I have open BOV and many say that's why it backfires. BUt it's never backfired before. Now, when i let off gas and start slowing down in gear, it backfires constantly.

I don't think it has anything to do with BOV because it should only backfire once when you let off the gas pedal and BOV releases a bunch of air. Plus it didn't use to do it.

So I'm wondering why it would happen now? Could it be because the timing got skipped a notch? What other possibilities are there?

 

Sounds like either SUPER rich condition or exhaust leak sucking in fresh air.

Atmospheric BOV could cause rich condition as the MAF meters the incoming air and if you "blow it off" the ECU still thinks its there and adds fuel accordingly.

 

Yea, I know that about BOV. But like I said, nothing has changed in my setup. I"ve vented all this time and never backfired like this. If I decelerate (let go of gas pedal) with the engine under load (leave it in gear), it'll go popopopopopop constantly until i take it out of gear.

 

how about checking for boost leaks and timing?

 

how long has it been since you have had your valves adjusted. might be time to have it done. especially if you live in the red line. just and idea. or timing.

 

just from presonal expericence when my engine was stock it back fired alot worse then it does now...and it threw alot more flames out the exhuast too...it could be a few things, your open atmosphere bov, an exhaust leak...or you might have blown the inerds of your cat out...welp im sure everything will be ok, good luck

 

yea, I'm pretty sure the engine is fine being that it doesn't burn any oil at all. But i don't have a cat and like i said, have open BOV. but setup has not changed at all since day 1. Maybe it's an exhaust leak? What's the easiest way to check for exhaust leak?

 

Its possible that it was backfiring a little before, and now it blew through your muffler....so you hear it more....

Not likely but definately possible.

Check for exhaust leak by putting car in the air with it running and work your way from front to back listening for leaks and then look at the pipes for black sooty areas where the exhaust has been leaking out staining the pipes.

 

kinda like he said but with a friend, one of you hold a piece of cardboard to cover the exhaust pipe and the other walk under it and listen for a leak. you wont be able to miss the leak this way.