Rough Idle And Turbo Cutting Out

[bteng]

I have a r33 gts-t s2 which in the last 2 weeks has been having some weird idle problems. I also had problems with the turbo cutting out at around 3500 revs. Took it to the garage but at this point the idle wasn't happening (had stopped doing it the day before despite it doing it for the past 2 weeks every day). They changed the vacuum lines on it and turned down the boost and they checked it with another afm.

It seemed fine after this however last night it started doing it again. The turbo seemed to cut out and after this the rough idle started again. When the i stopped at the lights it was idling at between just above 0 - 500 rpm. If I then put my foot down it goes then suddenly the car will go completely quiet like it has died however the revs will stay completely still (at this point it was at about 2500 rpm) then i release the pedal and it fires back up. Any suggestions as to what this could be?

[laggn til 3500?..worth it]

hey mate had similar prob on my s2...went to the tuner and ended up being my o2 sensor as well as a faulty afm....are you running power fc?

[bteng]

hey mate had similar prob on my s2...went to the tuner and ended up being my o2 sensor as well as a faulty afm....are you running power fc?

thanks for the reply, running stock ecu with aftermarket intercooler, bov, pod and boost controller

im going to take it back and get him to check the o2 sensor and anything else he think it might be

[SargeRX8]

The turbo wont 'cut out' so to speak. Do you hear the turbo stop spooling or do you just feel a lack of power? Could be many many things. O2 sensor is good for a change, its probably never been changed before. If you rev it past 3500 without boosting(light throttle all the way), does it still limp? Get a compression test done or a leak down test done. Car seems too stock to be suffering like this. Spark plugs, coil packs, O2 sensor, fuel pump etc. There are alot of things to check out. Chuck a consult cable onto it see if it reads anything(although I think the check engine will light up, but don't hold me on that).

[DVS JEZ]

If its not te afm. Connect a fuel flow and prrssure tester. Ur fuel pump might be dead

[StealthX]

Aftermarket BOV?

There's your problem.

[SargeRX8]

Aftermarket BOV?

There's your problem.

I've had an aftermarket atmo bov on stock ecu and rb25det r33 and it ran fine as stock. Even blocked it for flutter awesomeness didn't cause it to stall or idle rough idle.

[bteng]

The turbo wont 'cut out' so to speak. Do you hear the turbo stop spooling or do you just feel a lack of power? Could be many many things. O2 sensor is good for a change, its probably never been changed before. If you rev it past 3500 without boosting(light throttle all the way), does it still limp? Get a compression test done or a leak down test done. Car seems too stock to be suffering like this. Spark plugs, coil packs, O2 sensor, fuel pump etc. There are alot of things to check out. Chuck a consult cable onto it see if it reads anything(although I think the check engine will light up, but don't hold me on that).

Basically once it "cuts outs" the whole car jolts and i lose power. This only happens when boosting not when just accelerating lightly.

And this is video of the strange idle, it doesn't just sit at low rpms but wavers up and down... was happening this morning.

[simpletool]

Almost certainly an intake piping air leak. In order of likelihood:

1. BOV

2. BOV

3. hose clamps /joins (but do not over-tighten and break them!)

4. small hose leak

5. plenum leak

6. intercooler leak

7. maybe an AFM problem (wiring or plug since you have changed the AFM).

Edited April 21, 2011 by simpletool

[simpletool]

FWIW

I've had an aftermarket atmo bov on stock ecu and rb25det r33 and it ran fine as stock. Even blocked it for flutter awesomeness didn't cause it to stall or idle rough idle.

Yes, but that doesn't mean this isn't a problem for this engine. Aftermarket BOVs, especially atmo are just asking for trouble. (btw. blocking the atmo BOV means it is no longer an ATMO BOV and will actually CURE stalling and rough idle issues)

[luvpsi]

i reckon this problem could be a AFM issue if it was a intake leak wouldnt it not run at all

[PM-R33]

Lol at suggesting the 02 sensor. Seems some people have no idea what an 02 sensor does.

Is there any smoke coming out of the car's exhaust on idle?

It really does sound like a faulty AFM.

[laggn til 3500?..worth it]

Lol at suggesting the 02 sensor. Seems some people have no idea what an 02 sensor does.

Is there any smoke coming out of the car's exhaust on idle?

It really does sound like a faulty AFM.

y u got 2 be such a hero man if you actually read my post i said i had a similar problem i didn't say THE SAME. LOL at urself fooooollll

[laggn til 3500?..worth it]

thanks for the reply, running stock ecu with aftermarket intercooler, bov, pod and boost controller

im going to take it back and get him to check the o2 sensor and anything else he think it might be

yeh man best way is to get the pros to check it out...i learnt the hard way wen i took some wrong advice from a internet mechanic $$$$$$$$$wasted$$$$$$$ even tho sum people kno there shit down pat there always a chance of failure ...its worth paying extra for peace of mind..

well let us kno how ya go

[PM-R33]

y u got 2 be such a hero man if you actually read my post i said i had a similar problem i didn't say THE SAME. LOL at urself fooooollll

Good one. Why even mention it then? It just confuses him into thinking it could be a cause. It's like me saying "Yeah man, I had a similar problem and had to get my turbo and afm replaced". Suddenly he will freak out into thinking he needs a new turbo. Comprende ese?

yeh man best way is to get the pros to check it out...i learnt the hard way wen i took some wrong advice from a internet mechanic $$$$$$$$$wasted$$$$$$$ even tho sum people kno there shit down pat there always a chance of failure ...its worth paying extra for peace of mind..

well let us kno how ya go

"The pro's". Spoken like some one that has no clue about cars. This type of attitude on here will not get you far.

[bteng]

OK, so the guy who tunes my brothers car had to drop something off here so he took a quick look at it while it was doing the weird idle and he reckons its the bov. Going to try a stock bov on it tomorrow and see if that fixes the issue.

[PM-R33]

Hence why I asked about the smoke out of the exhaust. If you have an intake leak as bad as what your car appears to have it will be overfueling a lot and you will usually have black smoke coming out of the exhaust. That BOV would have to be leaking hardcore to cause an idle to be that bad ie. be literally completely open.

[laggn til 3500?..worth it]

Good one. Why even mention it then? It just confuses him into thinking it could be a cause. It's like me saying "Yeah man, I had a similar problem and had to get my turbo and afm replaced". Suddenly he will freak out into thinking he needs a new turbo. Comprende ese?

"The pro's". Spoken like some one that has no clue about cars. This type of attitude on here will not get you far.

obviously you dont know much better than me if your post sounds just like mine...wen u mention AFM problem??!....you need to relax !! if you kno more than a professional import mechanic i apologise.. if you dont maybe you should get off ur hi- horse and chill. Dude y would he freak out geezzzz ... I just wanted to suggest he get his tuner to check it out first rather than him spending $ on uneeded shit...and then then you start having a cry ...

you say "This type of attitude on here will not get you far" ....ahahhaahahhahahahahhahaaha thats priceless dunno wat in helll u mean by this but maybe your just having a BAD DAY..i think you have the attitude issue mate i love my skyline and respect all nissan fans ... thats my attitude!!!!

BOOOOOMMMM!!! ......n yehh its like that!!! maybe this will cheer you up a bit aahaha

[Rolls]

Sounds like it could be fuel pump to me, often they will cut in and out when they are dying hence fuel starvation where you won't stall but you'll get a massive lean condition and it won't rev.

It could however be one of many many things, I would recommend taking it to a workshop and letting them sort it, without the proper equipment it could be quite hard to diagnose. If you don't want to though I'd get a consult and check for error codes to rule out sensors, then chuck it on a dyno to see if its leaning out due to a fueling issue.

[JKR-32]

upon my first read I would have assumed AFM or fuel pump. The idle issue does sound more like a leak in a vacuum line or intake (BOV) though. Most likely not an O2 sensor though, as they only lean out fuel mixtures when cruising.....

I was having some dodgy shit going on with my car cutting in and out at rpm and load, and it was the AFM, it wasn't hunting around on idle like that though, thus why a vacuum leak would make sense .

Edited April 21, 2011 by JKR-32