i replaced the fuel pump now it wont start unless i put gas in engine then it run

Did you say Carb? What Carb? Your 1997 Chevrolet truck receives fuel via a fuel injection system, not a carburetor. Either way, if you have no fuel delivery to the engine, check for base fuel pressure with a pressure tester at the fuel rail. Also check to make sure there are no anti-theft system activations stopping fuel supply. If you are unfamiliar with fuel pressure testing, seek professional guidance, as fuel testing can be dangerous.