Fuel Pressure Regulator: Description and Operation

Fig. 8 Fuel pressure regulator:

The fuel pressure regulator, Fig. 8, is located on the fuel supply manifold and regulates fuel pressure supplied to the injectors. One side of the diaphragm in the regulator senses fuel pressure, while intake manifold pressure is applied to the other side. Nominal fuel pressure is established by spring tension applied to the diaphragm. A constant fuel pressure drop across the injectors is maintained by balancing one side of the diaphragm with manifold pressure. Excess fuel is bypassed through the regulator and returned to the fuel tank.