Fuel System
The fuel system consists of a fuel tank, a fuel feed pump, fuel lines, in-line fuel pump, filter, and a line pressure regulator. Fuel is supplied to each injector at a constant pressure. Only fuel injection duration is varied (to meet changing engine requirements).
The fuel feed pump is an electrically operated vane pump. The pump is integral with main fuel pump. Fuel is strained through a mesh screen before entering fuel pump. There is a check valve on outlet side of pump to prevent fuel supply from draining back into tank.
The in-tank fuel pump assembly is comprised of a main fuel pump, a pressurized container and a fuel feed pump. See Fig 1 .
The fuel feed pump supplies fuel from the tank to a pressurized container. The main, electrically-driven rotary pump draws pressurized fuel from the container and delivers it to the fuel injection manifold. Because the main pump always draws pressurized fuel, air is unable to enter fuel system. The fuel filter is attached to a bracket located underneath the vehicle.
The pump is equipped with a check valve to prevent back flow. Both types off main pumps also have an overpressure relief valve which opens if fuel system becomes clogged and pressure rises too high.