Disconnect the high pressure fuel hose (1) from the fuel pump.
Disconnect the coupling and bypass bolt from the hose and connect a special adapter instead.
Install a pressure gauge between the high pressure fuel hose and the high pressure fuel pump.
Connect the dedicated fuel pressure sensor to the fuel pressure gauge with a spacer between them.
Connect the dedicated fuel pressure sensor to the power supply (cigarette lighter) and to the tester.
If a manometer is used, then follow the steps:
- Mount the pressure gauge on the pressure gauge with an O-ring or gasket between them;
- Install the gauge assembly between the high pressure fuel hose and the high pressure fuel pump;
- Connect the tester to the diagnostic socket.
WARNING: Always turn off the ignition before connecting or disconnecting the tester.
The engine does not start, turn the ignition key to the ON position (ON).
By selecting the appropriate menu item of the tester «Checking actuators», actuate the low pressure fuel pump (in the fuel tank). Make sure there are no leaks at the connections.
After completing the test mode, turn the ignition key to the OFF position (OFF).
After starting the engine, let it run at idle.
Measure the fuel pressure while the engine is idling. The required value is 324 kPa.
Fuel pressure at idle should not drop even after a few presses on the gas pedal.
If the fuel pressure does not correspond to the required one, then troubleshoot and eliminate them in accordance with the table.
Symptom | Possible reasons | Remedy |
Reduced fuel pressure | Clogged fuel filter | Replace fuel filter |
Drop in fuel pressure after pressing the gas pedal | Fuel leaks into the fuel return line due to poor seating of the low fuel pressure regulator valve or weakening of its spring | Replace low fuel pressure regulator |
Increased fuel pressure | Reduced pressure generated by the low pressure fuel pump | Replace low pressure fuel pump |
Stuck valve in low fuel pressure regulator | Replace low fuel pressure regulator | |
Clogged fuel return hose to fuel tank | Clean or replace fuel hose or tube |
Stop the engine and check the fuel pressure gauge for changes. The fuel system is OK if the pressure in the fuel line does not decrease within 2 minutes. If the pressure drops, then troubleshoot and eliminate it in accordance with the table.
Symptom | Possible reasons | Remedy |
After the engine is stopped, the fuel pressure gradually drops | Leaks at the low fuel pressure regulator valve | Replace low fuel pressure regulator |
After the engine is stopped, the fuel pressure drops instantly | Low pressure fuel pump check valve remains open | Replace low pressure fuel pump |
Reduced fuel pressure | Fuel leaks into the fuel return line due to poor seating of the high pressure fuel regulator valve or weakening of its spring | Replace high pressure fuel pump |
Fuel pressure drops after pressing the gas pedal | Reduced pressure generated by the high pressure fuel pump | Replace high pressure fuel pump |
Increased fuel pressure | Stuck High Pressure Fuel Regulator Valve | Replace high pressure fuel pump |
Clogged fuel return hose to fuel tank | Clean or replace fuel hose or tube |
Release residual pressure from the fuel line.
Disconnect the fuel pressure gauge and special tool from the high pressure fuel pump.
Replace the gasket on the high pressure fuel hose with a new one. Before installing the gasket, apply a thin layer of engine oil to its surface.
Connect the fuel hose to the high pressure fuel pump and tighten the flange mounting bolts to the correct torque.
Check connections for fuel leaks.
Disconnect the tester.