Just a few days ago I ran out of gas. I put gas in and we were on our way. It started just fine for about 4 days, then it decided not to. I hooked a OBD 2 to it and it (fule pump)instantley kicked on (it did not before). You all know that gmc is notrorious for the fuel pumps being so loud you can hear them when you go to start the truck, well now the day after I hooked the OBD 2 to it, again its not working, you cant here the fuel pump kick on. The coder both times had " no codes". Is there anyone that can lead me in the right direction?
If you have no codes on the scanner then the problem is probably in the fuel pump system. Running out of gas can damage the fuel pump but I don't think your pump is bad but you can run some test to determine what the cause is. Have you checked the fuel pump relay? The next time the pump doesn't run check the relay and see it becomes energized. You can hear or feel it click when the ignition key is turned on this should happen. If this checks out good then check for power at the pump with a 12v test lamp or volt meter. If you have power at the pump then the pump is bad and needs to be replaced. If no power then you have a open wire to the pump.