robert21122

I just refreshed my ls1, new bearings ect, after about 15miles or so of driving, I decided to give it a little pull. On the decel I developed a backfire coming from what sounds like intake manifold . Cyc 2 was cooler then the rest after drive. Now it doesn't get hot at all. So I checked the coil for spark which it had and i changed it out anyway, I put in new plugs went to a tr5 from tr6s gapped to .35ish, new wires and new injectors, thinking a injector was stuck open, I also checked for exhaust leaks. No new codes or anything. I can't figure this out. i just got my hp tuners up and running and was able to log but i dont see anything unusually but then again i dont know what im really looking for. This is a video of the pops. Is it possible to have a headgasket leak? i am noticing extra exhaust smoke but its blueish white lol. i know blue is oil white is water. i tried to even reroute my catch can thinking thats was the cause of smoke.

C5 Diag

I’d probably do a quick compression check on #2 just to see if it may be something mechanical...with your HP Tuners what do your long and short fuel trims look like at idle ??...did you check the wiring to that injector ??...with key on you should see 12 volts on the pink wire and since the PCM grounds the other wire to make the injector open you can try that...take a 12 volt test light connected to battery POSITIVE and with the injector unplugged and engine idling probe the other wire (striped wire)...the test light will blink verifying injector pulse !!

robert21122

Thanks, I did have it warm up on cyc 2, but it wasn't near as hot as the others when I tried messing around with it today. I'm going to pull the valve covers tomorrow and check and make sure push rods aren't bent and that my springs are still good, nothing sound unusual as far as running though except the random pops

~Josh

I’d check for a broken valve spring, might have damaged the valve stem seal allowing oil in the cylinder to burn.

Broken valve spring doesn’t have control of the valve and allows gas back into the intake port. I’d focus on intake side valve springs.

robert21122

Thank you sir, I was starting to think that after exercising every other option with out digging into, ill be pulling the valve covers today. I do have beehive springs so maybe the second one is still holding it up barely