Ls1 wont rev over 4000 rpms and die's at random
 

Just finished a Ls1 swap in my 91 Camaro. Donnor car was a good running 2000 camaro. Drove the car to work yesterday and I noticed that it was missing under heavy load. Figured it was plugs so I bought some TR55's on the way home. Today I got in it to take it to the store (Knowing that the car might still be missing, haven't installed the new plugs yet)and Now it just falls on its face when you floor it. It acts like a DBW car when you hit the speed limiter, It doesnt feel like it is missing it just wont gain any speed. It isn't speed related because you can do it in 1st gear or OD. The car would start right back up but would fall back on its face quickly if you labored the engine at all. I ran a log on it to see if anything crazy jumped out at me but I am still pretty green to the tuning scene so the problem could be staring me in the face but i don't see it. I did notice looking at the log that it doesn't want to rev over 4000 rpms. Friend of mine thinks it might be the crank or cam sensor but i don't know how to tell (I logged that by the way) Checked fuel pressure with a manual gauge and I have 60psi at idle. My hose isn't long enough to watch it when driving down the road.
I am thinking its fuel related but that is just a guess.

Mods: LS6 intake, LT headers, 3.73, 4000 stall Performabuilt lv2 trans.

@3:11.086 when watching the log file is when the car died going down the road.

Bad knock sensors??

It's fuel. Look at the at the short and long term fuel trims just before it dies. I see more fuel supply issues on transplants than any other issue.

I am going to yank the tank. The sending unit out of the donor car was damaged from the wreck it was in. One of the sliding rods where bent and the other one broke. I was able to straiten one but had to weld the other. I wonder if the flex hose got kinked or something.

I can't tell by that pic if there is a problem there or not.

The rods that the bucket slides on fell out. The lower part of the bucket was just sloshing around in the tank. The rods go threw those springs.

So I replaced the fuel pump and bucket and I am still having the same issue. The car hasn't always done this. The first few drives we took it on it pulled hard to the rev limiter. I also tried flashing the stock tune back in the car but same issue. I am starting to wonder if I have a grounding issue. Today after work I am going to clean all the grounds and see what happens.

Not sure what your fuel system looks like. You say it wasn't doing it the first drives, when it started again was it after enough time the fuel could be too hot?

I had this issue last year at the track, after driving 2 hours in the heat, sitting in the staging lanes, during a pass it would fall on it's face hard at around 4k rpm. If I went down the road and popped the gas cap and topped off the tank it ran fine. At first I thought the fuel level was too low, but it later clicked it was probably more so due to pressure and heat buildup in the tank causing cavitation.

You might try picking up a vented gas cap or drilling a tiny hole on the one you have.

Car has 1/2 tank of fuel. I have tried running without a fuel cap also. I will drive it cold when I get home to see what it does. It seems to be very consistent tho at 4kish rpms

I would also look at the MAF or try unplugging it. If I remember correctly 4000rpm or so is the factory setting for switching to MAF fueling WOT. So if the MAF is junk or has a large piece of trash on it, that could also be the issue.

I lost the damn log file i just recorded.... Anyway I went WOT when the coolant temp was showing about 140* and it does the same thing. If im not mistaken that first log file i posted the MAF was unplugged. I also added another ground from the rear of the head to the body. I am at a loss. I am pretty confident that its loosing fuel pressure. To find out i guess i am going to have to pull the hood and rig my gauge up some how so i can see it. IF it is loosing pressure i guess i could record the voltage at the pump when the problem happens. If the voltage does drop i have a wiring issue. If not... I'm lost.

https://ls1tech.com/forums/pcm-diagnostics-tuning/1732123-looking-ls1-pcm-internal-schematic-p0200-issues-misfires-4-7-a.html#post18333254

I had the same problem.

I have a extra set if coils laying around I will try.

If the car has cat converters and they are clogged that can cause excessive back pressure resulting in the condition you are experiencing.... just a thought I had since it doesn't state what exhaust is run

Disconnect the Maf or turn it off in the tune and see if you have the same problem. As Thunderstruck said the maf controls from 4000 rpms and beyond.

The car is open headers right now. No exhaust. I will pull the MAF again.

So... Funny story. Drove the car to work today hoping that it would just break so i could figure it out. It fell on its face all the way and at lunch when i left to go get something. Got in it to go home and about half way home the upper radiator hose blows. Car never got over 200* but the upper hose wasn't in great shape so it wasn't a huge surprise. Had a friend bring a hose and some coolant and got it going. I pulled the MAF to make it easier to work on the car and just didn't put it back on. The car instantly felt like it had 2X the power. Gave her the skinny pedal and left 2 nice black marks. So ether the coolant got in something or the MAF was the issue. Its odd that i unplugged it before and it didn't help but i guess we will see.

You can't run a car with O2 sensors in closed loop with open headers. That explains a lot of your +20% and +30% fuel trims. Your plugs are probably fouled.

That is also a good point. If I run mine at idle too long with both cutouts open (staging lanes) it will surge and sometimes die. There is about a foot of pipe between each cutout and the collectors.

So that could be the issue with the car stalling out on you, especially if it's mostly occurring when you let off throttle.