So here it is, I have an LT1 with LT4 heads/Intake and a comp cam with a LS computer from a 2003 Vette and Coilpacks. I am having several issues:

1. I cant seem to license the 03 vette pcm with HP tuners for some reason even though stating unlocked? Is there a way to know if a 99 PCM will take the harness from the 03?

2. Ive been reading alot about the codes ive had come up, Crank Relearn? CASE relearn? Anyone have experience with this or tuning in general for the LS coilpack conversion? The car just doesnt seem to want to run well AT ALL!

 

The 24x conversion uses the LS1 PCM from 01-02 F-bodies. Not sure, but I believe it would be different than a 03 LS computer from a Vette and may be the cause of some of your issues. This is a guess.

 

The '03 Vette is Drive by Wire, your LT1 isn't, right? It is not going to run well. Will have bogus codes, likely idle & throttle response issues.
Didn't use an F body vin in it, did you? Or flash a '99 box with the Vette cal? Hpt won't likely allow you to register either situation.

 

Was the 411 PCM used in 01-02 Fbodies? I always assumed they were all truck/van PCMs. Due to the firing order. I could be remembering wrong though.

Edit: I see a second thread you had made on this issue, more details are needed.

 

When I did my first ls swap into my 97 I used a PCM from a van and it would not fire the car, had to swap over to a new 411 PCM with a 02 camaro file in it.

I never tried that PCM on my 24x swap but I always suggest a f-body 411 PCM and that thinking fired off my 94 with no issue, I would try to swap the PCM and and go from there.

 

The 411 PCM was used in both LS and gen 1 Vortec apps. You can't change the order itself in the computer so GM just pinned the harnesses differently for cylinders 4/7 and 2/3. It's only possible because the PCM will allow you reassign cylinders to different banks so fueling doesn't get screwed up in closed loop.

 

An EFI Connection 24x LT1 conversion can use any Gen III LS-Series PCM (1997-2006) or any aftermarket ECU designed to work with a Gen III LS-Series engine.