how to cure no injector pulse on a 1996 Holden VS Commodore V6 Ecotec motor

Cahanged engines. swapped VS V6 with a VS V6, Put original engine wiring loom on replacement engine, Since then, have changed CAS, Cam hall effect sensor, chipset in pcm, key remote head, tried to follow thick orange wire from power side of EFI f/ pump relay. Followed it to the 6 pin connector on the end of the engine loom. wire then swaps to a thinner purple wire which follows along the R/H injector bank and goes under the alternator, eventually running down behind the power steering pulley ending up as the power wire for the oil pressure switch.Can't work out how this could haqppen when we were replacing one motor for the same model and type of engine....