2003 Chevy S-10 Fuel pump

Hi, I am having nightmares with my truck, initially the fuel pump went out and I ordered a rebuild kit with new pump motor and replaced it. I then drove the truck to town to get plugs/wires and also let the truck idle at the store and in the driveway for well over two hours. Ishut it off went in and ate lunch and when i went to start the truck again it wouldnt start. After a little investigating I found the ecmb fuse (20AMP) to be blown, I replaced it it blew again, I replaced the relay and it blew again, I unplugged the wires from pump and then I even tried unplugging the relay itself it still blows.I finally replaced the computer and it still blows the computer please help Thanks Tony