MBE 900 DDEC VI Troubleshooting – Section 13.1 Aerated Fuel

Section 13.1
Aerated Fuel

To determine if aerated fuel is causing lack of power, perform the following steps:‪

1. Test for aerated fuel.
2. Disconnect the fuel line return hose from the fitting located at the fuel tank; refer to OEM guidelines.
3. Place the open 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.‪

4. Start and run the engine.
5. Operate the engine at 1000 rpm.
6. Visually check to see if air bubbles are rising to the surface of the fuel that collects within the container.
   1. If air bubbles are not present, shut down the engine, check for high fuel pressure; refer to "13.2 High Fuel Pressure" .
   2. If air bubbles are present, shut down the engine; refer to "13.1.1 Aerated Fuel Resolution" .

Section 13.1.1
Aerated Fuel Resolution

Perform the following steps to resolve aerated fuel condition:‪

1. Tighten all fuel line connections between fuel tank and fuel pump; refer to OEM guidelines.
2. Visually inspect all fuel lines between fuel tank and fuel pump for leaks.
3. Repair damaged components as required; refer to OEM guidelines.
4. Verify aerated fuel resolution; refer to "13.1.1.1 Test the Engine with Aerated Fuel Resolution" .

Section 13.1.1.1
Test the Engine with Aerated Fuel Resolution

Perform the following steps to determine if aerated fuel resolution has resolved lack of power condition:‪

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. Start and run the engine.
2. Run the engine at idle with a no-load condition for approximately five minutes, allowing the engine coolant to reach normal operating range.
3. Test drive the vehicle to ensure lack of power has been resolved.
   1. If no lack of power occurred during the test drive, no further troubleshooting is required. Shut down the engine.
   2. If lack of power occurred during the test drive, shut down the engine. Check for high fuel pressure; refer to "13.2 High Fuel Pressure" .