94 Rodeo Engine wiring help

4 years and counting...my hubby replaced the engine of my 94 isuzu rodeo with a used one. ( 4 cyl, 2.6 ). However he has one wiring harness that doesn't connect to anything...from fuse box to engine with these wires ...2 black/red, 2 black/green 2 black grounds... where do they attach to the engine? I would really like to have my isuzu running again. Suggestions would be appreciated. We have a repair manuel but it doesn't explain wiring is there other manuels available with more extensive engine wiring replacement/repair?

The engine has power but no fuel...lights & all work he knows it's electrical but hasn't been able to find the problem. Isuzu seems to have lots of electrical/wiring problems.

Thanks,
disheartened wife