I have an automatic 2003 silverado 5.3 that stopped running. It had air and spark, but no fuel pressure so i decided to replace the fuel pump. Installed the new pump, but there's still no pressure. The new pump required me to re-wire on a new electrical connector. I believe i did that correctly since the gas gauge works and when i turn the key on, the pump hums. When I have the fuel lines disconnected from the pump and turn the key, the pump hums but nothing comes out at all. The tank is half full.

 

pump may be wired backwards. the big wires to the pump and smaller to the sender... but maybe the pump is spinning backwards?/?

returnless fuel system or does it have a return line to the tank? if it has a return line it will have an external fuel filter. it should be changed when a new pump is installed.
hard to recommend anything on the wiring without knowing the pump you have....any wiring diagrams for the new pump?

 

yeah the pump was wired wrong. The wiring instructions weren't clear about specific year models and there were about 4 possible combinations. I was just confused as to why the pump was turning on and not pumping anything. I think you were right about it spinning backwards. Appreciate it.

 

carter pump? they are confusing....they should provide the diagram for the pump they sell you....instead they list options for a pump from another kit.