Note: If this problem occurs under load, refer to the diagnostic procedure Troubleshooting, "Low Power/Poor Or No Response To Throttle".
Probable Causes
• Derated engine
• Cold mode
• Flash file
• Throttle signal
• Fuel supply
• Air inlet restriction
• Exhaust restriction
• Leaks in air system
• Valve adjustment
• Injectors
• Faulty accessory equipment
Recommended Actions
Derate
Connect Caterpillar Electronic Technician (ET) and check for an active derate event. A derate status flag will appear on Cat ET if an active engine derate is occurring. In order to view active events, go to the "Events" menu under "Diagnostics". Refer to Troubleshooting, "Troubleshooting with an Event Code" for the specific events for this application.
Cold Mode
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.
Flash File
Verify that the correct flash file has been installed.
Throttle Signal
Use Cat ET in order to monitor the status of the throttle. Observe the throttle position. Verify that the throttle position is smooth from low idle to high idle. The throttle position should reach 100 percent at high idle.
Fuel Supply
Check fuel lines for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines.
1. Check the fuel tank for foreign objects which may block the fuel supply. Check for air leaks in the suction line of the fuel pump. Prime the fuel system after you perform the following procedures:
o Replacing the fuel filters
o Working on the low pressure fuel supply circuit
o Replacing fuel injectors
2. 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.
3. Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. Refer to the Systems Operation/Testing and Adjusting manual 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.