Fuel Pressure: Testing and Inspection

FUEL LINE PRESSURE / FUEL PRESSURE HOLD INSPECTION

SST Fuel Gauge With Pressure Release Hose:

WARNING: Before performing the following operation, release the fuel pressure from the fuel system to reduce the possibility of injury or fire.

1. Install the Special Service Tool SST.
2. Key ON, engine off.
3. Connect the SST New Generation Star (NGS) tester to the data link connector and select Active Command Mode.
4. Select Output Test Mode. Press MODE to change to the "ALL ON" mode, and press start to run fuel pump.
5. Turn relay OFF.
6. Observe the fuel pressure.

Fuel pressure 240-280 kPa (35-40 psi)

^ Zero or pressure low:
- Check the fuel pump. If as specified, the fuel line or fuel filter might be clogged or restricted.

^ Pressure high:
- Perform pressure regulator high pressure inspection.

7. Observe the fuel pressure after 1 min.

Fuel pressure within 34 kPa (3 psi) of reading in test step 5.

8. If not as specified, perform the following inspections:
^ Pressure regulator diaphragm inspection.
^ Injector fuel leakage.
^ If results of fuel line pressure and pressure hold inspection are OK, perform "Fuel Line Pressure Under Load Inspection".

SST Fuel Gauge With Pressure Release Hose:

FUEL LINE PRESSURE UNDER LOAD INSPECTION

WARNING: Before performing the following operation release the fuel pressure from the fuel system to reduce the possibility of injury or fire.

1. Install the SST.
2. Disconnect the vacuum hose from the pressure regulator and plug it.
3. Start the engine and drive the vehicle under heavy acceleration.
4. Verify that the fuel line pressure does not increase or decrease more than 20 kPa (3 psi) during heavy acceleration.
5. If not as specified, perform the following inspection:
^ Fuel vapor valve

6. If the fuel vapor valve is ok, replace the fuel filter.