backfires underboost?

[MrdB]

heres is my motor mods.... when ever it builds full boost it backfires like its hitting rev limiter? every gear.. never fails? please some1 help me!

JDM 6-bolt 4G63 engine
.020 over Ross forged 8.5:1 Pistons
Eagle H-Beam forged rods
NGK BPR7ES spark plugs
MSD Super Conductor 8mm Plug Wires
Forced Performance 4" intake pipe
3" GM MAF with MAF Translator
Forced Performance "Red" Model turbo (60-1 compressor wheel / TD06H turbine in a 7cm housing)
2g Mitsubishi Eclipse turbo exhaust manifold with wastegate off #1 runner
Hallman ES manual boost controller
Ported 2g o2 housing
29x10x3 spearco front mount intercooler w/custom 2.5" stainless steel piping
USDM 1g Eagle Talon Intake Manifold
Custom 3" exhaust w/3" A'PEXi N1 turbo muffler
Tial 38mm external wastegate
GReddy Type S blow off valve
Precision Turbo 680cc injectors
Forced Performance FP2 (272) cams
Walbro 255lph fuel pump

 

[brute]

Do you have a fuel pressure regulator for that 255? Also, do you have any type of fuel control or compensation for the upgraded injectors?

 

[MrdB]

i have a maft setup with a safc... the car runes great.. untill it hits full boost... u think i may have a boost leak?

 

[brute]

I'm not sure. It never hurts to check. A boost leak may cause it to run rich enough to make it backfire. But it'd have to be a huge leak. Does it boost fine? Does it feel fast or like something is holding it back?

 

[MrdB]

its a fp "red" so the spool is slow as hell.. once it hits about 18psi its like i hit rev limiter... its really odd.. i think the timing may be off or a leak... i read 10.5:1 on my wideband

 

[tylermartindc]

maybe check out / replace your plugs.
my car was doing something like that whenever i went past 10lbs and i had my mbc set to 14lbs so whenever i hit full boost it would back fire, or sputter or whatever you want to call it. replaced the plugs and runs like a beaut.
my .02

 

[MrdB]

i change the plug and poof! RUNS LIKE A BEAST!!!!! oh my fooking god.. i recommend a FP "RED" to everyone!

THANKS GUYS FOR THE HELP!!

 

[jumpfroggy]

GJ tylermartindc.

 

[tylermartindc]

nice to hear your cars running wicked, thanks jumpfroggy

 

[No_Skillz]

The plug might have fouled because you're running way rich due to fpr overrun. Invest in an AFPR.