2003 chevy 2500 6.0 replaced the fuel pump and it ran long enough to pull it in the shop now it wont run all I have at the furl pump is 5 volts replaced the relay and still no fuel pump can anyone think of what else tell the pump to come on.

Check the fuel pressure at the engine and plugs for spark (ignition module).

fuel pump fuse fuel pump relay ignition switch

Check electical connections it might be the output current touching to others input voltage.

PCM

check fuel pump pressure....GM is known to have faulty ones that work after started and will run but wont send enough on cold srarts...Good luck...Lee

a code would not come up unless check engine light is on is the truck getting fuel at the injecters check the shreader valve if it is than check spark.

yes it could be the fuel pump. my chevy truck was doing something similar, would start unless i parked on an uphill grade. when you turn the key through run to the start position the fuel system pressurizes. if your fuel pump is weak it can't draw hard enough to pull the fuel up. as long as the vehicle is running the fuel system is primed, but when you shut it off it runs back down to the tank. that's the way it's designed and it's not normally a problem, but if your fuel pump is getting tired it can't pull it up any more. just a tip, if you live in a hot climate, especially in the summer, your fuel pump will live longer if you keep it over a quarter tank. the fuel pump is really just a little electric motor that incidentally pumps fuel and generates a lot of heat. the fuel in the tank helps soak up the heat and let your fuel pump live longer. hope that helps

if it wont start, then chances are that you have seized the fuel pump, due to running it below 1/8th of a tank alot. this is common on chevy 1500 series and 2500 series gasoline engines

You will need to get up there Right above the Throttle Body and hold a Good Maglight or LED Flashlight above the TBI and have Someone Crank it Over. You will see the Spray inside the Bowls if it is Getting to the TBI.

there is a technical service bulletin to relocate the fuel pump on this vehicle when the transfer pump needs replaced. there is the possibility the transfer pump is going bad on the 2003 now...its not good to run them low or out of fuel