The main relay switches the pump on & off, but the ECU tells the main relay what to do.

You can check for power back at the fuel pump wires. If there's power back there, then the pump is bad. But it's a new pump so I bet you'll find there's no power back there.

Probably I would start by checking power & ground at the main relay. I don't have a circuit drawing for 93 but that would be real good for you to have. What's your electrical troubleshooting experience/skills?