stockLT1

My car is backfiring out the intake, what can cause that besides plugwires being out of order??

Just looking for other possible causes, Just to be sure I don't miss anything.

Thanks in advance..

ajschult

Timing chain being off a tooth or more. Also improperly adjusted rockers.

93transam1234

That would happen to me when my fuel pump was going out, might want to get a gauge on her and test the fuel presure

ajschult

Just curious: have you done any work on your car lately?

stockLT1

fuel pressure is fine, timing chain is fine.

I went to 42# injectors.

96' harness

94' PCM

Got a new tune, but backfire is still there, just pops real loud out of the CAI.

No vaccuum leaks either.....

stockLT1

Checked rocker arms, changed plugs, and checked compression/ leakdown recently aslo.

93transam1234

recheck that all the plug wires are going to the right opti port?

What kind of Inj. did u go with? why did u need such big ones?

stockLT1

Ohmed out plug wires and made sure they were going to the right cyl. All checked out good.

I needed the 42#'s for 396ci, 12:1, 300 shot N2O

stockLT1

Any other Idea's guys??

ak_WRX_Z28

is the intake backfire bad on the engine? i just put a trick flow elbow and now the backfire sound is louder. what's causing it? we just had it tuned up last year.

Polo-94Z28

I had a backfire out the intake ... long story short, scoped everything on the car with a dso... turned out to be the opti, installed a new one, problemo solved. Also, my misfire was only at a certain RPM... If that helps at all.

BLinindoll

mine does it too but only when letting off at about 6000 RPM's. Could it be caused by tired valave springs which would cause valve float? I have new plugs, new coil, new wires, new MSD ignition. Hope it's not the opti. I could settle for the tired valve springs because I'm doing a Hot Cam Kit right after I do headers, which hopefully isn't that far off in the future. BTW, 96K miles.

Polo-94Z28

You sure youre not hearing the exhaust... Ive got 133k on the clock and I dont get any intake backfires, not even after letting off at 6k. Then again, I don't let the throttle slam shut and leave it in gear. If you do that, then you get the exhaust popping sound.

30696bird

I also had the same problem/ same results.