I screwed up big time....

[PowerDubs_imp]

Dubs you may have already checked this but do you have 12 volts on all four black/white wires on the fuel injectors?
They are fed from the +12 volt " fuel cut" relay.
just unclip one and check for 12 volts on the black/white wire with ignition and killswitch on.

They get pulled to ground by the ecu and have back-emf diode protection in the ecu circuit across the transistors/fet's.
If the ignition switch was off the ecu had no power and was only connected to ground and the controlling injector circuits should not be damaged because they were not activated.

Good job with the starter fluid, divides the problem in two parts right there, golden.

Do you have a circuit diagram to work things out?

Confirmed yes, on one of them. Any need to do all 4?

I'd start checking if voltage arrives at the fuel pump with/without the killswitch (or just have someone listen: contact on and kill switch on/off and you can hear the fuelpump working for a second when you swith to "on").

I wouldn't be surprised if there is extra protecction not to allow a melting wire inside the fuel tank, so I'd check that circuit first.

The harness shouldn't be the weakest point on any installation: no matter what you connect it to. Fuses (or some components acting as fuses) are there to prevent wires to get too hot and avoid fires. So I don't think you'll find a melted wire. But I've been wrong before...

Any know off the top of their head which wire at the connector where the fuel pump plugs in at the side of the airbox?

I have already gouged my hand getting the tank disconnect off- so would rather not try to test at the tank itself.