Warning: Before disconnecting the fuel lines, relieve the pressure in the fuel system, otherwise pressurized fuel will leak out of the fuel system.
2. Disconnect the high-pressure fuel hose from the fuel pump (high-pressure side) (Fig. 6.11).
Fig. 6.11. The place where the high-pressure fuel hose is disconnected from the fuel pump on a vehicle manufactured since 1999
Fig. 6.12. The place where the high-pressure fuel hose is disconnected from the fuel pump on a vehicle manufactured since 2000
Warning: Cover the hose disconnection area with a towel to prevent fuel under residual pressure from splashing out.
3. Unscrew the coupling and bypass bolt from the special tool (transition hose) and connect the special tool to the transition hose instead (Fig. 6.13).
Fig. 6.13. Assembly of fuel pressure measuring instruments
4. Install the assembled special fuel pressure measuring tool.
When using a fuel pressure sensor (special tool)
- (1) Install the special tool (for measuring pressure) between the high-pressure fuel hose and the high-pressure fuel pump.
- (2) Connect the fuel pressure sensor to the special fuel pressure measuring tool with a spacer between them.
- (3) Connect the fuel pressure sensor wire to the power source (cigarette lighter) and to the MUT-II device.
When using a pressure gauge
- (1) Install the pressure gauge on the special pressure measuring instrument, placing a sealing ring or gasket between them (Fig. 6.14).
- (2) Install the special tool with pressure gauge assembly between the high pressure fuel hose and the high pressure fuel pump.
Fig. 6.14. Assembly of special tools and pressure gauge for measuring fuel pressure
5. Connect the MUT-II device to the diagnostic connector.
Warning: Before disconnecting or connecting the MUT-II, turn off the ignition to avoid damage.
6. Turn the ignition switch to the ON position, but do not start the engine.
7. Select # 07 from the MUT-II Actuator test menu to activate the low-pressure fuel pump (on the fuel tank side). Make sure that there are no leaks at the connection points.
8. Turn off the Actuator test mode or turn the ignition switch key to the OFF position.
9. Start the engine and let it idle.
10. With the engine idling, measure the fuel pressure.
Nominal pressure: about 324-343 kPa
11. Make sure that the fuel pressure at idle does not drop even after pressing the accelerator pedal several times.
12. If any fuel pressure is out of tolerance, diagnose and repair according to the Fuel System Pressure Diagnostic Chart.
13. Stop the engine and read the fuel pressure value on the pressure gauge, which should not change.
If the fuel pressure has dropped significantly after 2 minutes, diagnose and repair according to the Fuel System Pressure Drop Diagnosis Table.
Fuel System Pressure Diagnostic Chart
Fuel System Pressure Loss Diagnostic Chart
14. Reduce the residual fuel pressure in the fuel system.
15. Remove the pressure gauge and special tools from the fuel distribution line. Cover the connection with a towel to prevent fuel from splashing out due to residual pressure in the fuel line.
16. Replace the sealing ring at the end of the high-pressure fuel hose. Before installing the ring, lubricate its surface with a layer of engine oil.
17. Connect the high-pressure fuel hose to the fuel distribution line and tighten the flange mounting bolts to the specified torque.
18. Check the fuel system for leaks.
19. Disconnect MUT-II from the diagnostic connector.