Please Help!

[=STEVE=]

Hi everyone,

Background:

The car is an R32 skyline with 139,000 kms on the clock. It has been well maintained engine looks tidy and has full log book history. The car is pretty much stock, the only mod is a full 3 inch zorst inc metal cat and 3inch dump off the stock turbo. So stock air box and stock intercooler all in wonderful condition.

Problem:

Very randomly the car will do the following;

- While driving, whether under boost or just driving steady, the engine will cut out and cut back in again.

- When stopped engine will run lumpy and stall and starts fine afterwards. (this happens occasionly, not as much as the above)

- Heavy engine vibrations when in higher rev range.

Steps taken to try and fix:

- changed fuel filter

- cleaned air filter

- checked spark plugs (iridiums in excellent condition)

- checked fuel pump filter (in tank)... little bit of crap in there. Cleaned with kero, dried and reinserted into tank.

- did a basic test on coil packs 1,2 and 5 (easiest to test without removal). I wasnt to sure on the resistance levels but the three were consistant with eachother.

- inspected afm... looks tidy. (did this because was a bit worried about k&n panel filter being over oiled from previous owner)

Nothing has changed a single thing into the way it is running. Can someone please help me diagnose the problem, its ripping my brain appart arg!

Cheers, steve

Edited May 12, 2010 by =STEVE=

[mosquitocoils]

?

[PUDZ 32R]

i think we need a little bit more info here..

are your iridiums gapped to .8? or higher?

can you tell the difference between a missfire and a rough idle? if it is a missfire it will most probably be a coil pack. could be a plug too. just because the plug looks good doesnt mean it is good.

will the engine rev over 2300RPM when it is playing up? if not it is most likely your AFM.

could also be a boost or vac leak but it seems unlikely considering you say the problem is intermittent. a vac leak will cause a rough idle and possibly stalling depending how bad it is.

any more accurate info will help us diagnose your problems

[=STEVE=]

i think we need a little bit more info here..

are your iridiums gapped to .8? or higher?

can you tell the difference between a missfire and a rough idle? if it is a missfire it will most probably be a coil pack. could be a plug too. just because the plug looks good doesnt mean it is good.

will the engine rev over 2300RPM when it is playing up? if not it is most likely your AFM.

could also be a boost or vac leak but it seems unlikely considering you say the problem is intermittent. a vac leak will cause a rough idle and possibly stalling depending how bad it is.

any more accurate info will help us diagnose your problems

well the plugs are gapped right, checked the part number with repco all good there.

sometimes it will idle fine but other times the idle is irratic... say 600 rpm to 1200rpm etc.

The engine revs fine. Just tonight when i was driving it cut out in the middle of the street so when i eventually got it restarted i dropped the shit out of it and it lit up the tyres fine. Then i few seconds after normal driving it cut in and out again.

The intercooler piping is stock and havent touch it so i think its unlikely to be that. Also it would not account for the total randomness of it all.

When i do get in a chance to up it my aftermarket (autometer gauge) reads normal and holds at 12psi.

Also the engine does clunk out when its cold so i dont think that its the coil packs because i have herd they usually only tend to bugger up when hot.

cheers

[Yts]

well the plugs are gapped right, checked the part number with repco all good there.

sometimes it will idle fine but other times the idle is irratic... say 600 rpm to 1200rpm etc.

The engine revs fine. Just tonight when i was driving it cut out in the middle of the street so when i eventually got it restarted i dropped the shit out of it and it lit up the tyres fine. Then i few seconds after normal driving it cut in and out again.

The intercooler piping is stock and havent touch it so i think its unlikely to be that. Also it would not account for the total randomness of it all.

When i do get in a chance to up it my aftermarket (autometer gauge) reads normal and holds at 12psi.

Also the engine does clunk out when its cold so i dont think that its the coil packs because i have herd they usually only tend to bugger up when hot.

cheers

the idle could be something to do with your i think its called the IAC motor i think thats what its called, solinoid up the back near your plenum could be dirty or have crap in it that affects the airflow, or the other thing to check would be your stock BOV could have a leak, when i installed an atmo bov on my old r32 i used to get a similar problem exactly like yours cause it didnt like the venting to atmo and rb20's are know for it.

[=STEVE=]

the idle could be something to do with your i think its called the IAC motor i think thats what its called, solinoid up the back near your plenum could be dirty or have crap in it that affects the airflow, or the other thing to check would be your stock BOV could have a leak, when i installed an atmo bov on my old r32 i used to get a similar problem exactly like yours cause it didnt like the venting to atmo and rb20's are know for it.

Yea i've heard of the bov causing trouble if vented to atmo. But it looks quite tidy as said its only done 139,000ks. But i will look into that.

IAC sounds like a good candidate because it effects the engine depending on the amount of load? Is that right? But anyways il look into that, cheers!

Keep the suggestions coming guys, can use as many as possible. Its so fkn wierd! I've never seen this sort of thing happen before. lol

[=STEVE=]

Just an update:

I was driving this morning for about 10 minutes and the car ran fine???? WTF ????

So it may have something to do with the tempurature because it was under 10 degrees here this morning.

Keep the idea's coming guys!

cheers, steve

[mosquitocoils]

Does it die while driving (actually cruising at say 2000rpm) or when you are coming to a stop?

If it's the latter I would be looking at your AAC/IAC valve, rip it off and give her a clean out with carby cleaner. Quite easy to do.

If it's while you're driving and putting some power into it I would suggest it would be spark related so coilpacks, plugs blah blah blah.

The vibration at high RPM is an interesting one though. Could it be timing related?

[=STEVE=]

Hi everyone,

Just another update;

Checked the IAC... It looks fine, rather tidy.

Checked the contact point on coil pack #1... that looks imac aswell.

steve

[PUDZ 32R]

i would say now from the extra info that you could have a dry joint in the AFM. mine did some of that drive fine then cut out for no good reason crap and it ended up being the AFM pins inside the unit had dry joins. i just reflowed the solder and now it hasnt missed a beat.

try swappng AFMs with a mate if possible.

[Malteaz]

Yeah have/had the same problem in my 32.

Would cut out whether in boost or not.

I replaced the AFM instead of cleaning it as they arn't that expensive & fixed the cut in & out.

In regards to your lumpy is it when your coming to stop or say when your sitting at the lights.

I've heard dirty AAC, leaking bov or VAC leak..

[gelousi]

My r32 used to have the same problem, lumpy idle and when i would give it to it would splatter only when it was warm. turned out one of the knock sensors was not plugged in theres two one near cyl 5 and other near cyl2 just under the intake manifold make sure there in or put ur ecu into diagnostic and check for error codes

[=STEVE=]

hey everyone,

I fixed it! thank gawd!

It ended up being the afm... The K&N pannel air filter must have been over oiled (previous owner) and it irritated the afm. So i bought some specifically made afm cleaner and pissed the filter and air box off and replaced it with hks ram intake (mushroom type)

It now runs primeo! sounds way cooler too. Heaps of suction!

Thanks for everyone that contributed, really appreciate the help.

cheers,

steve