New Mufflers, Loud exhaust backfire.

[89gtVert]

I went from borla to flowmaster because I need to put the stock H back on and still want to be kinda loud, I got on it on the way home and it sounded like an explosion under my car. I know im running rich but this never hapened with my borla. What should I do? thanks, Ryan.

 

[89gtVert]

Also the check engine light pops on and off occasionally, please help.

 

[Henceforward]

Part of the reason you are hearing popping, or backfiring, it because you are running a crossover pipe with no cats. Cats help burn off most of the gas.

Without the cats on your off road pipes you are going to have to deal with that.

Flowmaster has no material inside the mufflers either. Just metal baffles.

When I start up sometimes if I get on it right after I turn it over, it will pop once.

Get a CAtted pipe and it won't pop.

 

[CManT1914]

If you engine is cold when you're driving, it may backfire some. Mine did when I put the 180* t-stat in, because the engine could never warm up. I put the stock t-stat back in, and it hasn't backfired since. Was your engine cold at the time?

 

[PonyBoy90]

I get this also. It happens one cold start-ups, especially when it's cold outside. I'm running a high degreed cam with only 2 cats with a MAC 2 1/2 inch catback system. Once warm though (after a minute of idling), I can step on the gas and it won't pop. I'm running rich also.

 

[tonydalrymple]

Something to check although it probably does not apply to your situation.
If you have an exhaust leak before the O2; backfiring often occurs.....