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Home >> GMC >> 2002 >> C3500 HD 8.1 G, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 8.1L >> Description and Operation >> Fuel System Description >> Fuel Pressure Regulator Assembly
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Fuel Pressure Regulator Assembly

Fig 1: Fuel Pressure Regulator
G01599051Courtesy of GENERAL MOTORS CORP.

The fuel pressure regulator is a vacuum operated diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure and intake manifold vacuum on the other side. The fuel pressure regulator compensates for changes in intake manifold vacuum by changing the fuel pressure. In this way, the fuel pressure regulator maintains a constant pressure differential across the injectors at all times.