Fuel Pump: Testing and Inspection

WARNING: FUEL SYSTEM PRESSURE MUST BE RELEASED BEFORE A FUEL SYSTEM HOSE OR COMPONENT IS DISCONNECTED.

The fuel system operates at approximately 338 kPa (49 ± 2 psi).
1. Perform fuel system pressure release procedure.
2. Remove fuel Supply hose quick connector from the chassis line (at the engine). Refer to Quick Connect Fittings.

Fuel Pressure Test Adapter:

3. Connect Fuel Pressure Gauge C-4799 to Fuel Pressure Test Adapter 6539. Install the adapter between fuel supply hose and chassis fuel line assembly.

CAUTION: When using the ASD Fuel System Test, the ASD relay and fuel pump relay remain energized for 7 minutes or until the test is stopped, or until the ignition switch is turned to the Off position.

4. Place the ignition key in the ON position. Using the DRB scan tool, access ASD Fuel System Test. The ASD Fuel System Test will activate the fuel pump and pressurize the system.
- If the gauge reading equals 338 kPa (49 ± 2 psi) further testing is not required. If pressure is not correct, record the pressure.
- If pressure is above specifications, check for a kinked or restricted fuel return tube (from filter to pump module). If the fuel return tube is not pinched or restricted, replace the fuel pressure regulator.

Fuel Pressure Below Specifications:

- If pressure is below specifications, refer to Fuel Pressure Below Specifications chart.