Nistune Forums

what causes it and how to i get rid of it? im assuming there is some fuel getting into the exhaust when i let off the gas. basically when im in gear and totally off the gas i get some loud popping and backfires through the exhaust. are there changes i can make to the fuel cut or fuel recover tables? is there a mechanical problem?

the car is intercooled, hybrid turbo, dsm 450cc injectors, z32afm, vg33. i never noticed it until i removed a second muffler that i had in place of the converter. now i just have a straight 3 inch turbo back exhaust and a magnaflow muffler in the back. the car runs fine otherwise, but its kind of annoying and id like to get rid of it if possible. please give me some ideas of some things to check

What k value and Latency are you using???



You need to mess with the Fuel Recover/Fuel Cut Tables... thats what causes the popping...

It occurs when the ECU recieves a TPS "on" signal, it will access the fuel recovery and cut tables, as well as the Idle timing table.


Good luck.

Chris you should give me a copy of your tune for me to look over.

as he said... fuel cut/recover tables

You are getting unburnt fuel going through and being ignited afterwards. Especially noticable if you dont have a catylitic converter or any other restrictions in the way

I have that same popping and backfiring happening...

dont find it that annoying but i think the cops do.. lol

in order to avoid leaning out or doing something wrong...
should u raise those values in the fuel recover/fuel cut tables or lower them ?

Man I love that popping and burbling on the overrun, I have no idea why you'd want to get rid of it. In my opinion it's one of the few perks of free-breathing exhausts, unlike the incessant drone at highway speeds.