Have replaced fuel relay and tested pump but still getting no power to pump 1990 accord

have you checked all fuses and the main 12 volt relay under the driver side dash?

At this site I show the relay can be had for $25.00
BECK/ARNLEY Part # 2030228 Main Relay( fuel pump) $24.79

A relay has two sides to it-the power feed and the line to the pump is the one side of the relay. The other side is the "coil side"-what makes the relay switch on and pass power from the power feed to the fuel pump wire. The coil side has a signal from one source-your computer-and the other coil side wire goes to ground, usually. When the coil side is activated by a signal from computer, the other side of relay closes contacts so power is passed to the fuel pump.
Don't know if a switch will work there, but you could try it. You may need to look at a wiring diagram. If the coil doesn't get a signal from the computer, there may be other problems, like in your wiring or in the computer.

Voltage drop test the electrical circuit , do know how to do automotive electrical testing . Lose connection , resistance in the circuit , lose ground Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia Testing Electric Fuel Pump Problems with Voltage Drop Test

I'd have to test when problem is ongoing. When you first turn on key, no crank, you should hear the pump run for a few seconds then stop. For initial prime, the computer doesn't need rpm signal. Engine cranking, the computer needs to see rpm signal or it won't ground the fuel pump relay. W/o rpm signal, no spark at the plugs and no fuel injector pulse. I know your talking about fuel, but, when problem is ongoing, check spark and fuel injector pulse, engine cranking.
Intermittent problems are a pain, have to test when problem is ongoing.

Not guessing as to what the problem is , testing for voltage drop problems with a volt meter . posted a video on youtube yesterday . If your still looking for guesses forget it , no one on here could say for sure without testing the circuit an hooking up a scan tool to see if PCM is energizing the relay . Do yourself a favor an take it to a qualified repair shop . Fuel Pump Electrical Circuits Description and Operation If you can't learn how to test from this guy , better take to a repair shop .

It's going to be your main relay, located under the dash on the drives side, turn key on and off, you will he a clicking sound, that the main relay control your power to you computer also.

yes have the computer repaired and this should fix the problem. these cars are known for have the computers go bad.

other than the timing belt being broken, it sounds like the crank sensor in the distributor. get a used distributor. but first pop cap off and see if it is turning with engine.

check the fuse .if the fuel pump was bad you blew the fuse . there is a inertia switch in the trunk or under the dash you could check . push the red button to reset relay should be under the hood in the fuse box check your book if you have one.