Repair Procedures

Fuel Pressure Inspection (Low-Pressure System)

1. 1
   Relieve the residual fuel pressure in the fuel line. (Refer to Fuel System - Repair Procedures - "Relieve Residual Fuel Pressure in Fuel Line").

   When the fuel pump fuse is removed, a diagnostic trouble code (DTC) is stored. Clear the DTC with GDS after completing the "Relieve Residual Fuel Pressure in Fuel Line" procedure.

2. 2
   Install the Special Service Tool (SST).

   1. Disconnect the low-pressure fuel feed hose from the low-pressure inlet of the high-pressure fuel pump.

      Some residual pressure may remain even after releasing the residual fuel pressure in the fuel line. Therefore, cover the hose connection with a shop towel to prevent fuel from spilling before disconnecting any fuel connection.

   2. Install the special service tool to measure the fuel pressure between the low-pressure fuel feed hose and the low-pressure inlet of the high-pressure fuel pump (see figure below).

      

3. 3
   Inspect for fuel leaks at the low-pressure fuel feed hose connections, the low-pressure inlet of the high-pressure fuel pump, and the SST components with the ignition ON.
4. 4
   Measure the fuel pressure.

   1. Start the engine and measure the fuel pressure at idle. Fuel pressure: 480 ~ 500 kPa (4.9 ~ 5.1 kgf/cm², 69.7 ~ 72.5 psi)

      If the fuel pressure is out of specification, repair or replace the related part (see the table below).

      Fuel Pressure	Cause	Related Part
      Too low	Clogged fuel filter	Fuel filter
      	Fuel leakage	Fuel Pressure Regulator
      Too high	Fuel pressure regulator stuck	Fuel Pressure Regulator

   2. Stop the engine, then check the fuel pressure gauge reading for changes. Specification: The gauge reading should be held for approximately 5 minutes after the engine is stopped.

      If the gauge reading is not held, repair or replace the related part (see the table below).

      Fuel Pressure (After Engine Stop)	Cause	Related Part
      Fuel pressure drops slowly	Injector leakage	Injector
      Fuel pressure drops immediately	Fuel pump check valve stuck open	Fuel pump

   3. Turn the ignition off.
5. 5
   Relieve the residual fuel pressure in the fuel line. (Refer to Fuel System - Repair Procedures - "Relieve Residual Fuel Pressure in Fuel Line").

   When the fuel pump fuse is removed, a diagnostic trouble code (DTC) is stored. Clear the DTC with GDS after completing the "Relieve Residual Fuel Pressure in Fuel Line" procedure.

6. 6
   End of test

   1. Remove the special service tool (SST) from the low-pressure fuel feed hose and the low-pressure inlet of the high-pressure fuel pump.
   2. Connect the low-pressure fuel feed hose to the low-pressure inlet of the high-pressure fuel pump.

Release Fuel Line Residual Pressure

Whenever the high-pressure fuel pump, high-pressure fuel line, fuel feed hose or injector is removed immediately after engine shutdown, injury may be caused by high-pressure fuel spray. Release the residual pressure in the high-pressure fuel line by referring to the "Fuel Residual Pressure Release Procedure" below before removing any high-pressure fuel system components.

Wear protective goggles and fuel-resistant gloves.

1. 1
   Turn the ignition OFF and disconnect the negative battery cable.
2. 2
   Remove the fuel pump fuse (A).

   

3. 3
   Connect the negative battery cable.
4. 4
   Run the engine for approximately 1 minute to reduce the pressure in the low pressure line.
5. 5
   Turn the engine off.
6. 6
   Disconnect the quick-connector of the low pressure fuel line at the high pressure pump. Use rags to cover the opening and collect spillage while removing the fuel line.
7. 7
   Start the engine and let it idle until the engine stops. At this point, the pressure should be below 30 psi.
8. 8
   Continue with the service or repair. Use a shop towel to cover the opening and collect any spilled fuel when opening the high-pressure system.
9. 9
   Reinstall/reconnect all components in the reverse order of removal. Start the engine, confirm proper operation, and make sure there are no fuel leaks.
10. 10
    After completion, clear the DTCs using the GDS diagnostic scan tool (the procedure described above will set DTCs).