So i just bought and injen up pipe and down pipe and had a greddy exhaust put on my car. i had the downpipe and the exhaust on first and everything ran great. then once i had the uppipe in everytime i let off the gas it backfired, and same thing when i downshift and let the tranny slow down. any ideas on why this is doing this ?

 

do you have a aftermarket BOV installed?

 

no just the stock one

 

not sure. maybe you have a leak and its causing you to run rich.
Are you catless now?

 

ya its catless, which i think could be part of it but i dont think it should be backfiring everytime

 

you may have a leak.

hopefully someone with a little more experience can help out.

 

duh....catless there problem solved

 

well ya i know that the problem mainly is because it is catless, however i talked to someone who has the same down pipe and up pipe and he said it shouldnt be doing it as much as mine does

 

running any engine management?

 

its fine nothign toworry about

 

weird...yea it shouldnt be backfiring every single time....

 

been catless for about 5 months and only time I backfired was with a atmostpheric BOV on the car.

 

Do you have an intake of any type?
I'd recommend resetting the ECU at a minimum.

(Disconnect negative battery terminal, step on brake pedal. when you reconnect the terminal cycle the key to Accessory about five times (this allows the ECU to get some base readings) once done with that start the car and let it warm up).

Take it for a drive and see if that helps. May be the car hasn't gotten used to the mods you have done.

Other than that, recheck your install. Make sure the O2 sensors have been reinstalled.

Could be a gap in the gaskets on any part of the exhaust, recommend looking/listening for leaks at the flanges of the exhaust pipes.

Not sure what else could be causing it to back fire so frequently.

 

the backfire is more common cause the cat was removed and doesnt soak up the fuel. u normally spit flames when this happens. depending on engine load you will notice it more. using the tranny increases the load so u'll hear the bf also sudden release of the throttle after long periods of throttle usuage is another common occurance. ever watch a race car at the track. same thing is happening

 

no, not really, I've been running full catless for well over a year. Its the STi's that are known to backfire a lot, not WRX's