Hunting Idle

[esky_mad]

hey guys.

ive got a fair few mods on my car but im still using the stock ecu until i book it in for a remap.

ive only just gotten the car back from having little bits and pieces done and the idle was ok but every now and then you pull up to lights the idle will drop to 1000rpm for a couple of seconds then drop and stall.

i pulled the acc valve off and gave it a good clean. i havent touched the electronic idle on the ecu only the idle screw on the acc valve.

it now idles and doesnt stall once it warms up but it hunts up and down 1000rpm - 2000rpm...1000rpm - 2000rpm etc etc, go for a drive and it still does it. is it basically because of the standard ecu or ive been slack and havent set the idle correctly ?

Mods:

RB20DET

Manual conversion using manual ecu

Garrett GT3040R

Front facing plenum

front mount

exhaust etc etc.

standard airflow meter, injectors, throttle body.

i realise it wont run very well at all with stock ecu but i just wont to get little things like this sorted out before it gets its remap.

real help will be much appreciated.

cheers guys.

Mick.

[Lachlan33]

My knowledge isn't the best but thats a rather large turbo to be using the standard AFM, Injectors and especially ECU. Im going to take a wild stab in the dark and say you should probably look at those supporting mods.

Oh and regards to the pulling upto the lights stalling, you don't have an atmo Blow-off Valve do you?

Edited May 4, 2008 by Lachlan33

[esky_mad]

no BOV. pointless using larger AFM or injectors at this stage. with the stock ecu.

please no more remarks about stock ecu. only sorting out little things before its remapped.

cheers.

Edited May 4, 2008 by esky_mad

[bazr33]

was the little bits that you said, that you got done include the turbo?

My car was hunting like your car at one stage, and found that possible causes were-

Bigger turbo - My Turbo was situated fairly close to the AFM, which the air from the turbo was affecting the AFM. I now have the AFM situated further away, which helped idle.

AAC Valve - I also cleaned mine aswell, like you have done already, but yeah as you noticed hasn't made a difference.

TPS - I have a Throttle body with a VL TPS, which required to be adjusted which fixed the idle and after doing that it doesn't do the hunting anymore.

Also last thing i had a fair few Air leaks which didn't help with Idle, so they are all fixed up and been looked at, and car runs perfect now.

[cmoney]

hey guys.

ive got a fair few mods on my car but im still using the stock ecu until i book it in for a remap.

ive only just gotten the car back from having little bits and pieces done and the idle was ok but every now and then you pull up to lights the idle will drop to 1000rpm for a couple of seconds then drop and stall.

i pulled the acc valve off and gave it a good clean. i havent touched the electronic idle on the ecu only the idle screw on the acc valve.

it now idles and doesnt stall once it warms up but it hunts up and down 1000rpm - 2000rpm...1000rpm - 2000rpm etc etc, go for a drive and it still does it. is it basically because of the standard ecu or ive been slack and havent set the idle correctly ?

Mods:

RB20DET

Manual conversion using manual ecu

Garrett GT3040R

Front facing plenum

front mount

exhaust etc etc.

standard airflow meter, injectors, throttle body.

i realise it wont run very well at all with stock ecu but i just wont to get little things like this sorted out before it gets its remap.

real help will be much appreciated.

cheers guys.

Mick.

Hey Mick.

I have an R32 also with the same problem. I haven't found a solid solution to this yet, but i do have a Microtech computer in mine as a piggy back unit on the standard computer, & as far as i can tell this has nothing to do with the problem.

From what i can gather, i think it could be a vaccun leak problem. I have been advised by a few people of this, but its going for a proper check this weekend in preparation for a full dyno tune. Mine is also running rich, im not sure how yours is doing, but mine is definitely running very rich at idle & low revs. Even high boost seems to be a little rich.

I will advise further once i have a solid diagnosis, & hopefully a solution to the problem. Mine doesnt tend to do it quite so badly with the cold weather atm, but its still all over the place. I will have the turbo & fuel pump & injectors replaced with larger items before the tune anyway in preparation for slightly higher boost, & so i dont blow the standard turbo.

Heres a list of specs in the mean time for comparison:

Microtech LT8 computer

Dual stage boost (12psi & 18psi setting until dyno tune, then hopefully 12psi & 20psi)

Blitz front mount

Standard turbo & fuel system (soon to be replaced with KKR430 turbo)

3" exhaust all the way through

Blitz BOV

Slotted rotors & high performance pads

Urethane suspension rubbers

Lowered

17" Gold 5 Spoke Lenzos

[esky_mad]

cheers for informative replys.

i did the major things like bolting on the turbo, manifold, plenum. i had the lines for the turbo correctly fitting wastegate lines done. heaps of little things. plus things that have nothing to do with the motor.

my airflow meter is quite close to the turbo so thats a good possibility.

cmoney: would apreciate it if you could post up your findings.

cheers guys.

[esky_mad]

update: i dont seem to be able to edit my original post.

the errors codes are reading 43 which is the TPS. would this cause erratic idle and stalling ??

ive got another one here, which im not sure of the condition. no harm in trying it out ??

[bazr33]

the tps should be able to be adjusted.

Mine was able to be adjusted, which helped fixing the idle. (My Tps however is from a vl, and tb is a XF)

Then again yours could just be stuffed.

[esky_mad]

for those people that might be interested, the problems were.

TPS was stuffed, replaced it and it instantly solved the starting issues and holding idle.

pulling up to intersections the car would completely stall, not even a whick of it trying to grab.

i dont run a BOV, and i hunted through heaps of threads and amoungst a bucket load of crap about not running BOV's causing stalling blah blah, i realied it was suffering from compressor surge, made a somewhat dodge inlet pipe to get the afm away from the turbo and BAM, the drama was gone.

simple..........

[cmoney]

Hey Mick.

Got mine sorted. Turned out to be none other than shit connections on the intercooler pipes. They were allowing boost to escape & stuffing the idle. Once i fixed these up, my problem has disappeared, & power has also risen up the top end noticably. No dyno readings, just the feeling when driving it.

Hope this helps ur cause.

For any1 reading, wtb R32 power steering pump. Mine seems to have shit itself....

for those people that might be interested, the problems were.

TPS was stuffed, replaced it and it instantly solved the starting issues and holding idle.

pulling up to intersections the car would completely stall, not even a whick of it trying to grab.

i dont run a BOV, and i hunted through heaps of threads and amoungst a bucket load of crap about not running BOV's causing stalling blah blah, i realied it was suffering from compressor surge, made a somewhat dodge inlet pipe to get the afm away from the turbo and BAM, the drama was gone.

simple..........

[esky_mad]

hey mate,

cheers for that info, my cooler pipes are somewhat suspect but there good for the time being (homemade FTW)

the car has since been tuned, also no dyno tune just a road tune and the car is heaps quicker, bakes 18x10 no probs on .6 bar lol

long life the '20.

[BNR34boy]

should check the intercooler piping and connectors. Sometime the leak it so small that you can't really see it. I usually spray water and add a little bit of soap mixture and see if there are any leaks

[shajar]

Hey Mick.

Got mine sorted. Turned out to be none other than shit connections on the intercooler pipes. They were allowing boost to escape & stuffing the idle. Once i fixed these up, my problem has disappeared, & power has also risen up the top end noticably. No dyno readings, just the feeling when driving it.

Hope this helps ur cause.

For any1 reading, wtb R32 power steering pump. Mine seems to have shit itself....

Hey cmoney, that's damn good news. My shitbox is doing the same thing hunting at idle seems to be more when hot, then if I'm lucky at the lights it stalls...! I've tried f@ckin everything I can think of and had it at the mechanics for over 4hrs, still being no closer to the answer. It only has light mods but the guy I bought it off mentioned the stalling (very intermittent) started when his mechanic put the BOV (now replaced with OEM type) and FMIC on. So I'm thinking of replacing the clamps on the FMIC as they look cheap and don't tighten real tight up without slipping a bit on the thread?

One thing has me perplexed though is to make it idle better I have disconnected the S shaped hose from the Turbo Intake to Rocker cover, it's almost like there's too much vacume and it sending the AFM stupid, hence the hose disconnected seems to mask my problem.

Below is a list among other things that was checked to be Ok on mine so could be good for others with same issue to look at this fault process of elimination.

-Installed CAI partition on Pod filter to stop hot air into AFM

-Replaced coil packs with known good ones

-Replaced Spark plugs

-Replaced Atmo BOV with plumb back OEM

-Cleaned AAC valve

-Check engine oil level

-Check coolant temp sensor for resistance at 80deg. (confirmed with infared temp gun) 324ohms

-Check voltage output from computer to sensor. Ok

-Check MAF for cleanliness- ok

-Check MAF voltage input, 5.2v ok

-Check MAF earth, 30mv-ok

-Check MAF voltage output ign on-.3v eng running- 1.7v ?

-Swap MAF with 2nd known good supplied unit - no obvious change

-Check fuel pressure idle cold-40psi, idle warm-35psi, idle vac hose disconnect-45psi

-Restrict return line and check for change in idle -ng

-Restrict supply line and check for change in idle -better

-Check voltage output from oxygen sensor -slowely max out to 1.2v!!

-Check back of vehicle while O2 sensor reading 1v- black smoke from rear of vehicle

-Replaced Oxygen Sensor - no change

-Disconnect both AAC and FICD valve and check if change in idle- ng

-Check power steering switch for malfunction, disconnect and check for change- no change

*remove PCV hose or oil cap and vehicle idles well.

-Check hose connecting from rocker cover to intake hose - ok

-Check hose connections between MAF and turbo intake - ok

-Checked for air leaks around inlet manifold- ok

-Checked for vac hoses being disconnected - ok

-Blocked all 3 charcoal canister hoses and checked idle - ng

-Checked for fault codes- none found - code 55 - system ok

-Adjusted ignition timming and set SAFC to zero correction and check idle- initally good but did not stabilize always

-Checked voltage to TPS- 5.2v - ok

-Checked voltage output from TPS -varying - ok

-Checked Air Regulator under manifold, measured correct resistance & not blocked

-Adjusted throttle plate stop, tps and iac bypass screw- see how it goes - still being a b1tch......

1 thing I have noticed is it will not boost past 10psi no matter what the Turbosmart bleed valve is set to, could be a good thing seing as I am running the stock Turbo/Injectors, it was happily put out 206RwKW when running but now has been detuned/SAFCII/Timing to for idle issue.

Edited May 29, 2008 by shajar

[cmoney]

Have you checked/replaced the PCV valve &/or hose?? From the list, that seems to be about the only thing i saw missing. Mine only stalled when i turned the aircon on a few times cos it had been sitting for 3 months or so before i bought it. Now she runs fine. I would definitely pull most intercooler hose connections & check them for condition. Then pay close attention when you put them back to ensure they are done well & tight.

My cooler pipes seem to be good quality, however some are a little short &/or at the wrong angle, so i have had to put some clamps right on the end of the silicone joiners to ensure there are no leaks. It was clear before that a few of the joiners were half off the pipes they were supposed to be joining. I made sure i tightened them right up as well, as i am thinking of putting an RB25 in sometime, i will need a new cooler & pipes anyway so im not too worried about overdoing it slightly.

As soon as i had the connections done, she was going fine. I have since wound my BOV back out to dump air & make a fair bit of noise, & there hasnt been a single glitch since. Have you checked ur turbo itself??

From my line of thinking, the engine idling higher would be to build boost in the system. If the turbo has shit itself & isnt building boost, the engine is revving & not getting anywhere. You seem to be making the power, so i wouldnt think so, but just in case.

Hey cmoney, that's damn good news. My shitbox is doing the same thing hunting at idle seems to be more when hot, then if I'm lucky at the lights it stalls...! I've tried f@ckin everything I can think of and had it at the mechanics for over 4hrs, still being no closer to the answer. It only has light mods but the guy I bought it off mentioned the stalling (very intermittent) started when his mechanic put the BOV (now replaced with OEM type) and FMIC on. So I'm thinking of replacing the clamps on the FMIC as they look cheap and don't tighten real tight up without slipping a bit on the thread?

One thing has me perplexed though is to make it idle better I have disconnected the S shaped hose from the Turbo Intake to Rocker cover, it's almost like there's too much vacume and it sending the AFM stupid, hence the hose disconnected seems to mask my problem.

Below is a list among other things that was checked to be Ok on mine so could be good for others with same issue to look at this fault process of elimination.

-Installed CAI partition on Pod filter to stop hot air into AFM

-Replaced coil packs with known good ones

-Replaced Spark plugs

-Replaced Atmo BOV with plumb back OEM

-Cleaned AAC valve

-Check engine oil level

-Check coolant temp sensor for resistance at 80deg. (confirmed with infared temp gun) 324ohms

-Check voltage output from computer to sensor. Ok

-Check MAF for cleanliness- ok

-Check MAF voltage input, 5.2v ok

-Check MAF earth, 30mv-ok

-Check MAF voltage output ign on-.3v eng running- 1.7v ?

-Swap MAF with 2nd known good supplied unit - no obvious change

-Check fuel pressure idle cold-40psi, idle warm-35psi, idle vac hose disconnect-45psi

-Restrict return line and check for change in idle -ng

-Restrict supply line and check for change in idle -better

-Check voltage output from oxygen sensor -slowely max out to 1.2v!!

-Check back of vehicle while O2 sensor reading 1v- black smoke from rear of vehicle

-Replaced Oxygen Sensor - no change

-Disconnect both AAC and FICD valve and check if change in idle- ng

-Check power steering switch for malfunction, disconnect and check for change- no change

*remove PCV hose or oil cap and vehicle idles well.

-Check hose connecting from rocker cover to intake hose - ok

-Check hose connections between MAF and turbo intake - ok

-Checked for air leaks around inlet manifold- ok

-Checked for vac hoses being disconnected - ok

-Blocked all 3 charcoal canister hoses and checked idle - ng

-Checked for fault codes- none found - code 55 - system ok

-Adjusted ignition timming and set SAFC to zero correction and check idle- initally good but did not stabilize always

-Checked voltage to TPS- 5.2v - ok

-Checked voltage output from TPS -varying - ok

-Checked Air Regulator under manifold, measured correct resistance & not blocked

-Adjusted throttle plate stop, tps and iac bypass screw- see how it goes - still being a b1tch......

1 thing I have noticed is it will not boost past 10psi no matter what the Turbosmart bleed valve is set to, could be a good thing seing as I am running the stock Turbo/Injectors, it was happily put out 206RwKW when running but now has been detuned/SAFCII/Timing to for idle issue.

[shajar]

Have you checked/replaced the PCV valve &/or hose?? From the list, that seems to be about the only thing i saw missing. Mine only stalled when i turned the aircon on a few times cos it had been sitting for 3 months or so before i bought it. Now she runs fine. I would definitely pull most intercooler hose connections & check them for condition. Then pay close attention when you put them back to ensure they are done well & tight.

My cooler pipes seem to be good quality, however some are a little short &/or at the wrong angle, so i have had to put some clamps right on the end of the silicone joiners to ensure there are no leaks. It was clear before that a few of the joiners were half off the pipes they were supposed to be joining. I made sure i tightened them right up as well, as i am thinking of putting an RB25 in sometime, i will need a new cooler & pipes anyway so im not too worried about overdoing it slightly.

As soon as i had the connections done, she was going fine. I have since wound my BOV back out to dump air & make a fair bit of noise, & there hasnt been a single glitch since. Have you checked ur turbo itself??

From my line of thinking, the engine idling higher would be to build boost in the system. If the turbo has shit itself & isnt building boost, the engine is revving & not getting anywhere. You seem to be making the power, so i wouldnt think so, but just in case.

Yes checked it, it's working ok, the reason it comes good when removed is it's doing the same thing as the Intake pipe to rocker cover on other side when removed (allows more air in), seems like too much vacume????

Yes my IC piping is same as yours it does not quite line up correctly (little short &/or at the wrong angle) though the clamps look a little weak, although I did squirt Start-Ya-Bastard on them to see if Idle would rise from sucking it in, did nothing so seal might be ok, clapms are cheap enough to replace and 1 less thing to think of.

[cmoney]

Yeah, thats a good place to try just in case. Mine looked fine from the top, but i found my leak was out the bottom where i couldn't actually see, nor could i feel the leak. I just made sure the clamps were definitely over the ends of all the hoses & sealing properly. Even on 18psi there's no leaks or dramas that i can find.

I have a question though. Where is the PCV valve....?? Ive looked but cant find it.

Yes checked it, it's working ok, the reason it comes good when removed is it's doing the same thing as the Intake pipe to rocker cover on other side when removed (allows more air in), seems like too much vacume????

Yes my IC piping is same as yours it does not quite line up correctly (little short &/or at the wrong angle) though the clamps look a little weak, although I did squirt Start-Ya-Bastard on them to see if Idle would rise from sucking it in, did nothing so seal might be ok, clapms are cheap enough to replace and 1 less thing to think of.

[smidy]

i don't know much as you guys about all these diagnosticts, but from my experience i had with rpm being unstable and "jumpy" and also rich fuel consumption- i found i had several very small cracks in the cooling bars of my standard intercooler where they join against the side chambers, this obviously had air leaks in the flow of things. it caused idle variation from 800rpm - 1400rpm roughly, choking,spluttering when higher acceleration was giving and also stupid fuel consumption. i don't have any where near the amount of mods as everyone but figure may help with similar problems everyone has had.

i purchased off ebay another standard intercooler ( no cracks in this one and only $21.65 inc. postage ), fiitted it and presto no more shitfull skyline. rpm is shitloads more consistent, no lag or splutter in higher acceleration and fuel consumption has improved, and yes no bov!! am going to purchase apexi power fc as i can afford it so when more mods are added i can tune accordingly. hope this may shed some light or brighten it for others.

[nizmonut]

10psi max? that cause your rec bov, may have 10 pound spring in it, and same goes for wastegate actuator.

[cmoney]

*Update on mine*

I thought i had the problem fixed, but good old Murphy popped his head up.

Whatever i do seems to fix the problem for a few days, then she stuffs up again.

So far, intercooler pipe leaks have been fixed. Power is definitely better, but still playing up. Cleaned & replaced AAC valve, made it better, but still doing it. Cleaned AFM, worked for a day or 2 each time, then back to it again. Changed plugs to NGK iridium, no real difference. Runs cleaner, but no idle difference. Cleaned throttle body of gunk & some intercooler pipes, still the same.

Today i will be pulling the battery & allowing the car to sit, before replacing it with a good 1. Hopefully to reset the ECU, & see if this helps at all. Soon, once stock arrives, i'll also be replacing the AFM to see if its faulty. The problem i may be having is, the Mircotech i have is a piggyback. As far as i've been informed by the tuning shop, it controls Ignition & Fuel. The standard ECU still has control of idle, with all air sensors connected to it. If the problem is still there once the AFM is replaced, im going to rip the Microtech out & fit a new board to the standard ECU to allow that to be tuned. See if i can isolate the problem if its still there.

The main thing, the car runs well up to operating temp, & even for a while after. Its usually after 30 mins of driving or so, it starts to stuff up. That makes me lean towards the AFM or computer, but time will tell. I'll keep you posted, in the mean time, good luck getting yours sorted.

hey guys.

ive got a fair few mods on my car but im still using the stock ecu until i book it in for a remap.

ive only just gotten the car back from having little bits and pieces done and the idle was ok but every now and then you pull up to lights the idle will drop to 1000rpm for a couple of seconds then drop and stall.

i pulled the acc valve off and gave it a good clean. i havent touched the electronic idle on the ecu only the idle screw on the acc valve.

it now idles and doesnt stall once it warms up but it hunts up and down 1000rpm - 2000rpm...1000rpm - 2000rpm etc etc, go for a drive and it still does it. is it basically because of the standard ecu or ive been slack and havent set the idle correctly ?

Mods:

RB20DET

Manual conversion using manual ecu

Garrett GT3040R

Front facing plenum

front mount

exhaust etc etc.

standard airflow meter, injectors, throttle body.

i realise it wont run very well at all with stock ecu but i just wont to get little things like this sorted out before it gets its remap.

real help will be much appreciated.

cheers guys.

Mick.