Series 50 – Section 29.7 Fuel Oil Flow Test

Section 29.7
Fuel Oil Flow Test

Perform the following test to check for proper fuel oil flow:‪

1. Disconnect the fuel return hose from the fitting at the fuel tank, refer to OEM guidelines, and hold the open end in an approved container.
2. Start and run the engine at maximum no-load and measure the fuel flow. Nominal fuel return spill with the standard 2.03 mm (0.080 in.) restricted fitting is 246 L/hr (65 gal/hr).
   1. If the fuel flow rate is 246 L/hr (65 gal/hr), no further testing is required.
   2. If the fuel flow rate is less than 246 L/hr (65 gal/hr), resolve the low fuel rate; refer to "29.7.1 Low Fuel Rate Resolution" .

Section 29.7.1
Low Fuel Rate Resolution

Perform the following steps to resolve the low fuel oil rate:‪

1. Replace the fuel filters; refer to "2.7.1 Replacement of Fuel Filter" .
2. Visually inspect fuel oil lines for pinching, kinking, and other damage. Repair or replace as necessary; refer to OEM guidelines.
3. Remove and visually inspect the check valve for a correct restricted fitting. Replace if necessary; refer to "2.8.2 Fuel Return System Check Valve" .
4. Verify low fuel oil rate resolution; refer to "29.7.1.1 Test the Engine with Replaced Fuel Oil Filters, Check Valve, and Fuel Oil Line Connections" .

Section 29.7.1.1
Test the Engine with Replaced Fuel Oil Filters, Check Valve, and Fuel Oil Line Connections

Perform the following steps to determine if the low fuel rate resolution resolved the improper fuel oil flow rate:‪

1. Start and run the engine at maximum no-load and measure the fuel flow. Nominal fuel return spill with the standard 2.03 mm (0.080 in.) restricted fitting is 246 L/hr (65 gal/hr).
   1. If the fuel flow rate is 246 L/hr (65 gal/hr), no further testing is required.
   2. If the fuel flow rate is less than 246 L/hr (65 gal/hr); call the Detroit Diesel Technical Service Group.