Originally Posted by
blindsquirrel
The outer metal case of the PCM, any part of it that's metal is electrically connected inside to the pins that get grounded through the harness, so grounding the case directly bypasses all the grounds it'd normally get.
Turn the key to RUN, then take a wire, any old wire, stripped bare on each end, touch one end to the PCM case and one end to something that's a good ground - alternator bracket, front strut mounting nut/stud, battery negative, whatever. If the jumper wire does indeed supply a ground that's missing you will hear relays click and the fuel pump run and fuel squirting through the rails when the PCM powers up. If the ground wire does nothing, you have some other problem and can stop thinking about missing grounds, and you didn't have to crawl under the car or look in the manual for ground points or anything.