
Originally Posted by
Mickeymotormount
The PCM provides power to the fuel pump relay, not a ground. Your original relay can be used but the actuating power must come from the new PCM, not the old one. Should be as simple as undoing the present power wire to the relay and using the Dark green/white wire from the new PCM to power up the relay.
Once the new wire is used to power the relay, it will, in essence, be grounded through the relay actuating coil.
BTW, welcome to the site. Keep us up to date with your swap. Pics would be cool too as we all like them around here.