Popping INJ fuses on Beretta LS swap. Both banks acting identical.

Been a while...been so busy I only pop in when I need help. :(

I have a 4.8 I'm putting in a Beretta (with a 5spd and Ford 8.8 to make it RWD). haha
https://www.youtube.com/watch?v=2JnU-ZbfYH4

I got the 2000 4.8 out of a running truck with the whole harness and fuse block intact. I wired it to test run on my stand after swapping on car intake and pan. Everything is set up just like LT1swap.com says. Power out and back from key (rocker) switch and a momentary starter switch and the PCM pink from the C100 connector run to switched 12v.

With everything plugged in it pops both INJ A and INJ B fuses immediately with the key on.
Unplug all the injectors and coils and it doesn't blow.
Plug all the injectors in: fine
Plug in the coil harnesses (without individual coils plugged in): fine
Plug in any single coil on either side: fine
Plug in 2 coils on either bank: blown fuse

Any ideas? This one has me stumped.

BTW, I'm getting about 1200ohms from the circuit at the fuse location to ground. Same test on my 2001 truck in the driveway with 8.1 is 1600ohms. Is that a clue?

Thank you in advance.

https://i.imgur.com/QZyG9Zg.jpg

That's a strange one. Is there a possibility you have a wire making contact with ground when all the coils are connected?

Strange indeed, However a blow fuse is a short. Don't over think it, find the short.

I'm an idiot. Keep it simple stupid. I'll share my stupidity in case anyone else finds this in a search...

Flashed the factory truck tune back to the PCM to make sure there wasn't something off with my modified one. Then, as I hooked everything back up (PCM and fuse block stacked on top of the battery) I noticed I had the damn terminals backwards! FYI: red goes to B+ and black to B- haha

Lol, it happens. My new ecm/pcm programming station has built in protection just for that and many more protection circuits. As much as we all know, we get in a hurry sometimes the closer we are to the finish :)

Its a fine line between clever and stupid and I cross that line way too often. Sounds like you did too but I bet it'll never happen again this way.

Rick