need help getting my LS swap running

[cr92]

hey all, I've got a 1987 chevy r10 truck i recently put a 4.8/4l60e in.

motors in, i took all the wiring from the donor truck (2000 silverado) and put it in my 87. i then chopped off the engine harness for the 4.3 TBI that was originally in it and plugged that back in the firewall with a foot of slack for joining wires together.

anyway i found online that i needed the red wire, pink wire, and grey wire from the 87 harness to connect to the same colors on the 4.8 vortec fusebox harness. i connected them, along with the starter wire(purple) wedged under the fuse box against the 4.8 purple wire. when i turn the key the engine cranks over but won't start. i checked the fuel pump relay and i can't see any power on any terminal?

i manually bypassed that by running 12v to fuel pump and tried starting the truck like that but still nothing.

i guess the easiest way to describe what i have is the original 4.3tbi harness is cut off 1 foot from firewall plug in, the fuse box, computer and engine wire harness from 4.8 are all connected and untouched. then i have the wiring block c2 cut off the 4.8 truck and bolted to bottom of fuse box (only 2 wires joined to this though (the red 12v + wire for ignition ran to the red wire on firewall, the pink 12v+ for ignition hot in run/start ran to pink on firewall)

then i have connector c3 cut off the 4.8 and have the grey wire attached to fuel pump wire but cannot get any power to come off of the grey wire(no power at any of the relay terminals either) so i cannot get the fuel pump to kick in while key is in forward position... like i said i tried bypassing that by running 12v to the fuel pump and it will stay turned on as long as i hold it there but the truck won't start.

anyone have any ideas on how to go about getting the truck running? first time doing anything like this I'm a bit stumped.