TUBE AS 3965351 - Caterpillar

The probable causes of high fuel temperature
Associated codes
Fuel level in the tank
Fuel temperature sensor
Fuel return pressure regulator
Restriction in the fuel lines
Fuel injectorUse this procedure in order to troubleshoot high fuel temperature. Use this procedure if one of the following event codes is active. Refer to Troubleshooting, "Event Codes" for information about event codes, and the engine monitoring system.
Table 1
Event Codes
CDL Code Code Description Comments
E363(1) High Fuel Supply Temperature The fuel temperature is above an acceptable level.
If equipped, the action lamp will illuminate.
The code is logged.
E363(2)
E363(3) Test Step 1. Check for Active Diagnostic Codes
Check for active codes and check for logged codes on Caterpillar Electronic Technician (ET).
Check Cat ET for any associated codes that are listed in Table 2. Troubleshoot any active codes before continuing with this procedure.
Table 2
Associated Codes
CDL Code WCI
E198 (1)
E198 (2) Expected Result:No associated codes that are active or logged.Results:
OK - No associated codes are active or logged. Proceed to Test Step 2.
Not OK - Associated codes are active or logged.Repair: Troubleshoot any active codes before continuing with this procedure.STOPTest Step 2. Check the Fuel Level in the Fuel TankCheck the fuel level in the fuel tank.Expected Result:The fuel level in the tank is acceptable.Results:
OK - The fuel level is OK. Proceed to Test Step 3.
Not OK - The fuel level low.Repair: Fill the tank. Verify that the problem has been resolved.If the problem has not been resolved, proceed to Test Step 3.Test Step 3. Inspect the Fuel Lines
Illustration 1 g02138939
Fuel lines for the engine
Visually inspect the fuel lines between the priming pump and the inlet to the cylinder heads that are at the back of the engine. Inspect the fuel return line from the cylinder heads to the fuel tank. Inspect the lines for restrictions, pinching, and swelling. Also, inspect the fuel cooler. Refer to Systems Operation/Testing and Adjusting, "Fuel System - Inspect" for additional information.Expected Result:The fuel lines and the fuel cooler are in good repair.Results:
OK - The fuel lines and the fuel cooler are OK. Proceed to Test Step 4.
Not OK - A problem has been identified with the fuel lines and/or the fuel cooler.Repair: Perform the necessary repairs. Verify that the problem has been resolved.If the problem is not resolved, proceed to Test Step 4.Test Step 4. Replace the Temperature SensorReplace the fuel temperature sensor.Expected Result:The E363 is no longer active.Results:
OK - The code is no longer active.Repair: Return the engine to service.STOP
Not OK - The E363 code remains active. Proceed to Test Step 5.Test Step 5. Fuel Return Pressure Regulator
Illustration 2 g02138940
Location of the fuel return pressure regulator (left rear engine view)
Replace the fuel return pressure regulator. Verify that the problem has been resolved.
Use Cat ET to check the fuel temperature. Expected Result:The fuel temperature is within specifications.Results:
OK - The fuel temperature is within specifications.Repair: The problem has been resolved. Return the unit to service.STOP
Not OK - The fuel temperature is not within specifications. The event code for high fuel temperature remains active. Proceed to Test Step 6.Test Step 6. Perform a Cylinder