HOSE AS 3966928 - Caterpillar

Illustration 1 g02051497
Secondary fuel filter mounting
(1) Fuel temperature sensor
(2) Fuel filter differential pressure sensor
(3) Fuel pressure sensor (filtered fuel pressure) Note: Do not use the sampling port for measuring the fuel pressure.
Remove fuel pressure sensor (3).
Install a 8T-7860 Connector into the port of the pressure sensor (3).
Install the 110-6349 Fitting As onto the 8T-7860 Connector.
Install a 8T-0855 Pressure Gauge onto a 6V-3990 Coupler.
Install the 6V-3990 Coupler onto the 110-6349 Fitting As.
Record the fuel pressure on the pressure gauge. Record the data in Table 3.
Table 3
Engine RPM Fuel Pressure from Cat ET Fuel Pressure from the Mechanical Gauge
700
1850 Expected Result:The value of the fuel pressure is within 137 kPa (20 psi) of the fuel pressure reading that is shown in Cat ET.Results:
OK - The fuel pressure readings are comparable. Proceed to Test Step 5.
Not OK - The value of the fuel pressure is not within 137 kPa (20 psi) of the fuel pressure reading that is shown in Cat ET.Repair: Replace the pressure sensor. Verify that the problem has been resolved.If the problem is not resolved, proceed to Test Step 5.Test Step 5. Verify that the Fuel Pressure is Within SpecificationsVerify that the recorded fuel pressure is above the minimum acceptable fuel specifications. Refer to Table 4 for the minimum acceptable specifications.
Table 4
Engine RPM Minimum Acceptable Fuel Pressure
700 500 kPa (73 psi)
1850 650 kPa (94 psi) Expected Result:The fuel pressure is within specifications.Results:
OK - The fuel pressure is above the minimum acceptable pressure specifications. Proceed to Test Step 7.
Not OK - The fuel pressure is not above the minimum acceptable pressure specifications. Proceed to Test Step 6.Test Step 6. Replace the Fuel Filters
Replace the primary filter, the secondary filter, and the tertiary fuel filters. Note: The fuel system will need to be primed after the filters are replaced.
Verify that the fuel pressure is above the minimum acceptable pressure specifications. Refer to Table 4 for the proper specifications. Expected Result:The fuel pressure meets the minimum acceptable specifications.Results:
OK - The fuel pressure meets the minimum acceptable specifications.Repair: Return the engine to service.STOP
Not OK - The fuel pressure does not meet the minimum acceptable specifications. Proceed to Test Step 7.Test Step 7. Check for Air in the Fuel SystemCheck for air in the fuel. Refer to Systems Operation/Testing and Adjusting, "Air in Fuel - Test" for the proper procedure.Expected Result:The system is not contaminated with air.Results:
OK - Air is not found in the fuel system. Proceed to Test Step 8.
Not OK - Air bubbles have been found in the fuel system.Repair: Refer to Systems Operation/Testing and Adjusting, "Air in Fuel - Test" for the proper repairs.If the problem is not resolved, proceed to Test Step 8.Test Step 8. Replace the Fuel Pressure Regulator and the Return Check Valve
Illustration 2 g02140693
(4) Fuel return pressure regulator
(5) Return check valve to the fuel tank
Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to