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.

 

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

 

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.

 

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. 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.

 

I installed bhr ignition with my high flow cat, borla exhaust and greddy turbo. always backfiring and popping. sometimes so loud it sounds like I blew something.

Posted From RX8Club.com Android App

 

Do ya Think it might be your tune

 

Could be. I bought the car from an old man with 47,000 miles in mint condition. All mods were professionally installed by Dyno comp in Scottsdale AZ before I bought it except the BHR kit which i installed myself. I have every single reciept for the car for literally everything since he first bought it in 2004 and he said it was tuned when he installed the turbo bout 6 yrs ago.

 

hi everybody.

first of all i want to appologise for my englis, im french. i will try to do my best.

i know it's probably not the right place but i can't start a post only reply.

here's my problem:

i build a 04 rx8 for road race. the car as 34 000km and everything was fine on it. a build the car and than put it on dyno to tune it. after that i've always a black smoke Under compression as soon as a lift throttle to brake. sometime it's fire but more often a lot of black smoke and the series official did not like this and other driver too. sometime it light up but more often it was smoke.

heres my mod:
13 b renesis short block factory stock with 34 000km ont it
AEM cold air intake
73mm throttle body (need wire system to fit on my wilwood pedal assembly)
custom equal lenght headers and 3in straight pipe exhaust line
adaptronic e440 standalone ecu
gm ignition coil
runing premix 100/1 and i have tried 200/1 like gulf competiton recommand me but it didn't change anything.

i'm good to build race car but not to tune it. i went to my friends dyno shop. when i ask im if he plays with split timing he said that a dont need that because i dont have enough power. maybe it could be a good info for you pros.

the base map was provide by adaptronic

can somebody help me to resolve this probleme ??? i would like to have fire insted of smoke !!!

 

You are catless, so there isn't much you can do about it. Backfires, flames, and smoke are all going to happen. You can limit them some with a proper tune, but you will never be able to eliminate them.

Getting a good tune will be important regardless, and I recommend someone that knows what they are doing with a Renesis.

 

i was catless before turning it to race car and i nerver add smoke like this only light up often but no smoke. the smoke is pretty massive. i've seen other rx8 running almost same setup as me and i didn't smoke massively like this