F 350 4WD Pickup V8-351 5.8L VIN H EFI (1997)
Fuel Pressure Regulator: Description and Operation
The fuel pressure regulator is attached to the fuel injection supply manifold downstream of the fuel injectors. It regulates the fuel pressure supplied to the
fuel injectors. The fuel pressure regulator is a diaphragm-operated relief valve in which one side of the diaphragm senses fuel pressure and the other side
is subjected to intake manifold vacuum. The nominal fuel pressure is established by a spring preload applied to the diaphragm. Balancing one side of the
diaphragm with manifold pressure maintains a constant fuel pressure drop across the fuel injectors. Fuel in excess of that used by the engine is bypassed
through the fuel pressure regulator and returns to the fuel tank.
