MBE 4000 DDEC VI Troubleshooting – Section 12.3 Insufficient Fuel Flow

Section 12.3
Insufficient Fuel Flow

To determine if insufficient fuel flow is causing rough running or stalling, do the following steps:‪

1. Perform Fuel Flow Test #3 and measure the fuel return flow rate. Refer to "3.5 Test #3 Flow Test — At Fuel Filter" .
2. Analyze the fuel flow test results.
   1. If the fuel rate is 0.9 L/min. (0.2 gal/min.) or more, no further troubleshooting is required. Contact Detroit Diesel Customer Support Center at 313-592-5800.
   2. If the fuel rate is less than 0.9 L/min. (0.2 gal/min.), resolve the insufficient fuel flow; refer to "12.3.1 Insufficient Fuel Flow Resolution" .

Section 12.3.1
Insufficient Fuel Flow Resolution

Perform the following steps to resolve the insufficient fuel flow:‪

1. Replace the fuel filter(s); Refer to the MBE 4000 Service Manual (6SE420), Chapter 2, “Fuel System — Fuel Filter”.

   Note: Always fill the filter(s) with clean fuel oil 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 fuel return check valve for restrictive movement.
4. Inspect the fuel pump drive assembly. If damage is found, repair as necessary; refer to MBE 4000 Service Manual (6SE420), Chapter 2, “Fuel System — Fuel Pump Drive”.
5. Verify repairs done to correct insufficient fuel flow; refer to "12.3.1.1 Test the Engine with Resolved Fuel Flow" .

Section 12.3.1.1
Test the Engine with Resolved Fuel Flow

Perform the following steps to determine if the fuel flow resolution resolved rough running or stalling:‪

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 capacity for approximately five minutes, allowing the engine coolant to reach normal operating range, 88-96°C (190-205°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. Contact Detroit Diesel Customer Support Center at 313-592-5800.