Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator:

EARLY MODEL VEHICLES
The mechanical fuel pressure regulator is used to maintain a constant pressure differential at the fuel injector tip of 14.5 psi. The pressure regulator uses a spring loaded diaphragm to control the fuel return port in order to maintain constant pressure. Pressurized fuel is delivered to the fuel injector and the pressure regulator. When fuel pressure acting on the regulator diaphragm exceeds 14.5 psi, the regulator spring is compressed and the fuel return port is opened. When fuel pressure drops below 14.5 psi, spring tension causes the diaphragm to block the fuel return port. The diaphragm and spring move constantly between the open and closed positions in order to maintain constant fuel pressure at the injector tip.

LATE MODEL VEHICLES
The mechanical fuel pressure regulator is used to maintain a constant pressure differential at the fuel injector tip of 265 kPa (39 psi). The pressure regulator uses a spring loaded diaphragm to control the fuel return port in order to maintain constant pressure. Pressurized fuel is delivered to the fuel injector and the pressure regulator. When fuel pressure acting on the regulator diaphragm exceeds 265 kPa (39 psi), the regulator spring is compressed and the fuel return port is opened. When fuel pressure drops below 265 kPa (39 psi), spring tension causes the diaphragm to block the fuel return port. The diaphragm and spring move constantly between the open and closed positions in order to maintain constant fuel pressure at the injector tip.