Just curious before I pull my fuel pump (which is consistently showing low pressure - 40-45 psi at test port at engine). Would the pump work at all if the voltage was low to the pump? I'm thinking what if I I had only 5-7 Volts instead of 12 at the grey wire? There's probably not a convenient disconnect to test this out? Also, will probably order the MU1748 AC Delco fuel pump/sending unit. Does it come with everything you need?