chevrolade

iTrader: (21)

What else could it be?ive had this issue for about a month or so now...

every time from a dig at wot,it backfires through the cai then runs just fine....
hooked up the obdII was running rich and lean .low fuel pump performan,fpcm as well...hooked up fuel pressure gauge was at 60 then wot it would go down to 30...

so i put new plugs/wires/new oem fuel pump/the fpcm is still bad but tune is dead on and has good pressure now (60)

then i ran into this hoping it would fix





broken timing tensioner....so i put a new one ls2 type with new chain...started it all up and still backfires...any ideas

BLINGOLE

iTrader: (5)

Hold on, your fuel pressure stays at 60psi? Why do you say your fpcm is still bad? If its popping only when you first get into the throttle its gotta be either lean or a wacked out tune with a bad timing cell.
What kind of mods do you have? Also if you have someone that can hook a wideband up and log a run with hp tuners it wouldnt be hard to figure it out.

Is there aftermarket tuning already?

edcmat-l1

iTrader: (10)

Backfire in the intake the way you're describing is a lean condition. Tune it.

chevrolade

iTrader: (21)

just got it wideband tuned and its perfect...the fpcm is bad but doesnt need replacing unless the engine light annoys me but it dont.truck is full bolt on 6.0 l92 heads 231 235 .617 .620 cam ls3 intake

i just did a compression test

90 --- 165
155 --- 180
180 --- 180
180 --- 180
^^
FRONT OF ENGINE