Fuel Pressure Regulator

The fuel pressure regulator is a diaphragm-operated pressure relief valve consisting of a diaphragm (3), a spring (1), and a valve (4). The fuel pressure regulator keeps the fuel pressure applied to the fuel injector at a pressure 290 kPa (41 psi) greater than the pressure in the intake manifold.

The pressure (5) applied to chamber A (2) of the fuel pressure regulator is the intake manifold pressure (8). The pressure applied to chamber B (7) of the fuel pressure regulator is fuel pressure. When the fuel pressure rises more than 290 kPa (41 psi) higher than the intake manifold pressure, the fuel pushes a valve in the regulator open and excess fuel (6) returns to the fuel tank via the fuel return pipe.