Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator:

PURPOSE
The fuel pressure regulator is used to maintain a constant pressure of 4 psi in the fuel supply system.

OPERATION
The pressure regulator uses a vacuum assisted spring loaded diaphragm to control the fuel return port in order to maintain constant pressure.

Pressurized fuel is delivered to the fuel rail and then flows through the injectors or the pressure regulator.
- When fuel pressure acting on the regulator diaphragm exceeds 48 psi, the regulator spring is compressed and the fuel return port is opened.
- When fuel pressure drops below 48 psi, spring tension causes the diaphragm to block the fuel return port.

As manifold vacuum increases during deceleration, less pressure is needed to supply the same amount of fuel into the air flow. In order to fine tune the fuel pressure under all operating conditions, the vacuum assists in opening the fuel port during high vacuum conditions.