I have a 1994 GMC seirra 1500 with 5500 kms on it. It has sat for 5 years. I took the fuel tank out and drained the old gasoline, changed the fuel filter, and put a new battery and gas in it. The truck turns over but I am not getting fuel to the carburator or the fuel filter. I checked the wires going to the fuel pump and it has only 8.4 volts reading with the ignition on. I cannot hear the fuel pump even turn on when I turn the ignition on. I don't want to replace the fuel pump because I fear that there is not enough voltage to run it properly.