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 injector
Use this procedure in order to troubleshoot high fuel temperature. Use this procedure if one of the following event codes is active. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. Refer to Troubleshooting, "Engine Monitoring Parameters" for information about engine events.
| Engine Events | ||
|---|---|---|
| J1939 Code and Description | Conditions that Generate the Code | System Response |
| 174-0 Engine Fuel Temperature 1 : High - most severe (3) | The fuel temperature is above an acceptable level. | The code is logged. |
| 174-15 Engine Fuel Temperature 1 : High - least severe (1) | ||
| 174-16 Engine Fuel Temperature 1 : High - moderate severity (2) | ||
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.
| Associated Codes | |
| J1939 Code | Description |
| 5580-17 | Engine Filtered Fuel Delivery Pressure (After Secondary Filter Gauge): Low - least severity (1) |
| 5580-18 | Engine Filtered Fuel Delivery Pressure (After Secondary Filter Gauge): Low - moderate severity (2) |
Expected Result:
There are no associated codes that are active or logged.
Results:
- OK - No associated codes are active or logged. Proceed to Test Step 2.
- Not OK - There are associated codes that are active or logged.
Repair: Troubleshoot any active codes before continuing with this procedure.
STOP
Test Step 2. Check the Fuel Level in the Fuel Tank
Check the fuel level in the fuel tank.
Expected Result:
The fuel level in the tank is acceptable.
Results:
- OK - The fuel level is acceptable. Proceed to Test Step 3.
- Not OK - The fuel level is not acceptable.
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 | g02158580 |
|
Fuel lines for the engine (typical engine view) | |
- 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 Sensor
- Replace the fuel temperature sensor.
- The 174 code is no longer active.
Expected Result:
Results:
- OK - The code is no longer active.
Repair: Return the engine to service.
STOP
- Not OK - The 174 code remains active. Proceed to Test Step 5.
Test Step 5. Fuel Return Pressure Regulator
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| 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 Cutout Test
- Perform a "Cylinder Cutout Test" in Cat ET.
Results:
- Problem Identified -
Repair: Replace the identified injectors. Verify that all trim files are installed into the ECM correctly. Refer to Troubleshooting, "Injector Trim File - Install". Repeat the "Cylinder Cutout Test" after performing the necessary repairs. Repeat the process until all the injectors are operating properly.
STOP