0439510 JOHNSON CARBURETOR ASSY., Lower

Recommended Actions
Active Engine Derate
Use Caterpillar Electronic Technician (ET) to check for logged engine derates and/or active engine derates. A derate status flag will appear on Cat ET if an engine derate is active. The engine may be derated due to one of the following conditions: high altitude, dirty air filters and other factors.Cold Mode
Use Cat ET to verify that the engine has exited cold mode. Cold mode operation may slow throttle response.Personality Module (Flash File)
Verify that the correct personality module (flash file) is installed.Throttle Switch
Monitor the throttle switch on Cat ET. Verify that the throttle switch is operating correctly. Refer to Troubleshooting, "Throttle Switch Circuit - Test" for the proper troubleshooting procedure.Decelerator Pedal
Monitor the decelerator pedal on Cat ET. Verify that the decelerator pedal is operating properly. Refer to Troubleshooting, "Decelerator Position Sensor Circuit - Test" for the proper troubleshooting procedure.Electrical Connectors
Check for correct installation of the J1/P1 and J2/P2 connectors and the unit injector connectors for the Electronic Control Module (ECM). Refer to Troubleshooting, "Electrical Connectors - Inspect".Unit Injectors
Use Cat ET to determine if there are any active diagnostic codes for the 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
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 Testing and Adjusting, "Air Inlet and Exhaust System".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 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. Refer to Testing and Adjusting 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.
Purge air from the low pressure fuel supply circuit. Refer to Operation and Maintenance Manual, "Fuel System - Prime" for the correct procedure.
Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Refer to Special Instruction, SEBD0717, "Diesel Fuels And Your Engine".
Check the fuel pressure after the fuel filter while the engine is being cranked. Refer to Testing and Adjusting 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. Refer to Testing and Adjusting for more information.