89 f150 fuel pump not working

Hey guys, i got a 89 f150 with the 300 I6 and dual fuel tanks. There is a feeder pump in each tank and one on the rail. The rail high pessure pump has failed on 2 new pumps with less than 5 minutes of being cranked. I can run a hot wire from battery to the pump and it doesnt even work. Both of the newpumps sounded louder than the original one and i just assumed they were different. Could this have been a sign of imminant failure? Im thinking it is a electrical problem shorting the pumps out but not sure. With a multimeter, i get 11.5 volts at the pump for a split second then dwindles to nothing. Any advice before buying a third pump would be appreciated. Thanks joel.