I have a '94 Sierra with a 350. I have no power to the fuel pump. I checked the fuse on the firewall and there's no power to it. I replaced the ECM in the distributer, the fuel pump relay and still no power. I can hear noise when I hot wire the fuel pump fuse on the firewall, but the engine still dosent run with out pouring gass into the fuel injectors. Is it the switch? I don't know. Any ideas? Thanks, Jim

 

could be any number of things. Is the check engine light on?

 

Since I can't get it running the check engine light is on. But at this point I'm thinking it might be the fuel pump oil pressure switch. Will give that a try and let you know. Thanks

 

Your truck will still run with a fault oil pressure switch. Only diesels WON"T run with a fault pressure switch in my experience.
You need a code reader... There is something telling the fuel pump not to run.