0305394 JOHNSON NUT

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.Derate Mode
Connect Caterpillar Electronic Technician (ET) and check for logged derate events. A status indicator for an active engine derate will appear on Cat ET if a derate is occurring. The engine speed might be limited due to one of the following possible causes: altitude, high exhaust temperatures, air filter restriction, high coolant temperature and crankcase pressure.Wastegate (if equipped)
Verify that the wastegate is operating correctly.Air Intake 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.
If air shutoff valves are installed, verify that the air shutoff valves are fully opened.
Check the air inlet and exhaust system for restrictions and/or leaks. Refer to the Systems Operation/Testing and Adjusting for information on the air inlet and exhaust system. Fuel Supply
Visually check the fuel level. Do not rely on the fuel gauge only. If necessary, add fuel. 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 more information.
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 and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
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.
Purge 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 injectorsNote: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.
Check the fuel tank for foreign objects which may block the fuel supply.
Check the fuel filters.
Check the diesel fuel for contamination. Refer to Systems Operation/Testing and Adjusting.
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. Injectors
Use Cat ET to determine if any active diagnostic codes are present. Perform the "Injector Solenoid Test" on Cat ET in order to determine if all of the injector solenoids are being energized by the Electronic Control Module (ECM).Perform the "Cylinder Cutout Test" on Cat ET in order to identify any injectors that might be misfiring. Refer to Troubleshooting, "Injector Solenoid - Test".Engine Speed/Timing Sensors
If the operation of any of the engine speed/timing sensors is suspect, refer to Troubleshooting, "Speed/Timing - Test" for information that is related to troubleshooting the engine speed/timing circuit.Electrical Connectors
Check for the correct installation of the J1/P1 and the J2/P2 ECM connectors. Check for correct installation of the fuel Injector connectors. Check the wiring harnesses for damage. Refer to Troubleshooting, "Electrical Connectors - Inspect".