MnTom

I don't have a VP, but I do have a question. Since the VP does have an overflow valve, if it failed (lost spring tension or leaked through) would that 'starve' the VP? What I am wondering is that since the fuel like any other fluid will take the path of least resistance, the fuel would go back to the tank instead of going where it was needed in the pump. This would have the same effect as the LP failing wouldn't it? I have been thinking about this for a while and have not been able to reach my own conclusion. Any ideas or thoughts?
Tom

rockwithjason

Well, common sense would say that a whole lot of fuel would bypass to the tank and fuel pressure would drop in return. I would think that you would starve the pump or at least limit the fuel supply.

JAFAW

The fuel flows in under the computer to a internal supply pump ( Which makes 30 to 350psi depending on rpms) then to the rotor head or advance piston then what is not sent to the injectors is used for cooling and returned. Even when the pump is not firing (like coasting down) fuel is pushed thru to cool the pump. that is why the truck runs for a short time after the transfer pump fails