I'm a little confused, you've tested the wiring to the ckp sensor which is good and tested at the ecu plug which is also good so why are you opting to replace the loom.

Have you unplugged the ecu connector and scoped the ckp sensor at the plug pins. Its an inductive sensor isn't it so should still see a pattern with the ecu disconnected unless it wont crank over with ecu unplugged.