Hi all, this problem has been going on pretty much since ive had the car. It runs fine in 1st 2nd and sometimes 3rd but most of the time past third gear at 6k rpm I will get the famous backfiring issue that no one can seem to figure out the cause of. The car has:
-street port
-rich mans non sequential conversion
-greddy 4 inch turbo back
-greddy intake
-greddy fmic
-Pettit "unlimited" ecu
-aem 320lph fuel pump
And a couple other small mods. Half of me thinks it's the ecu, the other half makes me think bad injectors. Ive been told it could be fuel pulsation dampener as well as leaky injectors. I'm about to purchase an msd 6a ignition amp to see if that helps fix the issue. Ive searched off and on for the past few years and the search always yields different results, so if anyone has some input id love to hear it. Thanks everyone.

 

It could be several things, but you'll need to do some work or get some monitoring to know for sure. A few things:

• Yes, the Pettit ECU runs rich. Using a programmable ECU would allow you to tune it to how you desire
• Yes, it could be the injectors but you'll have to pull them and send them off for cleaning to know (and that may not be the cause). Not a bad idea to do if you don't know when they were last serviced.
• Your aftermarket fuel pump could be overpowering the stock fuel pressure regulator (since you didn't list an aftermarket regulator).

When this backfiring happens, does the performance of the car decrease?

 

I installed the pump a month ago thinking it would help the problem, but when messing around with the car after install I noticed the boodt controller settings were messed up (the "sharp/mild" function of the controller confused me) causing the car to fumble a lot more. With the settings adjusted it fumbles less but still fumbles. And it does decrease performance when it happens. Like it can't make it past 6k rpms because it stumbles. I forgot to mention that my car will backfire 5 seconds after I turn off the engine which ive been told could be a leaky injector. Thank you for the reply.

 

Yes, could be an injector problem. You won't know until you pull them and have them benched. Even if they aren't the problem, it's not a bad thing to do.