I can't understand the connection/problem switching like this, as it runs the same wires from each ecu for the features listed.
Keeping the correct 2wd ecu on, where you get spark but no fuel, power the pump manually by bridging 30 and 87 of the relay holder with a bit of wire does it now start and run ?, if yes then good.
The ecu outputs to relays one of which is soley for the fuel pump, will have a black/red wire coming from it, this is the feed to the pump(via fuel cut off if fitted ?), this relay is fed by the main power relay which applies the live to the fuel rail amongst other things, so we know this relay is outputting, so missing the link between this and the fuel pump relay.
They can suffer terribly from bad connections due to age so have a good wiggle of the loom as well, the relays mentioned are on the loom itself, some just bypass the ecu trigger and run direct from ignition keeping the cut off in line.
tabetha