MBE 4000 DDEC VI Troubleshooting – Section 9.5 Aerated Fuel

Section 9.5
Aerated Fuel

To determine if aerated fuel is causing excessive exhaust smoke, perform the following steps:‪

1. Disconnect the fuel line return hose from the fitting located at the fuel tank; refer to OEM guidelines.
2. Place the opened end of the fuel line into a suitable container.

   PERSONAL INJURY ‪
   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

3. Start the engine.
4. Run the engine at 1000 rpm.
5. Visually check to see if air bubbles are rising to the surface of the fuel within the container.
   1. If air bubbles are present, repair is necessary; refer to "9.5.1 Aerated Fuel Resolution" .
   2. If air bubbles are not present, check for a low compression. Shut down the engine; refer to "9.6 Faulty Fuel Nozzle" .

Section 9.5.1
Aerated Fuel Resolution

Perform the following steps for aerated fuel resolution:‪

1. Shut down the engine.
2. Tighten all fuel line connections between fuel tank and fuel pump; refer to OEM guidelines.
3. Visually inspect all fuel lines between fuel tank and fuel pump for leaks.
4. Replace damaged components as required.
5. Verify aerated fuel resolution corrected the excessive exhaust smoke condition; refer to "9.5.1.1 Test Engine with Aerated Fuel Resolution" .

Section 9.5.1.1
Test Engine with Aerated Fuel Resolution

To determine if aerated fuel resolution resolved the excessive exhaust smoke concern, perform the following steps:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

1. Attempt to start and run the engine, if the engine starts and runs with no exhaust smoke, no further troubleshooting is required. Shut down the engine.
2. If the engine still has excessive exhaust smoke, check for faulty fuel nozzle; refer to "9.6 Faulty Fuel Nozzle" .