Fuel Pressure Regulator

The fuel pressure regulator is a diaphragm operated relief valve. The fuel pump pressure is on one side of the regulator, and the regulator spring pressure and the intake manifold vacuum are on the other side. The function of the fuel pressure regulator is to maintain a constant fuel pressure under all of the operating conditions. The pressure regulator DOES NOT compensate for the engine load by increasing the fuel pressure as the engine intake manifold vacuum drops. The vent on the fuel pressure regulator is connected to the bottom of the throttle body for an atmospheric vent only. The fuel pressure regulator is mounted on the fuel rail.

With the engine running at idle, the system fuel pressure at the pressure test connection should be between 275-313 kPa (40-46 psi). With the system pressurized and the pump OFF the pressure should stabilize and hold between 240-275 kPa (35-40 psi). If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.