Given it's a del sol, one of the leakiest cars Honda ever made since the 70's, it's probably a whole lot of corrosion.
You'd want to check ALL the wires involved with the main relay. First you'll want to feed the pump +12vdc directly to possibly rule it out. The ECU is the only thing that can tell it to run the pump via one relay inside it. That's the main wire to check, rather both of them. A7 and A8 can both have green/yellow wires feeding the fuel pump relay inside the main relay.
If the pump isn't getting power, and the green/yel wires on the main relay aren't grounded, it's the ecu wires. Otherwise fuse #18 should be what feeds the internal relay's coil with +12vdc, blue/white wire, at least on a Civic.
Knowing my luck diagnosing shit, it will be something completely off the wall like a clogged pump because you run your tank dry and it (pump and/or filter) is filled with shit.