Adjusting Housing Pressure Regulators

The HPCA pressure regulator is installed in the pump cover with a fitting that adapts it to the fuel return pipe. The HPAA pressure regulator is installed in the "outlet" side of the HPAA solenoid which is located in the fuel return pipe. It also has a fitting that adapts the fuel return line to it.






The Housing Pressure Regulators are adjusted by rotating the adjustment screw with a 1/8" HEX key. Rotating the adjustment screw clockwise (when viewed from the end that the tool is inserted) increases housing pressure. One turn of the screw will change housing pressure 22 kPa (3.2 psi). See Figures 1 and 2.