Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator:

PURPOSE
Regulates fuel pressure supplied to the fuel injectors.

CONSTRUCTION
The regulator is a diaphragm operated relief valve.

OPERATION
One side of the diagphram senses fuel pressure and the other side is connected to the intake manifold vacuum.

Fuel Pressure Control
Fuel Pressure is established by a spring preload applied to the diaphragm. Balancing one side of the diaphragm with manifold vacuum maintains a constant fuel pressure drop across the injectors.

Fuel pressure is high when engine vacuum is low. Excess fuel is bypassed through the fuel pressure regulator and returned through the fuel return line to the fuel tank.