3500 fuel problems

alsride · November 20, 2003

I have a 1996 3500 with a 6.5 turbo diesel. It is a flatbed with a dual fuel tank setup. Each tank has a pump. The rear tank pumps into the front tank and the front tank pumps up to the motor. I am pretty sure it is a factory setup, both tanks drain equally. I can drive the truck all day sometimes with out a problem, but most of the time I will be driving and the thing will stall out. I know it's a fuel supply problem. I turn the key on and I can hear the fuel pump come and about a second later it shuts off once it builds up pressure. The truck will immediately start up and run until it stalls out. It already has a new fuel pump and it's not sucking air. I already replaced fuel filter and still has problem. I figure it is either a problem with the fuel pump relay(highly doubt with this case) or a tempermental pressure regulator. I did not find a return fuel line so I supposed that the computer monitors fuel system pressure and turns on pump when it needs pressure. I figure if the pressure sensor isn't working right it doesn't turn the pump on, until I turn the key on again and it turns on pump because of default. If anyone has any knowledge or info on this problem it would be greatly appreciated. Thanks.