R33 Stalling When Cold + Low Idle Revs

[LexDelta]

Ive been having this problem since I bought my R33, and Id really like to get this sorted out because its very frustrating as you could imagine!

Ive seen a few threads around about this but none have resulted in a solution, just a million suggestions.

Anyway my specific problem is as follows:

When cold the car tends to start roughly, I always push the gas a little for a few seconds because it instantly threatens to stall, but after a few seconds it will settle and I can comfortably get out the car and walk around to let it idle etc to warm up a little. It generally idles in neutral (its manual) at around 1000rpm which is fine. It does seem to fluctuate a bit sometimes though, like it threatens to stall but then the revs randomly come back up again for a while (autochoke?), but its never stalled whilst sitting there.

Once I start driving its a different story, as soon as I get to an intersection/bottom of driveway/traffic lights etc, and put my foot down on the clutch the rpm gets dangerously low, down to around 200rpm before stalling altogether. This seems to be more aggressive when its a cold day, especially in winter, but it still does it even in summer. On cold nights if I dont change gear quick enough when im driving it will stall also (like when changing down to 3rd for a sharp corner, Ill notice the rpm instantly goes dangerously low and will stall if I dont get the revs up quick enough. This is a pain and is also dangerous because no one wants to loose the engine, power assisted breaks and powersteering while driving.....

It usually takes about 15-30mins of driving on a warm day for the engine to stop doing this, which then allows me to pull up at intersections without it stalling (yay no embarrassment!), but still reving very low (now at about 300-400rpm) and this is how the car will be for the rest of the drive. (And it does drive perfectally fine aside from this issue)

Now it is modded in several ways, aftermarket ECU, intercooler, boost timer and so on, so I really have no idea whats causing it. Im going to get rid of the boost timer (illegal in my state anyway) to see if it helps, and some people have said it could be that the air filter needs to be replaced, or the BOV is to blame (which as far as I know is stock), or it could be an issue with the autochoke.

I guess I should start looking into these things, but if anyone has solved this issue Id REALLY love to hear it.

[debmatt09]

Have you cleaned out your AAC, replace fuel filter? I had the exactly same problem the other day, and i changed new fuel filter and cleaned AAC and its running like a dream!

i feel your pain mate.

[Moodles2]

Agree with the above, AAC is most likely, give the AFM a clean with contact cleaner

[LexDelta]

Hmm, haddnt thought of that.

Cheers guys, I'll give it a go and get back to you with the results.

*crosses fingers*

[koduRB25det]

did you fix the problem..? i have the same problem , did every thing no luck [aac clean,maf clean,check engine earth,check and clean air regulater, this and that...]. pls let me know how you go.

[LexDelta]

Hey, still working on the issue, I'll keep posting until I find the solution.

Btw do you have a Microtech ECU? Some people have been saying that could be incorrectly configured.

[koduRB25det]

I have no idea. i'm prity sure i got r33 s2 stock ECU. i will check it and let you know.

[cannabiscorpse]

Just bought my r33, It is standard but was behaving in a very similar way to the ops. I cleaned the aac valve, and it solved it completely.

[Sarumatix]

Mine is behaving the same and usually stalls right when the car is warming up off cold start and onto normal idle.I have already cleaned AFM, cleaned earth, pulled down and cleaned idle control valve, replaced ignator. I will try AAC clean next .

[mad082]

IAC and AAC are all in the one unit as far as i remember (2 pieces in the 1 unit), but it has been a few years since i had my 33. unless you are refering to the cold start valve under the plenum.

[Sarumatix]

Yeah I just went and read the guide and thought.. wait on i've done this DOH. You are correct about the cold start, it's a dog compared to the AAC.

[leer34]

When cold the car tends to start roughly, I always push the gas a little for a few seconds because it instantly threatens to stall, but after a few seconds it will settle and I can comfortably get out the car and walk around to let it idle etc to warm up a little. It generally idles in neutral (its manual) at around 1000rpm which is fine. It does seem to fluctuate a bit sometimes though, like it threatens to stall but then the revs randomly come back up again for a while (autochoke?), but its never stalled whilst sitting there.

Once I start driving its a different story, as soon as I get to an intersection/bottom of driveway/traffic lights etc, and put my foot down on the clutch the rpm gets dangerously low, down to around 200rpm before stalling altogether.

hey mate, i had the same problem with my R34, had to hold the foot on the gas when i started it otherwise it'd stall and at lights, etc. revs would drop and/ or stall. do yourself a favour and check all of your vacuum lines, might only be a very small split in the hose but it will be more than enough to cause you grief if there is one..my problem turned out to be a split in one of the joins in the intercooler piping. i never even thought to check it even though it was right in front of me the whole time. only reason i found it was coz when i tried starting the car again it blew the join completely apart.

i later developed a massive rev hunting problem, that was incredibely embaressing at every set of lights i stopped at. turned out to be a small split in the very thin vac line that runs to the AAC, after a couple of weeks and $2 problem was solved

there are some really good guides on here for cleaning ur AAC and AFM etc...keep trying and you'll find it, nothing will be sweeter than starting your car and being reasonably sure its gona stay started ..good luck

[Nanogrip]

Yeah I agree also with the AAC valve.  I had low idle problems and would get stalls at times.  I even almost crashed one time when the engine suddenly stopped while going a bit fast in the curves.  You can also try cleaning out the mass air flow sensor with a MAF cleaner.  If you did all of them and none worked, try filling up your tank with a gallon of toluene, and drive hard for several minutes and blow out whatever is in the car's system

[LexDelta]

For those still following, Ive found a couple of guides around the place, heres a good one:

http://www.skylinesaustralia.com/forums/topic/345630-r32-gtr-aac-valve-refurbishment/

There was another really good one as well, but so old the pictures were no longer available.

Ill be giving this a go when I can find some spare time (If ever)