Fuel Pressure Regulator Assembly

WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

The fuel pressure regulator is a part of the fuel pump fuel reservoir pump fuel strainer orifice. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. Fuel pressure is controlled by a pressure balance across the regulator. The fuel system pressure is constant and is no longer a function of engine load or manifold vacuum. Excess fuel from the fuel pressure regulator is directed to a siphon jet pump located in the fuel pump fuel reservoir pump fuel strainer orifice. The pressurized fuel creates a venturi action inside the siphon jet pump. The venturi action causes the fuel to be drawn out of the fuel tank and into the fuel pump module reservoir.

An over pressure relief valve, located in the discharge outlet of the fuel pressure regulator, will open if the fuel system pressure becomes too high. This is a safety device to prevent fuel system damage.