Fuel Injectors & Pumps – Section 8.5 Series 50/60 DDEC Insufficient Fuel Flow Test

Section 8.5
Series 50/60 DDEC Insufficient Fuel Flow Test

Perform the following steps to resolve the insufficient fuel flow:‪

1. Replace the fuel filter(s).

   Note: Always fill the filter(s) with clean fuel before installing. Turn the filter(s) until they contact the gasket fully. Then, turn them an additional two-thirds by hand.

2. Inspect the fuel lines for restrictions due to pinching, kinking or other damage. If damage is found, repair as necessary; refer to OEM guidelines.
3. Inspect the cylinder head for a correct restricted fitting. If an incorrect fitting is found, replace with a new fitting. See Additional Information (Shop Notes) of Section 2 of current Series 60 service manual (6SE483) or Series 50 service manual (6SE50).
4. Inspect the fuel return check valve for restrictive movement, (see Section 2.1 of current service manual).
5. Inspect the fuel pump drive assembly. If damage is found, repair as necessary. See current service manual.
6. Verify repairs done to correct insufficient fuel flow.

Perform the following steps to test the engine:‪

1. Start and run the engine.
2. Run the engine at idle with a no-load for approximately five minutes, allowing the engine coolant to reach normal operating range, 88-96°C (190-210°F).
   1. If the engine is not running rough or stalling, no further troubleshooting is required. Shut down the engine.
   2. If the engine is running rough or stalling, shut down the engine. Check for high fuel oil temperature return, or air in the fuel. See current service manual.