iwanski

Lm7, Truck Norris, CAI, shorty headers

Still sorta new to everything, backfiring only happens on Bank 1, not up to temp.

What’d be your initial thoughts as to the cause
Bad tune, bad gas, bricked o2s, something internal within the valve train?

What would be your guys first step to diagnosing this backfiring?
Would gladly provide more info

https://youtube.com/shorts/SlgCiYtvv2k?si=hInRiX5MsiJ4Fou-

iwanski

Sometime today I’m planning on swapping coils across each bank and O2s to see if I either are bad, I’d also like to check the cam sensor and wires

It’s got new MAF and o2s, crank and cam sensors are original with ≈175k in them so I think they could potentially be shot.

JacobChevys

Check coil harness to make sure you didn’t cross any while you plugged em in

iwanski

Quick update - It’s a misfire on cylinder 3 unplugging spark plug on it remedies the backfiring.

I actually took C1 and C3 plugs, wires, and coils, and swapped them but no change so it’s leaving me to believe this is a fuel (injector) problem?

iwanski

I know I’m basically carrying my own thread, just figured I’d share my findings throughout the process

I undid the valve covers, no bent pushrods, all still 22ft lbs, they’re opening and closing.

Whats made me believe it’s an injector problem on C3, is that in the process of richening the fuel trims for the misfire, how is it that C1 has a rather carbon covered plug, but C3 has near none at all?

More or less the brain process I’ve gone thoufh to find this

GMRL

Theres no chance that the injector connectors are swapped?
​​​​​​Also check for bare wires on that injector, if there is a short to ground, it could cause it tor randomly open.
​​​​​​Any codes?

Che70velle

iTrader: (6)

How do the spark plugs look? Was this professionally tuned?