Info - 6.6L LB7 Duramax Diesel Fuel Pressure Regulator Replacement

The fuel pressure regulator, P/N 97728979, is now serviceable separate from the fuel injection pump.

If the Service Manual diagnostics lead to the replacement of the fuel pressure regulator, inspect the inner tip of the regulator (see illustration) for corrosion upon its removal. The inner tip of a fuel pressure regulator from an uncontaminated fuel system will be smooth with tan colored fuel deposits, but it will not be blackened with heavy scaling or pitting.

If blackened corrosion and pitting is found on the inner tip of the regulator, the integrity of the fuel injection pump has been compromised and the pump must be replaced. Replace the fuel filter element and clean the fuel system using Service Manual procedures. Injector replacement is not necessary, as the fuel injection pump is the most susceptible component to corrosion damage. After repairs are completed, re-evaluate the vehicle's performance to ensure no additional concerns are present. Some fuel additives emulsify water into the fuel and allow the water to get past the fuel filter/water separator. Fuel additives can be introduced by the customer or by the fuel retailer. Advise the customer of possible fuel source issues and recommend against the use of aftermarket fuel additives.

Parts are currently available from GMSPO.