SEAL-O-RING 4374425 - Caterpillar

Probable Causes
Diagnostic codes
Event codes
Starting aids
Personality module (flash file)
Throttle signal
Electrical connectors
Unit injectors
Turbocharger outlet pressure sensor
Air inlet and exhaust system
Fuel supplyRecommended Actions
Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (Cat ET) and check for active codes and/or logged codes. Troubleshoot any codes that are present before continuing with this procedure.Starting Aids
Cold Mode
Use Cat ET 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 Cat ET. Cold mode operation may slow throttle response.Air Inlet Heater (If Equipped)
Ensure that the air inlet heater is programmed to "On". Ensure that the air inlet heater is functioning properly. Refer to Troubleshooting, "Air Inlet Heater Circuit - Test" for additional information.Oil Grade Plugs (If Equipped)
Ensure that the correct oil grade plug is installed. Refer to Operation and Maintenance Manual, "Engine Oil and Filter - Change" for additional information.Personality Module (Flash File)
Verify that the correct personality module (flash file) is installed.Throttle Signal
Monitor the throttle signal on Cat ET. Verify that the throttle is operating correctly. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for additional information.Electrical Connectors
Check for correct installation of the J1/P1 and J2/P2 ECM connectors and the unit injector connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.Unit Injectors
Perform the Injector Solenoid Test on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM.
Perform the Cylinder Cutout Test on Cat ET in order to identify any injectors that might be misfiring. Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for the proper procedure.Turbocharger Outlet Pressure Sensor
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, "Boost Pressure" should be 0 kPa (0 psi).Air Inlet and Exhaust System
Check for an air filter restriction. Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual for additional information.
Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Testing and Adjusting, "Air Inlet and Exhaust System" for additional information.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 objects which may block the fuel supply.
Check for air in the low pressure fuel supply system if any of the following procedures have been performed:
Replacement of the