Ok, I'm trying to understand how the fuel system works, especially the low pressure side.
So the pump draws from the tank, through the fuel filter, and into the IP.
The fuel filter housing, IP, and injectors are each connected to the return line. The return line returns back to the tank.
Somehow 3-5 PSI is maintained in the system, or so I've read.
Yet if there is no restriction in the return line, then how is the pressure maintained, eg between fuel filter and IP? In particular, as I understand it, the pressure should be maintained even with the engine off, when the low-pressure pump is not active.
Ok, I believe that the IP and injectors should require high pressures for fuel to get from the primary path into the return line. But what about the line between the fuel filter housing and the number #1 injector return cap? What prevents pressure from bleeding off there?
So the pump draws from the tank, through the fuel filter, and into the IP.
The fuel filter housing, IP, and injectors are each connected to the return line. The return line returns back to the tank.
Somehow 3-5 PSI is maintained in the system, or so I've read.
Yet if there is no restriction in the return line, then how is the pressure maintained, eg between fuel filter and IP? In particular, as I understand it, the pressure should be maintained even with the engine off, when the low-pressure pump is not active.
Ok, I believe that the IP and injectors should require high pressures for fuel to get from the primary path into the return line. But what about the line between the fuel filter housing and the number #1 injector return cap? What prevents pressure from bleeding off there?