i quit getting fuel to the tbi on my 89 blazer 2wd 4.3,the sending unit was bad and i ran it out of gas a few times,so i figured i burned the pump,,,,well i changed it with a new drop in unit { pump,sender etc...},,got everything back together,tried to start it,,,,,no fuel to the motor,,i pulled the filter,turned the key ,,,no fuel ,,,,,........the battery shows 13.3,but the fuel pump plug in shows only 8.4 volts,,,,,,,,,,,,, wtf.......will the pump not run at all,with 8 volts ????????