Trouble with 3500 flatbed chevy new fuel pump

I just replaced fuel pump. Started amd ran great .after it warmed up would not crank for nothing .. only thing is the fuel line connectors that connects to top of fuel pump .we had to cut behind the connectot and put it on with a clamp.there is 2 plugins but i only have a harmess for the 4 wire one .is this gonna cause the fuel pump to loose prime or all of a sudden die and not crank agaian until it may crank and it may not.any feedback?