot apart and still can’t find what’s causing this. I’ve also tried removing the throttle body rose jointed arms so the individual throttles were completely closed, of course with no improvement.

As far as I can see it needs to be a leak in the system somewhere, bypassing air around the throttle bodies, but I certainly can’t find it. Under the intake manifold there are two major feeds that bypass the throttle and are connected to an ‘air bypass chamber’ of sorts. Branching off from this chamber is a myriad of hoses that provide vacuum and idle control functions. Blocking these two major feeds would prove or disprove a vacuum leak, but it involves removing the intake manifold and throttle bodies which is a lot of work to simply test a theory.

At this point I’m going to live with it as I’ve had the car in the shed for too long. I hope someone gives this a go at some point to see what happens.

[SLIPPERY]

geez, i wish i had to put up with an idle of 1100 rpm, that would be lovely

instead, my warm idle is 1800rpm haha..still havnt found the leak yet or faulty AAC valve

plus side is, its quite easy to engage the twin plate because the car will start to drive when i slowly let out the clutch haha

[Beer Baron]

am i the only dude with an R32 GTR that idles at 900rpm flat? and mine even has had the cam timing adjusted so it has a very beaty idle but it still stays on 900rpm.

[SLIPPERY]

im envious richard ! lol