A pretty well versed rotor mechanic mentioned that some small backfires can be caused by faulty exhaust gaskets that, upon deceleration (or shifting) air gets sucked in the gasket leak and makes a mini explosion...thus the backfire.

Is that correct? .... or....

I always though that small backfires are caused by the car running very rich, so rich that significant unburn fuel makes it to the exhaust during decel or shifting and blows up in the exhaust...thus a backfire.


....anyone want to validate either of these?

 

An exhaust leak could be the source of a backfire, yes. Under significant vacuum, like deceleration, the leak could be the source of air entering the exhaust system.

Kyle

 

ahh, thanks kyle....so I may be able to reduce some small backfires by replacing all my worn gaskets and making sure I get a good seal between downpipe-cat-catback

 

If your gaskets are, in fact, bad, then yes. If the gaskets are still sealing well, you obviously won't see any changes. Good luck.

Kyle

 

thanks

 

I don't think you'll completely get rid of your backfires if you have removed the pre-cat. I believe you'll still have some backfiring.

My backfiring reduced quite a bit when I did my normal maintanence over the summer (O2 sensor, spark plugs & wires).

Still some backfiring on deccleration...

 

Blowing flames is fun though!

 

good point mahjic....so any backfiring that is not caused by air leak is caused by too much fuel?

 

LOl leprechan :-)

 

Well, honestly, I have no technical data for this topic, only guesses and theories...

I think it's caused by both, running rich and removing the cats. Our rotaries run pretty rich in stock form, however you usually don't notice any backfiring until you remove at least the pre-cat.

I know I never heard any backfiring on my car until I did my exhaust upgrades. I've also read about people programming less fuel upon deceleration to reduce the backfires on programmable ECU's.

 

>>I've also read about people programming less fuel upon deceleration to reduce the backfires on programmable ECU's.

ahh, thats what I like to hear, .....I plan on going to a larger IC and apexi power FC in the next year, maybe I can tweak the fuel deliver y to eliminate the 'pops' :-)