Intermittent Low Power or Power Cutout
Note: Use this procedure only if the engine does not shut down completely.
Probable Causes
* Diagnostic codes
* Event codes
* Turbocharger
* Air inlet and exhaust restrictions
* Throttle signal
* Power supply for the Electronic Control Module (ECM)
* Fuel supply
Recommended Actions
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.
Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (ET) and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.
Turbocharger
Ensure that the turbocharger is operating correctly. Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side).
Air Inlet and Exhaust Restrictions
Check the air inlet system for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines.
Check for an air filter restriction. Replace plugged air filters and/or clean filters. Repair any leaks.
Throttle Signal
Monitor the status for "Throttle Position" on Cat ET. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed. Refer to the appropriate diagnostic test for your application:
* Troubleshooting, "Throttle Position Sensor Circuit - Test"
* Troubleshooting, "Throttle Switch Circuit - Test"
* Troubleshooting, "Speed Control - Test"
ECM Power Supply
1. Inspect the circuit between the ECM and the batteries. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the components in the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test" for more information.
2. Inspect the circuit between the ECM and the keyswitch. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the components in the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test" for more information.
Fuel Supply
1. Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
2. Check the fuel tank for foreign objects which may block the fuel supply.
3. 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: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. For more information, refer to Systems Operation/Testing and Adjusting, "Air in Fuel - Test".
4. Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
NOTICE
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
5. Check the fuel pressure after the fuel filter while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting, "Fuel System" for the correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve. Refer to Systems Operation/Testing and Adjusting for more information.
