When ever i put my car into gear and i just rev it to like 3-4k rpm, i get a really loud backfire but if i put it in neutral and i rev it i dont get any back fire. I dont get back fire when im driving either so im confused. Also it works in any gear if that helps.

I just have a TBE and a protune on my car

 

rich?

 

It's usually random for me. Sometimes it backfires and sometimes it doesn't. I also noticed different exhausts backfire more than others.

 

according to wiki:

Causes

Exhaust system backfires occur in engines that have an emission system malfunction, like an air injection system diverter valve problem, an exhaust leak, or when the catalytic converter has been removed. In some high-performance vehicles, when a driver shifts up and lets off the accelerator, the engine has a moment of running rich. This causes an incomplete burn which causes the fumes to explode in the exhaust system along with an audible clacking sound. However this condition is a result of working smog equipment, and is unlikely to cause any damage.

A fuel injected engine may backfire if an intake leak is present (causing the engine to run lean), or a fuel injection component such as an air-flow sensor is defective.

Common causes of backfires are:

Poor or unregulated engine timing is often a cause of intake backfires, but can also be responsible for exhaust backfires
Improper wiring in the ignition can also lead to timing issues and backfires
Low fuel pressure, clogged fuel filters, and weak fuel pumps could cause a severe lean air-to-fuel ratio during fuel injection
Missing or damaged catalytic converter can result in backfires out the tailpipe

 

Is it an actual flame or just a pop? If it's just a pop, I believe it's the quick change in air pressure coming out of the exhaust... at least that's what a friend told me.

 

Thats weird how it would happen in gear with the clutch pushed in but not in neutral

 

just a pop. But i checked last night and my sister said that she saw a bit of flame near the axel back. Im thinking i have a exhaust leak somewhere??

ya thats whats making me confused also

 

running rich, and it's i believe "after fire"

 

but it only happens when its in gear? Why would it only do it when i engage the gear?

ima just go with this answer lol

 

Backfires are unburnt fuel in the exhaust system getting ignited by the hot exhaust fumes traveling at a very high rate of speed, turbo cars run rich from the factory on purpose cuz they'd much rather have it run like that then catastrophic lean, hence the ****ty gas mileage. You ain't heard **** till you've experienced a SRT-4 bro, now that is a pig-rich, backfiring beast!

 

i know what back fire is and how its created, but my main question was why does it do it only when im in gear..

 

I think the ecu gives more fuel in any gear vs than in neutral, just don't quote me on that, hence the backfiring only in gear, would be my guess. You shouldn't worry too much cuz mine does it constantly, but it could be that i have a straight pipe cbe-hehehe!

 

ive got straight pipe tbe and mine doesnt backfire at all.


The only time my care has EVER backfired was a couple years ago when i had a greddy type R bov. Took it off and problem solved.

 

I'm not an experienced (or even a n00b) tuner, so take this for what it's worth.

I think when the car is in gear, there's more load, so the ECU adjusts a/f and fueling, and all that good stuff. Thus, there's more pressure of air moving, which creates larger differences between pressures, causing the pop.

Again, I'm just pulling this out of my butt, but it all makes sense in my crazy mind.

 

Difference between being in load and not. Simple as that. Or you have a leak in your exhaust most likely pre turbo