bandit383

iTrader: (8)

All right so I've got a 2001 trans am with a ls7. Car ran fine till the trans acted up so I pulled trans and dumb me left the plugs out and in Va that's not good.. So long story I had to pull heads, rods and pistons. Cam crank and timing chain stayed in motor... Every thing was torqued and lubed as required. So fast forward everything gets put back where it belongs and motor started right up.. So awesome put trans back in and that's where this story goes wrong... The car started but would backfire through exhaust for a min or so and clear up.. Then it would start up day one and run just fine. Then next day no good backfiring and glowing the headers ( dumping raw fuel in headers). Then start up just fine without changing a damm thing... So on so forth till one day it will start and run for 20-30 seconds then stops running and when it refires it will just back fire and glows headers.. I've cked all the small things grounds on the back of the head are good ( cleaned both head and terminals) , cked the plugs all was good, ck the tune. Even adjusted the lifter preload ( yes LS7 rocker arms are adjustable). Then I adjusted the tune put more gas in and took gas out, added timing (5deg) no changes and put it back to 8 deg. Nothings a miss and nothing has changed. Tune is a speed density so all but a couple of sensors are left. I have pin cked both the cam and crank sensor harness all was good. Put the PCM in another car and all was good. No water or fuel in oil. 60 psi fuel pressure. 40-60 psi for oil pressure. No odd or funny noises. Car doesn't run hot. Data logged and nothing in there( cam, crank, map iat, tps and injector duty cycle. I am at a loss of where to go next.... So any ideas out there...

Iam Broke

Cracked intake manifold or bad gaskets, sounds like it's sucking air.

bandit383

iTrader: (8)

Nope already cked the intake when I adjusted rocker arms.

bandit383

iTrader: (8)

Any ideas out there.

S10xGN

iTrader: (11)

Sorry, can you elaborate on what plugs and what they have to do with VA?

bandit383

iTrader: (8)

Humidity is close to 60-70% most days there.

Kevin Blown 95 TA

I washed out an engine block once when I lived there, and in a matter of minutes, it rusted so fast before my eyes I couldn't believe it. One of the many reasons that I hated living in Norfolk, Virginia. The locals used to lovingly refer to it as No **** Vagina.

S10xGN

iTrader: (11)

So, you're talking about spark plugs? I was having trouble visualizing what plugs had to do with pulling a transmission. BTW, we're almost underwater here on the Gulf Coast, so I know all about humidity...

Kevin Blown 95 TA

I think he means moisture got inside the engine when the plugs were out.

silverLSWON

iTrader: (16)

Broken inner valve spring or outter valve spring...bent valve...my friend had an issue on his lsx 454 tfs heads and ended up being a few crushed valve springs. But he also found out the installer used the wrong push rod length and you said you checked that.

bandit383

iTrader: (8)

I had spring cked before putting motor back in. However I'll inspect the spring this weekend.

LS1MCSS

iTrader: (18)

If the headers are glowing, it's not because of dumping too much fuel. It's from not enough fuel and the exhaust is super hot.

bandit383

iTrader: (8)

Tried that as well no change..

bigblockb

iTrader: (4)

Are the heads stock Ls7? If so with stock rockers, what makes the rockers adjustable? I have a LS7 in my TA since 07 and the rockers are not adjustable. I had to measure for the pushrods with comp short travel lifters and the rockers are torqued to 22ft lbs. Unless something different was done to the valvetrain stock rockers are not adjustable. And I've had mine apart a few times.

bandit383

iTrader: (8)

Not stock rocker arms... Please everyone not trying to be an *** but if your going to tell me that my rocker arms are not adjustable please move on... For the last time I have the harlin sharp ls7 arm and they are adjustable...

LLLosingit

iTrader: (4)

Timing or lean condition is the usual cause of glowing headers but since yours was intermittent I would suspect something else. Bad o2 sensor maybe? Do you have a wideband to watch AF ratio?

bigblockb

iTrader: (4)

All I read in your first post was LS7 rocker. Don't see anything about them being Harlan Sharp. Reread a few times as age is winning its war. However,
here in Fl. humidity plays hell on the injectors when left sitting. I have seen them have problems after sitting. Just a possibility. Good Luck.

jb72

Hi. Had similar symptoms in my '04 vette. Replaced both pre-cat o2 sensors and fixed the problem. Pcm never latched a code and the troubleshooting drove me nuts! Good luck and hope this is your problem.

MuhThugga

Make sure you didn't pinch a sensor wire somewhere. If you have no vacuum leaks at the intake, I would suspect that a sensor has crapped out or a wire is pinched causing a sensor to short out. Start at the upstream O2 sensors and work your way on up.

Were the heads disassembled so the valves could be inspected for rust buildup? I had that happen on an LT1 that sat for a while. It would backfire and sputter at idle. We just cranked the throttle for a bit and it cleared the rust right off.

lol

It took me a moment to figure it out, too. I was thinking, "Why the **** does the state of Virginia care about leaving spark plugs installed in an engine while work is being performed?"