The red plug is the DLC. Don't worry, it shouldn't be plugged into anything.
Why did you remove the wire harness to get things painted?
Are there any codes flashing with the FI light on the dash? if so, what's the sequence of short/long flashes? Since the entire wire harness was removed, you could have a **** load of possible issues. Best to start with the most obvious.
Lift up the fuel tank and disconnect the harness. Hook up a volt meter and check for battery voltage when you turn the ignition to the on position. You should see a spike in voltage for 2-4 seconds before it drops to little to no voltage. If there is voltage present, the fuel pump is bad. If there is no voltage, time for some deeper troubleshooting.
Is the ECM plugged in fully, and the connectors in the correct location?
Is your BAS plugged in and mounted correctly?
Is your engine stop circuit ok? Switch plugged in with no damage and the relay is good?
Is your fuel pump relay working? Can you hear it click when turning the ignition on?
Is the sub fuse for the FI system good?
It will take a while to look through all of that, but the problem will be somewhere within it all.