Ok so this is my first build and first time swapping an LS... I swapped the LS1 out of my 2002 Camaro, for a low mileage LS1 out of a 2000 TA. All that was done will be listed below.

PRC 255 heads from TSP
BTR chrio rockers with trunion upgrades
7.400 .080 pushrods TSP
OEM knock sens w/harness (new)
Fast 102 Intake/TB billet fuel rails.
LSA injectors
Comp Cam - 231/242 with 112LSA
new timing chain and sprocket
melting High volume oil pump
Custom steam port vents
all new accessories and pulleys
UMI k member and LCA’s
KOOKS 1 7/8 ceramic coated LT headers W/ off road Y
RXT clutch for 1k hp.
New plugs and MSD wires

I’ve checked the grounds in the back of the motor... they’re both on tight... (I have the two on the DS on one bolt) my tuner has the car now and is scratching his head and says the car should be running...
it sounds like the car isn’t getting enough fuel... my tuner said it read on the comp that it was getting more than enough... it fires... and I can keep it running if I feather the throttle... but won’t idle. It dies as soon as I take my foot off the gas. I got it stay on by screwing the little screw on the TB all the way down and backing it out 1/4 turn (the screw for the throttle position) after it ran for about 15 secs I touched the throttle to rev it a little, and it shot into HIGH revs on its own... then died. When it starts It sounds like (don’t judge me lol) “brum brum brum woooooooo” the wooo was it sounding like it’s exhaling and weezing at the same time lol...
it’s got fuel, air and spark... and the tuner said the tune is solid... but it won’t run. (Best guy in town when it comes to tuning LS motors for sure) so I know it’s not him... I’m just missing something. The vacuum hose for the break booster is connected in the back... the vacuum line that attaches to the back of the intake (under the booster line) is attached, the map sensor is giving good readings and it’s not throwing any codes. Let the LS Gurus dissect this in 2.3 secs and lmk what I missed lol

 

Did you check pushrod length? Not saying that is your running issues but the PRC aftermarket heads usually take longer pushrods than the standard 7.4 inch. My PRC 225 heads with Morel drop in lifters measured out to 7.525 length.

EDIT to add: I see you bought the engine already running and are just swapping engines out?

 

I did not check the length smh... I thought they would be the same length... ty for your input... and yes the engine was removed from my buddy’s T/A for an LQ9 and it only had 64k mi on it... I purchased it and pulled the running LS1 out of my car and swapped them out. If they’re too short it wouldn’t run at all? Cause I got it run at one point using the throttle screw thing...

 

If it is not getting fuel the obvious culprit is the fuel pump. Should be 58 psi at the rail.

If you ditched the maf and are running speed density, in the maf curve, lowest cell, key in 10 g/sec so you can get fuel until the maf fails.

In my experience on my own ****, if I can keep it running with pedal but not idle, but nothing is mechanically wrong, it is rich down low. There are lots of reasons that can be possible. Especially with a larger cam, if the O2s are reading stoich, it is rich. If it has bigger injectors check the non fuel mg in the transient area and drop it to .010.

Vacuum leak at the injector o rings is possible. Or at the pvc hosing, which is typically rotted out on these cars

 

it was the pushrods, half the valves weren’t opening. Car runs strong now.... BUUUUUUT the valve train is noisy as all hell. The motor sat in my garage for about 5 years waiting on funds to finally pull the trigger on the swap... without an oil pan on it... so no oil in the motor. Not taking this into account, I never though I’d have to change the lifters on a 64k mi motor. But without them sitting in oil... (it didn’t even cross my mind) now my tuner thinks they may have decompressed. And that’s causing the loud valve train.... looks like I’ll be tearing into it again. :/

 

Yeah 7.4 seemed short for PRC aftermarket heads. What was your final PR length after measuring?
Sucks about the drivetrain noise what lifter is installed... LS7's... are you seeing oil to all the rockers?