High Idle

[GTRPSI]

The idle control valve also has a gasket on it from memory, take the whole valve off and check its not full of crap. Also disconnect (unplug) it and start the engine to control the base idle yourself via the screw, that way you control its position, regardless of what the ECU wants to do.

Warm up valve, just get a pair of multi grip pliers and clamp one of the hoses shut to close it, however you said you changed it anyway.

Spray some WD40 around your manifold joins and listen to the idle to see if you have a vacuum leak.

Check hoses under the manifold (and elsewhere) for cracks, easy to overlook a perished hose.

[Jap_Muscle]

unplug the IAC if it doesnt drop then pull it off and undo the 4 screws - i had hunting and high idle issues for a very long time and finally decided to pull the thing apart

turns out the tensioner spring inside the valve had broken, replaced it and perfect idle first start.

I had sourced a second hand AAC (Auxiliry Air Control - 23781-05U11, i hope this is what your talkn about pic http://simex.sakura.ne.jp/blog/hermes-DSCN7515.jpg)

and there was no change what so ever. Will check it again when i pull it aprt. How exactly do you check the tensioner spring?

The idle control valve also has a gasket on it from memory, take the whole valve off and check its not full of crap. Also disconnect (unplug) it and start the engine to control the base idle yourself via the screw, that way you control its position, regardless of what the ECU wants to do.

Warm up valve, just get a pair of multi grip pliers and clamp one of the hoses shut to close it, however you said you changed it anyway.

Spray some WD40 around your manifold joins and listen to the idle to see if you have a vacuum leak.

Check hoses under the manifold (and elsewhere) for cracks, easy to overlook a perished hose.

Replaced the gasket with a new nissan one

http://www.kudosmotorsports.com/catalog/nissan-gasket-aac-valve-genuine-nissan-skyling-r32-gts-gtst-gts4-gts25-rb20de-rb20det-rb25de-p-1090.html

Ill make sure to unplug the AAC and see what it does the next time i open it up.

Also ordered a new TPS and Cols start Valve.

[Sarumatix]

i've had similar'ish' issues with my 26 idling a little up and down for sometime, played with all of the aforementioned and didn't see any improvement. stock AFM setup though but I felt there was something I must be missing .

[Jap_Muscle]

Great news guys!!

Originally had the starter motor replaced as the car has been struggling to start over the past month. Suspected bad earth could have caused the high idle. Had it replaced but did not fix the issue. We then replaced the TPS due to a weird a voltage range from 0.39v - 2.56v. After resetting this and replacing the actual TPS unit, we were hopeful but still no change.

Finally after replacing the Idle Control Regulator (had to rip the plenum off to do this) the cars idling at a smooth 950rpm.

After close to a year of sounding like i was launching off the line at every intersection, i am pleased to say the problem has been solved.

Thank you to everyone help!!!

p.s - if anyone is having problems with idle please shoot me a PM, ill try to be as helpful as i can.

[rondofj]

Hi im just wondering if i can use WD-40 to clean my iac, I have gone through a tute from another link on how to dismantle n clean it. Anyone used WD-40? Thats what i currently have and cant be stuffed running off to get carby cleaner

[scotty nm35]

WD40 is a great degreaser, should work well although it can attack some rubbers.

[rondofj]

Cheers scott

[Jap_Muscle]

Hi Guys,

Well after a few weeks it seems the idle has again started to become unstable. A few new symtoms which ill document for you now.

I am able to se the idle as low or as high as i want with via the adjustable screw on the IAV. I was never able to do this previously as it would always idle above ~1500rpm regardless of the screw. This was fixed after replacing the Idle Control Regulator (Cold start Valve). While i had the plenum off i also had my starter motor reconditioned, as the car struggled to start when the car warmed up.

Now a month down the track, it seems the problem is back, however slightly different. The car will idle fine but as soon as i turn the AC on the idle begins to hunt, and sometimes just drop and stall. If it does stall i cant fire it back up. It seems the starter motor begins to fail. It clicks but never fires. I sometimes have to leave it for 15min and then it will start fine. So strange!

Ive also noticed that my Boost controller (Apexi AVCR) registers throttle on random occasions. I suspect this might be why it hunts? However I check my Power FC throttle voltage and it sits at around 0.5v-0.53v on idle,which is fine right? But only ~2.63v on WOT. Is this correct?

Another strange thing ive noticed is that the ill set the idle on a really hot day, then on a cool day it hunts around. But if i set it on a cool day it idles really high when the day gets hot. is there no way to control this regardless of how hot it is?

i miss the rumble of a rb @ 900rpm =[

Edited January 24, 2012 by Jap_Muscle

[rondofj]

Hi Guys,

Well after a few weeks it seems the idle has again started to become unstable. A few new symtoms which ill document for you now.

I am able to se the idle as low or as high as i want with via the adjustable screw on the IAV. I was never able to do this previously as it would always idle above ~1500rpm regardless of the screw. This was fixed after replacing the Idle Control Regulator (Cold start Valve). While i had the plenum off i also had my starter motor reconditioned, as the car struggled to start when the car warmed up.

Now a month down the track, it seems the problem is back, however slightly different. The car will idle fine but as soon as i turn the AC on the idle begins to hunt, and sometimes just drop and stall. If it does stall i cant fire it back up. It seems the starter motor begins to fail. It clicks but never fires. I sometimes have to leave it for 15min and then it will start fine. So strange!

Ive also noticed that my Boost controller (Apexi AVCR) registers throttle on random occasions. I suspect this might be why it hunts? However I check my Power FC throttle voltage and it sits at around 0.5v-0.53v on idle,which is fine right? But only ~2.63v on WOT. Is this correct?

Another strange thing ive noticed is that the ill set the idle on a really hot day, then on a cool day it hunts around. But if i set it on a cool day it idles really high when the day gets hot. is there no way to control this regardless of how hot it is?

i miss the rumble of a rb @ 900rpm =[

My idle is unnecessarily high on cold starts, even now in summer, like around 1400rpms, but once warm, it drops to 850-900rpms. When I disconnect the plug from the IACV at the back of the intake manifold during cold starts, the idle immediately drops to the normal 850-900rpms. I have already cleaned my IACV, just wondering if my cold start valve is farked.. On my NEO, the IACV and cold start valve is one unit unlike R33s.

[SargeRX8]

I think my cold start valve might be f**ked but hell there is no way I am taking off the plenum to fix it.

You've got a power FC JAP MUSCLE. I think that maybe your car has learnt to work with a faulty cold start valve. If you are able to, you should backup your tune then reset your ECU and let it self learn the idle again. My car would go insane with the AC on, works perfectly now. I remember when I got it back from its first tune, it was idling at 1800rpm with the AC on.

[rondofj]

I think my cold start valve might be f**ked but hell there is no way I am taking off the plenum to fix it.

You've got a power FC JAP MUSCLE. I think that maybe your car has learnt to work with a faulty cold start valve. If you are able to, you should backup your tune then reset your ECU and let it self learn the idle again. My car would go insane with the AC on, works perfectly now. I remember when I got it back from its first tune, it was idling at 1800rpm with the AC on.

just disconnect your plug while its idling high and see if it drops back down to normal speeds.

[Jap_Muscle]

I think my cold start valve might be f**ked but hell there is no way I am taking off the plenum to fix it.

You've got a power FC JAP MUSCLE. I think that maybe your car has learnt to work with a faulty cold start valve. If you are able to, you should backup your tune then reset your ECU and let it self learn the idle again. My car would go insane with the AC on, works perfectly now. I remember when I got it back from its first tune, it was idling at 1800rpm with the AC on.

interesting....ill give that a go, thanks!

[DVS JEZ]

Jap try setting the tps to .44V ish TPS closed. I know with nissan ecu .5V is borderline of not running in the idle maps.

With WOT u should be seeing near 4V. Check the throttke is opening 100%. If it is try another tps

[Jap_Muscle]

Jap try setting the tps to .44V ish TPS closed. I know with nissan ecu .5V is borderline of not running in the idle maps.

With WOT u should be seeing near 4V. Check the throttke is opening 100%. If it is try another tps

Now that you mention it, In the PFC functions check screen, the IDL circle never lights up. Almost as if the car is never in a idle state. How does one know exactly what voltage it should be?

will give .44v a go though. cheers

edit::

How does one exactly set the voltage? i usually had my mechanic do it.

Edited January 24, 2012 by Jap_Muscle

[wolverine]

Read commander and adjust the TPS voltage until you have the correct value. Anywhere between 0.25v to .45v should be fine as far as I know.

[Jap_Muscle]

Read commander and adjust the TPS voltage until you have the correct value. Anywhere between 0.25v to .45v should be fine as far as I know.

Are tou saying i can use te commander to adjust the tps voltge? On what screen is that done?!?

[SargeRX8]

I'm reading that you have to manually adjust the TPS(turning it) to adjust the voltage, which you read on the PFC commander. I was also reading, specific to Nistune(but I'm sure PFC is the same), that when you look at the sensor page on the hand controller, the TPS circle should be solid until the lightest of lightest throttle touches which will bring it out of idle. If it need more than the lightest of lightest of touches then you adjust the TPS to the right voltage until you have it switch off idle as soon as you touch the throttle.

[STATUS]

I'm reading that you have to manually adjust the TPS(turning it) to adjust the voltage, which you read on the PFC commander. I was also reading, specific to Nistune(but I'm sure PFC is the same), that when you look at the sensor page on the hand controller, the TPS circle should be solid until the lightest of lightest throttle touches which will bring it out of idle. If it need more than the lightest of lightest of touches then you adjust the TPS to the right voltage until you have it switch off idle as soon as you touch the throttle.

correct slide the tps to adjust the tps voltage.

Andrew fitting up some 02 sensors to your car will help ten fold too especially your cruise trims.

Once you set your tps drop past one sat and i will check the idle lambda for you, your 26 had a vac leak through the old idle control valve (going on your above statements) so your idle mixtures will be way off now its fixed.

not gonna cost you a cent.

[Jap_Muscle]

I'm reading that you have to manually adjust the TPS(turning it) to adjust the voltage, which you read on the PFC commander. I was also reading, specific to Nistune(but I'm sure PFC is the same), that when you look at the sensor page on the hand controller, the TPS circle should be solid until the lightest of lightest throttle touches which will bring it out of idle. If it need more than the lightest of lightest of touches then you adjust the TPS to the right voltage until you have it switch off idle as soon as you touch the throttle.

I cant seem to find a screw or "sliding adjustment" on the tps. When you say i should be "turning" it, do you mean the whole unit?

Andrew fitting up some 02 sensors to your car will help ten fold too especially your cruise trims.

Once you set your tps drop past one sat and i will check the idle lambda for you, your 26 had a vac leak through the old idle control valve (going on your above statements) so your idle mixtures will be way off now its fixed.

not gonna cost you a cent.

Yeh ive been meaning to get onto the 02 sensor for a while but unlike the idle which shits me everyday i drive it, it hasnt been on the top of my list to fix. But dont worry it will be done! Ill make sure to drop by sometime when i get all this sorted, Thanks!

Edited January 25, 2012 by Jap_Muscle

[Jap_Muscle]

Ok i manage to figure it out although it didnt really help. I got a bit desperate and ended up re-initialising the pfc and it seems to be under control to a certain degree. Hunts still around 860-920rpm. Sounds lumpy so its not all bad.

Tps on idle is around 0.39-0.40v on idle but how are u suppose to increase the WOT voltage?

from paulr33s PFC guide im suppose to let it idle for up to 30min to let it relearn while turning AC on and off.

Bit devo'ed about losing my tune though =[