Where is the fuel pump relay on '95 C1500?

If the pump comes on...you should have some type of pressure and if it was a fuel issue it should at least started with starting fluid.

Did you check fuel pump pressure an electrical circuit before replacing the pump ? Or did you just guess ,fuel pump ? Does it have spark ? needs spark too .
https://www.youtube.com/watch?v=ZgNY3ZpjSsU&t=450s

Watch this video .

This truck uses a high pressure fuel system, key must be on for the electric fuel pump, which is in the tank, to work. Fuel pump senses when pressure drops, so that it will shut off if there is full pressure, and engine not running. If there is lower pressure, such as a broken line, it will continue to pump, if the engine is running. If you're asking if it has a safety feature shutting it off in an accident, no it does not, except if the engine shuts off due to the accident, fuel pump will not work, unless key is turned off and then back on, and will then work for about 5 seconds and shut off, unless engine is started. If you're asking why the fuel pump doesn't work after an accident, it's most likely damaged, or a wire has been damaged, OR the computer maybe damaged (therefore telling it to turn on/off when key is on and engine running with key on and pressure is low, or at the right level to run the engine. Again, if you turn the key on and do not start the engine, fuel pump will work briefly for about 5 seconds to bring pressure up to where it can be started, then the fuel pump will work again when the engine is started (so the fuel pump isn't running with the engine off for very long.)

No crank and no start are two different things.
For no start, you will have to figure out if it is fuel or ignition related.
You can run a compression test on the cylinders to check the head gasket. Usually a leaking head gasket will not cause it to not start all at once.
Hondas are known for fuel pump relay problems. Do you know for a fact the injectors have fuel pressure ?

Have you ever change the fuel filter
Even the air filter.

sparks, fuel pump, ecm, fuses relays.

running the fault codes at an auto spares shop will give you the codes that are causing the problem
if you run low on fuel it could cause a pump problem but as you drove it home after the problem , I doubt i f it is the pump

A bad fuel pump will not keep the engine from turning over. I would first test your battery and make sure your connections are clean. If that check out I would check your starter and starter relay.

It sounds like an air lock or a fuel pump issue. firstly get the filter changed and bled through this might help. if the problem persists check the pump.

Regards

Dan

most likely on the firewall comes out of fuel pump relay harness only has power while running or for two seconds when ign key is first turned on