25. High Pressure Fuel System Test

25. HIGH PRESSURE FUEL SYSTEM TEST

NOTE:
- Disregard any DTCs set as a result of the High Pressure Fuel System Test.
- Carry out the Electric Fuel Pump Pressure Test before carrying out the High Pressure Fuel System Test. 11. Electric Fuel Pump Pressure Test

Purpose:
The purpose of this test is to determine if the high pressure fuel system is able to reach and maintain the requested desired fuel pressure for a calibrated amount of time. This procedure may be used to assist in diagnosing hard start/no start or driveability concerns. This test can also be run to check for engine oil level increase due to leaks.

High Pressure Fuel System Test

NOTE: Depending on the engine state the fuel rail pressure may vary at idle from 34.47 MPa (5,000 PSI) to 51.71 MPa (7,500 PSI).

- Use the scan tool to carry out the High Pressure Fuel System Test.
- Visually check for engine compartment fuel leaks during this test.







Recommended Procedure:

NOTE: Follow the scan tool directions when carrying out the high pressure fuel system test.

This test determines if the high pressure fuel system is able to maintain the requested fuel pressure for a calibrated amount of time.
- Turn off all accessories. If the vehicle is equipped with a PTO system or auxiliary idle control, it must be turned off to carry out the high pressure fuel system test.
- Refer to the scan tool operating manual for instructions.
- Ignition in the OFF position.
- Carry out the High Pressure Fuel System Test.
- Wait a minimum of 10 minutes and recheck the engine oil level.
- If the measured variation is outside of the specifications, no visible fuel leaks are present, and the engine oil level was correct in the Check Engine Oil Level test, GO to Pinpoint Test ME. Test ME: Fuel Pump Control - High Pressure Fuel Injection Pump
- If the measured variation is outside of the specifications, no visible fuel leaks are present, and the engine oil level was overfull in the Check Engine Oil Level lest, carry out the Fuel System Leak Test to continue diagnosis. 26. Fuel System Leak Test
- If the measured variation is outside of the specifications or the engine oil level has increased during this test, carry out the High Pressure Fuel System Test With Valve Covers Off Running to continue diagnosis. 22. High Pressure Fuel System Test With Valve Covers Off Running

Tools Required:
Scan tool