R33 Gtst Hunting

[Exodus01]

Hi all,

Just bought my brothers r33 gtst which is hunting whilst driving or idle..

It was blowing some black smoke which has stopped since replacing the fuel filter, spark plugs and oil filter/oil.

At the same time the hunting stopped so i thought i had fixed it however today it started again....

I am sus to it being the coil packs ?? (does this sound like a possibility?)

didnt want to pointlessly buy some so was wondering if anyone in Penrith/western sydney has any i could try and see if they fixed the problem?

[niZmO_Man]

Tried cleaning the Idle or Auxiliary air valve on the intake plenum?

[Exodus01]

sorry how do i do that? i did a quick search and couldnt find a good picture or description

[SargeRX8]

You didn't look hard enough. There's an awesome tutorial full of pictures and even for the same car. Its in the tutorial section or google skyline cleaning aac valve. Your ignition system won't be the cause of hunting.

[Exodus01]

ok thanks, ill try find it.

Edit: ok was searching Auxiliary air valve which is why it was hard to find.. AAC search was great!

Edited August 24, 2013 by Exodus01

[Dose Pipe Sutututu]

Is it running an aftermarket bov?

Have you tried unplugging the O2 sensor?

[Exodus01]

all stock, bought a new Genuine O2 sensor for it from Nissan thinking the same thing, no difference.

[space_monkey]

Hunting during idle is typically due to additional air getting into the system which the air flow meter isn't registering. This is due to a leak somewhere.

The most likely culprit is the black charcoal box that they have to install when importing for emissions reasons. One of the hoses that comes out of this feeds back into your plenum. If you plug the hose with a ball bearing and the hunting stops you've found your culprit. Other points to check are the multitude of vacuum hoses that run around the engine but you don't often see these leaking.

[Dose Pipe Sutututu]

and also if the car is running too rich (due to a dead O2 telling the ECU it's leaning out)

[Exodus01]

OK thanks, i am going to go through all of this stuff over the weekend. got a good few things to try

[Exodus01]

OK guys, reviving a bit of an old post, still having issues...

symptoms:

Car is hunting (not always) on idle...

when driving there is a miss (sometimes not consistent)...

when driving revs cut out completely but the boost gauge on the dash says its still on boost (do not need to be driving hard - intermittent)...

Fix Attempts:

Cleaned the AFM

Cleaned the AAC Valve

Changed Spark Plugs

Changed Fuel Filter

Changed Oil Filter

Changed cracked vacuum hose coming off of the plenum (just above the aac - went back to a black box)

Plugged above hose after changing it didnt help

New genuine o2 sensor

I'm out of ideas, the only thing i have yet to try would be coil packs but dont want to spend all that money and it not be the problem. any other suggestions?

[Plattsy]

have you reset the ecu at all? disconnect bat and leave for 24 hours. will drive like shit for about 10-15ks after and take it easy. it will relearn, and always used to sort my problems.

[sleptema]

OK guys, reviving a bit of an old post, still having issues...

symptoms:

Car is hunting (not always) on idle...

when driving there is a miss (sometimes not consistent)...

when driving revs cut out completely but the boost gauge on the dash says its still on boost (do not need to be driving hard - intermittent)...

Fix Attempts:

Cleaned the AFM

Cleaned the AAC Valve

Changed Spark Plugs

Changed Fuel Filter

Changed Oil Filter

Changed cracked vacuum hose coming off of the plenum (just above the aac - went back to a black box)

Plugged above hose after changing it didnt help

New genuine o2 sensor

I'm out of ideas, the only thing i have yet to try would be coil packs but dont want to spend all that money and it not be the problem. any other suggestions?

The miss could be caused by the coils, but I am not sure if it is causing the hunting. If the car has done well over 100k kms, the coils should be changed anyway. A set of splitfires set me back $400 and were easy to install, and should last you another 100k kms and will last with any mods you plan on doing.

Like Plattsy said, try a ecu reset. Although I didn't think it needed to be off for 24 hours, I would have thought 20 mins would be enough.

[Plattsy]

The miss could be caused by the coils, but I am not sure if it is causing the hunting. If the car has done well over 100k kms, the coils should be changed anyway. A set of splitfires set me back $400 and were easy to install, and should last you another 100k kms and will last with any mods you plan on doing.

Like Plattsy said, try a ecu reset. Although I didn't think it needed to be off for 24 hours, I would have thought 20 mins would be enough.

you can do it in twenty if you pump the brakes or some shit. but i always left it for a day to be sure.

[Exodus01]

Thanks for suggestions, ill try resetting ECU.. cars only done 90k kms it was sitting in my brothers garage for 4 years doing nothing prior to coming to me.

[Exodus01]

and does anyone know what it would roughly cost if i took it to JEM or someone to determine the issue?

[Plattsy]

a f**k load. just search on here mate. youll find the issue eventually. and its a much better feeling finding it your self.

[Exodus01]

yeah i know, its just i got an r32 and a r34 so the r33 is gonna cost me to much, id rather fix it n sell.

[Exodus01]

Tried the ECU now, no good still the same. the annoying this is its not consistent, at first it ran well but shortly after started having the same issues. Any other ideas? I was thinking due to it being intermittent it might be some sensor or electrical fault?

[Exodus01]

OK, car ran good for about a week, played up again, ran good another 2 days, played up and now seems to have a constant issue of the car starting to drop revs when i go above 2500 RPMs in any gear. If i stay below the 2500 the car is running fine.