R34 Gt-t Exhaust Popping After High Load+low Revs Then Change Gear

[Scottydoo]

I've only had the car a few weeks but something i have noticed is that if i keep the revs low and use even close to full throttle and change up gears without reving high i hear a popping sound from the exhaust which im assuming is a flame out as the tip is black afterwards. My question is, is this normal for a mostly stock GT-T? I just have a cat-back exhaust/pod filter/plumb back bov. Im assuming that r34's are tuned rich from the factory and this is simply a tune issue of too much fuel in and not enough burnt in the combustion chamber?

Has anyone else noticed the same sort of thing? Im sure its no big deal but just thought i'd ask.

[siddr20]

Yup thats right.. Car is probably running a bit rich!!

That poping noise is normal for our imports.

Unless it full backfires and is fully hecticly loud popping noise then you gotta start worrying..

[Scottydoo]

Yeah i sorta figured it was running rich, im used to cars throwing flames out the exhaust being the owner of a modified rx7

The skyline is only a fairly quiet pop so nothing major. I guess its time to start planning some mods to be ready for a computer and a tune...

[r33cruiser]

just throwing a tagger on here mate.

i can adjust my fuel pressure so i can adjust the backfire.

atm i just have a slight pop/barble on deceleration.

but when really rich it BANGS!!

how bad is it seriously.

[Simmo1985]

I've only had the car a few weeks but something i have noticed is that if i keep the revs low and use even close to full throttle and change up gears without reving high i hear a popping sound from the exhaust which im assuming is a flame out as the tip is black afterwards. My question is, is this normal for a mostly stock GT-T? I just have a cat-back exhaust/pod filter/plumb back bov. Im assuming that r34's are tuned rich from the factory and this is simply a tune issue of too much fuel in and not enough burnt in the combustion chamber?

Has anyone else noticed the same sort of thing? Im sure its no big deal but just thought i'd ask.

Yeah it could be running rich. You could also try resetting the ECU, see if that changes anything (disconnect battery, press brake to drain remaining electricity in system, reconnect battery).

It's nothing too serious if it's only the occasional pop. When you start getting major hesitation and backfiring around the 4000-5000rpm mark you need to start replacing stuff, usually the fault comes down to spark plugs need replacing or re-gapping, coil packs, o2 sensor, fuel filter, fuel pump.. the list goes on - common problem with lots of common causes. Your occasional pop could be early warning signs of the above. Only time will tell.

[Scottydoo]

Its not loud or bad, its barely noticable really, im just used to listening for stuff like this. It doesnt do it on deceleration either, well at least i havent noticed it do it. Only when shifting up with low revs after having some load. And its not a loud bang, just a light pop. And there's no hesitation at all, it pulls quite smoothly.

The motor seems in pretty good condition too, just had all the belts replaced from 100k service, and new sparks plugs (mayb i need to gap them correctly?), oil, etc.

Edited December 3, 2007 by Scottydoo

[silversr33]

Sounds similar to an extremely common problem. It's doing it as you first accelerate, you go through a zone where it's stuttering or popping and not building boost well then it's back to normal until you slow down again?

Running slightly higher than stock boost?

It probably is running a bit rich, would also explain the blackened tip, but it shouldn't - depending where you intend to take the car I'd be thinking about a A/F addon or better yet an ECU that can manage A/F ratios and get sorted out properly on a dyno.

[R334door(s2)]

Sounds similar to an extremely common problem. It's doing it as you first accelerate, you go through a zone where it's stuttering or popping and not building boost well then it's back to normal until you slow down again?

Running slightly higher than stock boost?

It probably is running a bit rich, would also explain the blackened tip, but it shouldn't - depending where you intend to take the car I'd be thinking about a A/F addon or better yet an ECU that can manage A/F ratios and get sorted out properly on a dyno.

my car pops when i just let the accelerator go when im goin down a hill should i be worried ill replace my plugs just incase

[R334door(s2)]

any one?

[MBS206]

any one?

No, every single car will do it.

It's just slightly unburnt fuel in the chamber exiting and igniting in the exhaust.

[delljit]

No, every single car will do it.

It's just slightly unburnt fuel in the chamber exiting and igniting in the exhaust.

will a different gap on plugs reduce it? mine does it a fair bit and currently has 1.1mm gap ngk iridums (i believe thats the gap straight out of the box anyway)

ill probably get it adjusted to .8mm when i take my car in for some diagnostic dyno to solve my power cutting issue

[Simon-S14]

could be a hole in a gasket somewhere letting air into the exhaust and causing a popping on decel

[Scottydoo]

Mines not popping on decel, only acceleration. I dont think its anything, just a bit rich i reckon. If it gets worse i'll start worrying but till then it can wait until i get a computer and a proper tune. Might gap my plugs for the hell of it in the meantime even tho it probably wont stop it.

Thanks for everyone's input btw

[icftoo]

My R34 GT-T "pops" backfires mainly when cold if i accelerate hard then it happens as i decel. So i try to ease her in until she's warm. Doesn't happen when warm.

[Scottydoo]

Mine has been doing it when both cold and warm. The car is running stock boost btw.

I put in some Nulon Performance Engine Treatment E20 in the car yesterday and since I did i havent been able to get it to pop at all even when trying to force one out. Seems to have done the trick, and the car is idling smoother now too Not bad for $13. So yeah, so far so good hopefully it stays that way. Maybe worth a try for you other guys?

*EDIT* Still does it sometimes, but nowhere near as much. Leaves less black on the tip of the exhaust than before though.

Edited February 21, 2008 by Scottydoo