14. Combustion Gas In The Fuel Rail Test

14. COMBUSTION GAS IN THE FUEL RAIL TEST

Purpose:
The purpose of this test is to check if any combustion gas leaks past the combustion gasket.

Combustion Gas In The Fuel Rail Test:

Recommended Procedure:

NOTE:
- The compression pulses in the latex balloon indicate the combustion gas is leaking into the fuel rail.
- Additional DTCs may result during this procedure.

- Disconnect the low pressure fuel pump electrical connector.
- Disconnect the fuel injector return line at the check valve located near the left cylinder head. Refer to the Fuel Delivery and Air Induction, Fuel Charging and Controls.
- Install a latex balloon over the fuel return line and secure with a tie strap.
- Remove the glow plugs from cylinder numbers 2 through 8, leaving the cylinder number 1 glow plug installed. Crank the engine and observe the latex balloon for compression pulses. Refer to the Ignition System, Glow Plug system.
- If no compression pulses are present, remove the cylinder number 1 glow plug and install the glow plug in cylinder number 2. Crank the engine and observe the latex balloon for compression pulses.
- Repeat the test moving the glow plug to cylinder numbers 3 through 8 and continue testing all cylinders. Record the cylinder numbers that indicate compression pulses in the latex balloon.
- For cylinders that leak combustion gas into the fuel return line as indicated by compression pulses in the latex balloon, remove the fuel injector and install new O-rings, combustion gasket and fuel injector hold down clamp assemblies. Refer to the Fuel Delivery and Air Induction, Fuel Charging and Controls.

Carry out the Combustion Gas In The Fuel Rail Test to verify the repair. After the repair is verified, carry out the High Pressure Fuel System Test. 25. High Pressure Fuel System Test

Possible Causes:
- Fuel injector combustion gasket
- Fuel injector O-rings
- Fuel injector loose
- Fuel injector

Tools Required:
- Latex balloons
- Tie straps