High Idle

[Jap_Muscle]

hey guys,

trying to sort out this issue im having with the idle in my car. just some specs on the motor

r34 gtt

exhaust port+match rb26 head

fully forged rb30 bottom end

gt35 .82

vband straight pipe 3.5" exhaust

1000cc inj

OEM rb26 plenum + tbs

OEM rb26 cams

PFC D jetro ecu

while in motion at any speed if i clutch in the revs go up to ~2000rpm and sit there until the car comes to a stop where it will drop down to around ~1700rpm. sometimes it will bounce around from ~1000rpm to ~2000rpm, somtimes will just sit at 2300rpm.

occasionally when i start the car on a cold day/night it will idle nice at 1000-1200rpm but as soon as the car gets moving and i eventually have to stop and clutch in, the above scenario starts.

im spoken to my tuner and he seems to have tried a few things like playing around with the idle control valve (not sure on specifics) but has had no success. his mentioned something about it being 3L and the amount of air the motor flows is so high, its causing problems.

i see 800hp cars idle nice and fine so why cant i? i dont know much about the tuning side of it and was wondering what can be done about it? i should mention that i had no issues what so ever when i ran a single plazmaman plenum + 80mm tb when i had a rb25 in the car.

any help much appreciated guys! i look like a completely idiot at the lights with such a high idle

[TiTAN]

do you have any vaccume leaks? they can cause a high idle with a MAP ecu. if not have you tried taking the idle control valve off and cleaning the carbon/oil out of it?

does it only idle funny when cold? or it still has a high idle when at operating temp?

[Jap_Muscle]

it idles high all the time.

only sometimes when the motor is cold it idles lower but only sometimes, but as soon as i start driving it starts idling high again.

i highly doubt i have any vacuum leaks because i have no boost issues. ill will confirm with my tuner if he actually cleaned the control idle valve.

[Adriano]

Forget that its an rb30, the air is getting in there somewhere, either the throttles arent adjusted correctly, vacuum leak, or a drama with one of the idle solenoids.

[r33_racer]

lol @ RB30 thing....for starters I would not trust your tuner if his last resort blame was that. As said, engines need excessive air to have high idle.

Did you inspect the new rb26 throttle setup before putting it on the head?

Make sure they were fully opening and closing with no issues and not open too much when closed?

As said you may just need to play with the adjustment. However, usually it is just the idle control valve....

[DVS JEZ]

Did u clean the throttle bodies with carby cleaner? I did this to my 1st rb26 and had similar symptoms. I had to replace the throttle bodies.

Check there is no air leaks at the throttle bodies either. Can also try blocking the idle control valves air pipe. If it idles fine then u need a new idle control valve.

Last but not least disconnect all of the throttle linkages from the main linkage and see if the idle is fixed they might be over adjusted

[Don Dada]

+1 ^^^^

If u cleaned the throttle bodies you can get this

Don't know if the idle control valve these guys are referring to is the aac valve but there is also a air regulator under the plenum close up against the block.....this is used for cold starts.

If it is shagged or unplugged you will get similar symptoms.....to reach it is a real bitch! .....good luck

[NYTSKY]

Make sure you have your aircon turned off.

[ONE R32]

it idles high all the time.

only sometimes when the motor is cold it idles lower but only sometimes, but as soon as i start driving it starts idling high again.

i highly doubt i have any vacuum leaks because i have no boost issues. ill will confirm with my tuner if he actually cleaned the control idle valve.

hi i had that exact same problem on my other car that i sold an i tryed heaps of different things an guy who bought it called me a few days ago to tell me all he did was replace the AFM an now the idle has returned to 100% normal, so diffinatly check that..

[TiTAN]

he is running a map based ECU there is no AFM to play up.

[ONE R32]

he is running a map based ECU there is no AFM to play up.

thats me done then.....

[R31Nismoid]

im spoken to my tuner and he seems to have tried a few things like playing around with the idle control valve (not sure on specifics) but has had no success. his mentioned something about it being 3L and the amount of air the motor flows is so high, its causing problems.

lol what?

Silly tuner you are using mate - go somewhere else if those such comments are being made.

And given you've had power/setup issues for a long time given such comments, perhaps you really do need another workshop/tuner?

As the others have said - it'll be VAC leaks/TB/idle controller. It can't really be anything else

[central coast person]

Im not sure if the ECU you are using has the air regulator operating but i suspect so as it runs in conjunction with the AAC valve. As the thread above states it hard to get too but you will have to visually expect that the shutter is not jamed in a position.

I.E At -20 degrees the valve is fully open

at 20 degrees it is half open and

at 60 degrees it is compleatly closed

I am ony guessing and not sure as MAP sensors are tricky but its worth a shot at checking if the valve is faulty. Another trick is the attach a 12volt DC battery to it

Positive to terminal number one and negative to number 2

Say the surrounding area temp was 20 degrees it would open half way (allow a few mins for it to slowly open) and measure the resistance and is should be near 80

The AAC valve should be checked as well, Somtimes the spring is stuffed or the plunger on the switch so also have a look there. Also check the resistance on the AAC valve which shoul read somewhere near 7.

Keep in mind a vac leak will give faulty readings through these valves so thats another place too look while pulling these bits out. (all hoses around the air control system of the car)

Edited June 7, 2010 by central coast person

[paulr33]

hi

please check the basics

check pipework, solenoids, idle control (basically what the others have said)

post a photo of ETC, SENSOR SW CHECK

post a photo of ETC, FUNCTION SELECT

post a photo of SETTING, REV LIMIT

if you cant work out how to get these, learn here

http://www.paulr33.com/powerfc-emulator/menu.html

[paulr33]

also another note, where and how are the map sensors connected for the djetro kit?

[Kwyjibo]

+1 on the cold start valve, I had the exact problem, sitting at about the exact same revs as you.it pretty much sits in between the plenum/intake manifold and low on the head, on the firewall side of the throttle body(if you are running standard plenum). I think its bolted to the intake manifold by 2 bolts. It t has 2 hoses running too it and a plug connects to the top of it.

The way it is designed is a tiny spring inside it is supposed to hold it shut(or open, I forgot). When voltage is applied the solenoid should open or close it. All you will need to do is open it up, be very careful to not lose any parts, reconnect the spring, then put it back together making sure it has sealed perfectly.

Hopefully that is the issue but based on what the tuner said it could even be a tune issue(however I doubt it would rev that high with just the AAC valve letting air in).

[johnnyt]

i had this issue after cleaning the throttles on my rb26, was extremely frustrating to find out that cleaning the carbon/nissan seal off the throttles resulted in a high idle

[Jap_Muscle]

Update on the situation.

Acid cleaned all throttle bodies, replaced the shaft seals with aftermarket ones from the states.

More info - http://www.xs-engine...idproduct=12106

Replaced the AAC valve (23781-05U11)

picture = http://simex.sakura....es-DSCN7515.jpg

3 coats of tomei throttle coat and no difference what so ever.

hi

please check the basics

check pipework, solenoids, idle control (basically what the others have said)

post a photo of ETC, SENSOR SW CHECK

post a photo of ETC, FUNCTION SELECT

post a photo of SETTING, REV LIMIT

if you cant work out how to get these, learn here

http://www.paulr33.c...lator/menu.html

hey paul,

+1 on the cold start valve, I had the exact problem, sitting at about the exact same revs as you.it pretty much sits in between the plenum/intake manifold and low on the head, on the firewall side of the throttle body(if you are running standard plenum). I think its bolted to the intake manifold by 2 bolts. It t has 2 hoses running too it and a plug connects to the top of it.

The way it is designed is a tiny spring inside it is supposed to hold it shut(or open, I forgot). When voltage is applied the solenoid should open or close it. All you will need to do is open it up, be very careful to not lose any parts, reconnect the spring, then put it back together making sure it has sealed perfectly.

Hopefully that is the issue but based on what the tuner said it could even be a tune issue(however I doubt it would rev that high with just the AAC valve letting air in).

Could you elaborate on exactly what the cold start valve is? Are you referring to the "Idle Control Regulator" part no = 22660-01U10?

this thing here?

Edited September 28, 2011 by Jap_Muscle

[Kenna802]

My guess is Vac leak as well as possible latency timing on the injectors. Mine seemed to run high with that.

[Adriano]

Air is getting in there somehow, 2min and a set of long nose pliars, squeeze the hoses to the plenum. Could be a brake booster, clutch booster, pcv, charcoal canister, or one of the two idle control motors.