1999 5.3 cranks but has no spark

I need some help from anyone who knows these engines. From what I can see everything is hooked up correctly but obviously something is wrong…. I have spent 2 days trying but can’t figure it out.

Modified factory wiring harness and computer

Generic wiring harness and fuse box

Th400 transmission pre computer

Absolutely no factory wiring left to reference.

How are the ground wires? Is the vats turned off in the computer?

I have 3 grounds from the harness grounded to the block. 2 of those are also grounded to the firewall and the other to the frame. I also have the battery grounded to the block and frame plus 2 more grounded from the engine to the block. I have tested ground in both coil grounds and they are good. As far as the computer it was sent in and modified so should be all set but I don’t know how to verify this. I’m going to pull the crank sensor this morning to test but otherwise I am baffled. This thing should have fired up 2 days ago…. It’s getting frustrating to say the least.
Also, I am not showing any codes but all I have is a basic code reader

Did you ever solve this? If it’s a modified factory harness then something is wired wrong. Had same issue, bought a GOOD standalone harness and motor fired right up.

No, I have not been able to get it started. That was an idea that I was thinking of. Just to rule out an issue with the wiring because the wiring was done about six years ago. I purchased this build from another person who kind of gave up. The concept for this wheeler is fantastic, but since I bought it mid build, I really don’t have a lot of good information on some of the things that were purchased. Back when he first started this bill it was more of a thing to get the original wiring harness reworked now it’s just easier and cheaper to buy a new wiring harness. I think that’s the direction I’m going to go in and hope it starts up. I will post an update once I have the new wiring harness.