I just replaced the engine on my 2005 RX8 (6MT) with a second-hand one (drove into a pool of water and jammed the rotors).

After installation I had a persistent misfire which was solved by replacing a coil. It now revs out cleanly, but backfires when backing off the throttle. Any ideas what might be causing this?

My 8 does the same thing it's perfectly normal.

Backfires are great. Mine dose it also .. Its all stock ATM .. don't worry about it.

Mine can pop 2 or 3 times when coming off throttle. The only exhaust mod is a catback.
It's normal.

Yey its norm

yea, people are always asking me "why does your car do that popping noise" they always assume its horrible timing lol.

yea, people are always asking me "why does your car do that popping noise" they always assume its horrible timing lol.

This is not a pop-pop, it's a loud backfire. Could this indicate that the seals are damaged?

^^ NO.

Mine backfires and shoots flames. Pops LOUDLY.

Normal for a rotary.

means maybe you have a wiring problem with your fuel or a bad cat for buildup of fuel to have such a backfire. (engine pushes excess fuel into exhaust pipe, exhaust flames ignite excess fuel)

I look forward to the backfires ^ I think it happens less with my MM AP tune though heh.

As everyone has said...I get 2 or 3 pops every time I get off the throttle and it is to be expected. You would have noticed these before, unless you did a catback install when you did your motor. Although...I guess it is possible that something happened to your cat when you ran into the flood that is making it worse for you now. Have you tried taking apart the exhaust system from the engine back and making sure that nothing was damaged or died up in there while the car sat?

p would just like to put my .02 in on the jammed rotors of the original engine. its actually nigh impossible to hydrolock a rotary. i bet dollars to donuts that original engine is just fine and in need of a good drying and lubricating. you wouldnt even need to pull it to get it working again...

lol jammed the rotors=no start

p would just like to put my .02 in on the jammed rotors of the original engine. its actually nigh impossible to hydrolock a rotary. i bet dollars to donuts that original engine is just fine and in need of a good drying and lubricating. you wouldnt even need to pull it to get it working again...

We tried everything we could think of. Couldn't even turn the engine with a spanner!

I'll try pulling the exhaust system apart as well as disconnecting the cat system.

What is a "spanner"?

a wrench

i've only heard mine backfire twice. It sounded like a gunshot. I have a supercat and a sp2. But the normal poping is awesome.

Althought when i get the really really loud ones, it even startles me. lol.

:dunno:

After being surrounded by rotaries for a couple of years, i truly believe the flatulence (popping/backfires) is normal.

Revving high then letting off will cause it all the time. :lol: I can't imagine what you'll think if you ever upgrade to a midpipe or hi-flo - haha - watch for "back-FIRE" then lol

Clean the MAF.

New coils from BHR make the spark much hotter so it isn't so rich. Reducing backfires.