EXTENSION AS 4420846 - Caterpillar

Probable Causes
Programmable parameters
Diagnostic codes
Event codes
Starting aids
Throttle signal
Electrical connectors
Unit injectors
Injection actuation pressure
Fuel supply
Boost pressure sensor
Air inlet and exhaust systemRecommended 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.Programmable Parameters
Verify that the complaint is not due to a parameter that is incorrectly programmed. Connect the electronic service tool and verify that the parameters are programmed correctly.Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the electronic service tool and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.Starting Aids
Cold Mode
Use the electronic service tool to verify that the engine has exited cold mode. If the engine is operating in cold mode, an indicator will be displayed on the top of any of the status screens on the electronic service tool. Cold mode operation may slow throttle response.Air Inlet Heater
Ensure that the air inlet heater is operating correctly. For additional information on the air inlet heater, refer to Troubleshooting, "Air Inlet Heater Circuit - Test".Throttle Signal
Connect the electronic service tool to the service tool connector. Turn the keyswitch to the ON position. The engine should be off.Monitor the throttle position from low idle to full throttle. The duty cycle should be between 5 and 10 percent at low idle. The duty cycle will increase to 90 to 95 percent at full throttle. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for additional information if the change in the throttle position is erratic or if the change in the throttle position is out of the specified range.Electrical Connectors
Check the J1/P1 Electronic Control Module (ECM) connector, the J2/P2 ECM connector, the J300/P300 unit injector connector, the connectors for the throttle position sensor, and the associated wiring for damage, for abrasion, for corrosion, or for incorrect attachment. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.Unit Injectors
Perform the injector solenoid test on the electronic service tool in order to determine if all of the injector solenoids are being energized by the ECM.
Perform the cylinder cutout test on the electronic service tool in order to identify any injectors that might be misfiring. Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for the proper procedure.Injection Actuation Pressure
Check the engine oil level. Engine oil is used to activate the high pressure hydraulic pump.
Ensure that the engine oil meets the recommendations. Refer to Operation and Maintenance Manual for additional information.
Crank the engine and monitor the injection actuation pressure and the output of the injection actuation pressure control valve. The high pressure oil system is operating properly if the pressure output is a minimum of 6 MPa (870 psi).Fuel Supply
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