- Low coolant temperature
- Check for intermittent diagnostic codes
- Unstable fuel supply
- Unstable fuel injection
- Restriction in the air inlet and exhaust system
Note: If the problem is intermittent and the problem cannot be duplicated, refer to Troubleshooting, "Power Is Intermittently Low or Power Cutout Is Intermittent".
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high rpm, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.
Cold mode is activated whenever the engine coolant temperature falls below a predetermined value. Monitor the status screen on Caterpillar Electronic Technician (ET) in order to verify that the engine has exited cold mode. Observe the reading for coolant temperature on the Cat ET.
Certain diagnostic codes may cause poor performance. Connect Cat ET and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.
- Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. If necessary, add fuel to the fuel tank. If the engine has been run out of fuel, it will be necessary to purge the air from the fuel system. Refer to Operation and Maintenance Manual for the correct procedure.
- Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
- Check the fuel lines for the following problems: restrictions, collapsed lines, pinched lines and loose connections. If problems are found with the fuel lines, repair the lines and/or replace the lines.
- Check the fuel tank for debris or foreign objects which may block the fuel supply.
- Prime the fuel system if any of the following procedures have been performed:
- Replacement of the fuel filters
- Service on the low pressure fuel supply circuit
- Replacement of unit injectors
Note: Check the fuel system for air. Refer to Systems Operation/Testing and Adjusting for information that is related to checking the fuel system for air.
- Replacement of the fuel filters
- Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the engine's Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
- Check the filtered fuel pressure while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting for the test procedure and for the correct pressure values.
If the fuel pressure is low, replace the fuel filters. Clean the primary filter/water separator of debris. Refer to the Operation and Maintenance Manual for details.
If the fuel pressure is still low, check the operation of the fuel pressure regulating valve. Also, check for the proper operation of the fuel transfer pump. Refer to Systems Operation/Testing and Adjusting for test information.
- Perform the "Injector Solenoid Test" on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM.
- Perform the "Cylinder Cutout Test" on Cat ET in order to determine the performance of each cylinder. Refer to Troubleshooting, "Injector Solenoid - Test" for the proper procedure.
Restriction in the Air Inlet and Exhaust System
- Check the air filter restriction indicator, if equipped. Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual.
- Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/Testing and Adjusting.