Gen V L83 swap question, start and stall

[LH Lead-Foot]

I think that I would talking to Speartech, if they reprogrammed your PCM. My GM eSI (Electronic Service Information) only goes to 2004. My guess is that the pass-lock was not disabled. With an actual schematic or year of donor vehicle, I would be completely in the dark. It is called removing VATs.
As for disconnecting the negative battery cable and runs fine, no clue as everything in the donor vehicle to the PCM uses EEPROMS which do not change or lose memory by disconnecting power. So?
I ran my 2003 5.3L Tahoe engine on a stand for days cleaning injectors, compression test, etc. Just powered up the BCM, placed it on the class 2 network and bypassed VATs with an 8k ohm resistor at the BCM VATS input doing a relearn with my TECH-II
ASE Master Tech since 78 - Retired