Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator Assembly:

The Pressure Regulator Assembly is a diaphragm-operated relief valve having fuel pump pressure on one side and regulator spring pressure and intake manifold vacuum on the other. The function of the regulator is to maintain a constant fuel pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops. The pressure regulator is mounted on the rear fuel rail and is serviced as a complete assembly.

If the pressure regulator supplies pressure which is too low (below 284 kPa or 41 psi) poor performance, Code E042 or E044 or detonation could result. If the pressure is too high, rich operation, plug fouling, Code E043 or E045, poor fuel economy, and excessive odor may result.