R33 Spitting Issue

[chubs]

Hey guys I have a 97 R33 gtst with a slight spitting issue. Not sure what rpm exactly it generally starts doing it at either as tacho not working atm.

Last time it was doing this I went out and bought a can of MAF cleaner and this seemed to remove the issue however it has returned and I cleaned the AFM again today but no effect.

Im sure some will say coilpacks but when it happens its not always at the same rev range, and is not constant ie i can floor it and it will go ......put put then hammer on fine.

Should i just get a new afm or would it possibly be my 02 sensor?

Car has the following mods

FMIC

Turbosmart Boost T (set to 10psi)

K&N Pod

Jasma cat back exhaust

(also is due its 100k service just waiting on cheque to arrive so hopefully can have her running perfect again soon)

[hisoka]

i would try the following.

reset ecu. might be running the car rich with old settings.

borrow mates MAF sensor first of all. see if its your maf.

check your spark plugs might be goneskies.

drop boost back to stock and see if it still happens (although not sure what this one will prove)

stock ecu has a o2 sensor diagnostic doesnt it, did you try that.

or if anything your car is just running bit rich with those mods

[chubs]

Yeah im hoping to borrow one at somepoint over the next week. Strange thing is it doesnt smell rich (although i had forgot to actually plug the AFM back in this afternoon when car was idling to warm up to test it and all i could smell was fuel)

Spark plugs should still be good only done not long ago but will check to be sure.

thanks mate.

[DVS JEZ]

try gapping the plugs to .8mm if you havent already.

[chubs]

pretty sure they are gapped to 8mm may be 7mm cant remember will double check. Sparkies were replaced just after Tpiece was done

[MY308U]

hey mate i had the same problem in mine, couldnt fix it for the life of me.. replaced the o2 sensor, coils and plugs, nothing fixed it then i had the motor out of the car for about 3 weeks when i but it back in the problem was gone!! ended up the ecu was playing silly buggers with me, thats where i would start.

Alan

[chubs]

Ok well just attempted an ECU reset ( if i remembered correctly i only had to disconnect positive terminal). First pull through second was perfect. I then noticed a slight splutter accelerating in 4th and then further pulls in 2nd problem is still there.

When i reset the ECU i disconnected positive terminal turned on headlights and sat with foot on the brake while i had a smoke or 2. (this should be long enough yeah?)

Will try lowering boost and see how that goes.

Also with tacho not working cant specify rpm it occurs but in 2nd it was at 60kph and in 4th was around the same.

Edited April 5, 2010 by chubs

[chubs]

ok well have tried lowering boost to. Doesnt seem to affect it much.

Can water in fuel cause this problem??? As when i changed fuel filter back in feb there was a bit of water in there not alot but still there??

Am i right in assuming its not coilpacks though? I figured if it was them it would be more of a constant thing rather than just a quick splutter?

So left to be done is try another afm when i can get a hold of one and to check plugs.

Any way to check 02 sensor or just have to replace it?

Any other things you guys can think of its driving me up the wall trying to work it out.

Also not this generally only happens under hard acceleration.

Edited April 5, 2010 by chubs

[paulR32gtr]

Your O2 sensor would only come into effect when cruising - closed loop mode.

So it only happens when under hard acceleration - so under boost.

I would expect AFM problems to show up under all conditions - but seeing you cleaned it last time and it went away you will need to get your hands on a loaner to test it out.

I would also be looking closely at the plugs - I had a similar problem in my evo - chucked in some new pre-gapped NGK iridiums and problem gone.