Note: If this problem occurs only under load, refer to Troubleshooting, "Low Power/Poor or No Response to Throttle".
- Active engine derate
- Cold mode
- Throttle signal
- Boost pressure sensor
- Atmospheric pressure sensor
- Fuel supply
- Air inlet and exhaust system
- Accessory equipment
If this application supports engine derates, use AVSpare Electronic Technician (ET) to check for logged derates. Refer to Troubleshooting, "Troubleshooting with an Event Code" for the specific events that are applicable to this application. A status flag will appear on Cat ET if a derate is active. The engine speed might be limited due to one of the following conditions: high altitude, dirty air filters and other factors.
Use Cat ET to verify that the engine has exited cold mode. A status flag will appear if the engine is operating in cold mode. This may limit engine speed.
Monitor Cat ET in order to verify that full throttle can be achieved. Refer to Troubleshooting, "Throttle Switch Circuit - Test".
- Monitor the status of "Fuel Position", "Rated Fuel Limit", and "FRC Fuel Limit" on Cat ET while the engine is operating under full load. These parameters should reflect the information below.
Table 1 "Fuel Position" = "Rated Fuel Limit" and "Fuel Position" < "FRC Fuel Limit"
If "Fuel Position" equals "Rated Fuel Limit" and "Fuel Position" is less than "FRC Fuel Limit", the electronics are operating correctly. Otherwise, proceed with the next Step.
- Monitor the status of "Boost Pressure" and "Atmospheric Pressure" for normal operation on Cat ET. When the engine is not running, the correct "Boost Pressure" is
0 kPa (0 psi).
- Verify that the boost pressure sensor is operating properly.
- 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.
- Check the fuel tank for 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: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Systems Operation/Testing and Adjusting, "Air in Fuel - Test" for more information.
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.
- 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.
- Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. 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.
- Observe the check engine lamp. Check for an air filter restriction indicator. 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, "Air Inlet and Exhaust System".
Check all accessory equipment for problems that may create excessive load on the engine. Repair any damaged components or replace any damaged components.