Do your cars Backfire?

[vadem]

Got my beast running good, a couple of days ago. At first before it was tunned it back fired alot when I let off the gas. But I thought that was because of the richness, after we tunned it with afc and wideband, it still does it. When im crusing in 5th and let of, it will throw 2 foot fire balls out back, and blow so hard it almost made me soil my undergarments. Its tight nonetheless, but im worried somthing or someone can get burned back there. Im sure if I had a cat it wounln't do it, but can I reduce the backfiring from tunning? My guess is it b/c of my open bov, it gets rich at shifts, then backfires? Do you guys have this problem?

[tony/ka24de]

mine bacefires, but not as bad as yours does, I'm using a cat and open bov. I think its the open bov too.

[daniel240]

mine does too, although im not sure if it shoots 2ft fireballs out the back like yours. i know im running rich and that is probably one reason. but i have heard that most kats backfire a little. mine seems to do it when it warms up. i also have straigh 3'' piping w/ no cat.

[ultimatuc]

mine does this to. I think its either an exhaust leak, or timing problem. are you running the jwt ecu?

I'll post back when I figure it out.

[AN89HATCH]

Is there a way to controll the backfireing/ fireball?? Im also going to be running an open blow off valve. Lets say a cop gets behind you, I dont think he would be to hapy to see a fireball shoot out your exhaust :pface

[vadem]

Its controllable, its not like out of nowhere, it starts blasting. Say if im crusing at like 30 mph, if its in 4th underload, even if I do let off the throttle, it almost never backfires. But in 5th it, usually will.I also have 3 in downpipe, to exhaust.

[andrave]

mine backfires loud and its non turbo with the stock resonator still in place. and the cat.I rule.

[LongIsland240]

Have had more than one person say to me at a light, "Hey man, your car is blowing fire out the tailpipe!...is it supposed to do that?!" Don't know if they're of the two foot variety, but big enough to get peoples attention in broad daylight......i've got a hollow cat and open bov, running stock timing with boost retard @1/2 deg per psi.....backfired more with timing retarded from stock....

[C-Kwik]

Chances are it's the open BOV causing it.

[HolyShiznit]

My car backfires, I have straight 3 in DP to a 3 in test pipe to A'PEXi N1 Duals. I have an open atmosphere BOV. Mine doesn't through fireballs, at least no one has noticed them. But then again I am fully tuned so I dunno. However, with the open BOV and the SAFC w/ Dec. Air set-up you WILL backfire no matter what. Some of the other cars in my area do the same thing.

[vadem]

What are your dec air settings, mine is like .6%.

[sil80drifter]

i want 30 ft fireballs, so I can burn the ricers behind me....what SAFC setting do I use?

sil80

[bustav13t]

would you still get fireballs if you run a resonator?

[AN89HATCH]

Would you back fire with a blow through mass air flow, and an open bov?

[Jookmasta]

so is it the jwt ecu causing it in conjunction with the open bov? or just richness + open bov?

[Red-KAT]

I get slight backfire...

I Like letting off the gas in seconds around 2k rpm's

makes lots of little pop's in the exaust.

[bustav13t]

hah, i get lil pops after letting off the gas at high rpms from just removing the pair valve on my stock n/a

[bokinsmowls]

exhaust leaks are common fireball culprits

[MikeMurphy]

I thought it was the coolant temp. sensor, but now I am starting to think that it is the fuel pressure regulator, or the hose that connects it to the manifold.

I will post up results as soon as I have it diagnosed.

[MarkEmark]

Have had more than one person say to me at a light, "Hey man, your car is blowing fire out the tailpipe!...is it supposed to do that?!" Don't know if they're of the two foot variety, but big enough to get peoples attention in broad daylight......i've got a hollow cat and open bov, running stock timing with boost retard @1/2 deg per psi.....backfired more with timing retarded from stock....

Mine doesn't backfire much, it does it almost undetectably under vacuum slowing down with the clutch in, it's just a low grumble, maybe not even backfiring.

The time it does it really loud i've noticed is usually shifting between 4th and 5th, and under VACUUM, or if under boost, only a tiny bit. It doesn't do it much though. A girl was following me the other day that I knew and she was like "did you know your car shot out flames when you shifted?" I was very surprised, I didn't think it'd have actually shot out flames, but I think it's pretty cool...reminds me of a race car, even though the fact that it IS backfiring means there's room for tuning. I'm running 2.5" exhaust all the way back, no cat, tanabe resonator and muffler, JWT ECU. But man, sometimes when it backfires, it's a loud as a gunshot...makes me jump sometimes.

[fiznat]

what does an open BOV have to do with backfiring?

[sil80drifter]

actually, tuning and backfiring can still be united, you see when you're running rich your flames are orange or reddish, but if you lean the crap out of your car, your backfires will be more blue in color (indicates the increased temperature fo the mixture), or a mix of yellow and blue. a lot of GT class cars can be seen having flames trailing out of their exhausts, and you KNOW they are as tuned as can be.

when the bov blows off to the atmoshpere, this richens out the exhaust mix a lot, as less air is combined with mroe fuel in that particular engine cycle, so you shoot "rich" flames or bakcfire a lot. and vice versa for the blowing off back into the intake.

sil80