Well, I tried and tried to start it, but it would just backfire. After going round and round with PSI, I decided to use the original harness, which is what I should have done in the first place.
Since the harness is from an H2 Hummer, the ECM needed to be mounted in the engine bay. So I bent up a new one to sit on the driver’s inner fender:
I took pics of the wiring I was extending so I wouldn’t screw it up:
I then extended the wiring for the fuses into the tub and mounted it above the throttle pedal:
I was ready to start it, but I read I should clean the injectors, so I did. This is what came out of the fuel rail when I took it apart. And it STUNK. I still don’t know what it was:
Put it back together and it fired right off! I was pumped.
Here is the ECM mount in the bay: