Ok so about ten minutes ago I was driving down the street and turned a corner in 2rd gear...i then hit gas exiting the corner got to about 21lbs of boost and suddenly heard what sounded like a backfire...I have never gotten that out of my car before. I parked it for like 20 minutes while talking to some friends and then I drove it again and the same thing happens...only this time it sounds like automatic gunfire when I hit boost...Im really nervous about this, obviously! I just had it tuned at AMS in chicago at 324 hp and 303 for max torque, I have HKS 272 cams, 680cc injectors, EVC at 23.8 lbs of boost, full buschur exhaust with test pipe, buschur intercooler,buschur IC piping, and buschur Intake...stock head stock block, stock manifolds, and turbo...If anyone has any idea what the hell is going on with my car that would be awesome...Im going to call AMS in the morning since they tuned it and by the way it was running fine until that first "backfire"...thanks in advance

 

have you checked for an exhaust leak? i forgot to plug my wb bung up one day and it backfired

 

Im pretty sure I dont have a leak but I dunno Its dark out so I will check tomorrow but it only happens under boost...I wonder if its spark plugs but that doesnt make any sence either becasue it just randomly started doing it

 

I'm guessing it's because you're running catless and the mixture richens up once you hit boost.

 

I should maybe mention also that ive been driving for about 2 weeks since the tune with no problem at all and even took it to the drag strip the day after the tune with about 10 runs with no problems...

 

Im at 11.4 afr under load

 

When was the last time you changed your plugs? Which brand?

 

I was just thinking about that since I dragged it Im gunna change my plugs tomorrow morn...spark blow out hopefully...im gunna call AMS in the morning and see if they have a recomendation for gapping for their custom tune...

 

That just really makes me nervous becasue I bought this car used and as soon as I bought it the motor blew becasue the person that owned it b4 me drove it with blow by and it sent a rod through the block...sooo i dont wanna do that again...unless i decide to finally stroke it

 

ttt

 

Sounds like ignition issues.....good luck.

 

im about to change the plugs so hopefully this is all that i need haha

 

What kind of plugs are you putting in? I would suggest NGK BPR7ES

 

Make sure and gap them, I think about 22 to 25 for the gap, I dont remember off the top of my head....... maybe someone can post if they know for sure.......

It makes a world of differance!

 

Had the same issue... spark plugs where not gapped corectly, sounded liek auto gunfire in heavy boost too!..spooky.... I got NGK bpr7es gapped to .026 .. solved it. IF that doesnt do it for you i suggest going to .024.