Fuel Pressure: Testing and Inspection

Fig. 7 Fuel Pressure Test Port - Typical:

NOTE: The fuel system operates at approximately 331 kPa (48 psi). Check fuel system pressure at the test port on the fuel rail (Fig. 7).

Fig. 8 Checking Fuel Pressure at Intake Manifold - Typical:

1. Remove cap from fuel pressure test port on fuel rail.
2. Connect Fuel Pressure Gauge C-4799B to test port (Fig. 8).

CAUTION: When using the Auto Shutdown (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.

3. 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 331 kPa (48 PSI) further testing is not required. If pressure is not correct, record the pressure.
- If fuel pressure is below specifications, refer to the Fuel Pressure Diagnosis Chart (Fig. 9) below.
- If fuel pressure is above specifications (54 psi or higher) check for a kinked or restricted fuel supply line. If the supply line is not kinked or restricted, replace the Fuel Filter/Pressure Regulator.

Fig. 9 Fuel Pressure Diagnosis Chart:

4. Replace Pressure test port cap when finished doing pressure test.