F481061-2 Force CARBURETOR COMPLETE (WB-21C)

Probable Causes
Diagnostic codes
Programmable parameters
Electrical connectors
Cold mode
Fuel injectors
Fuel supply
Air inlet and exhaust systemRecommended Actions
Note: If the symptom only occurs under certain operating conditions (high idle, full load, engine operating temperature, etc), test the engine under those conditions. Troubleshooting the symptom under other conditions can give misleading results.
Table 1
Troubleshooting Test Steps Values Results
1. Check for Active Diagnostic Codes
Codes
Result: There are no active diagnostic codes.
Proceed to Test Step 2.
Result: There are active diagnostic codes.
Repair: Troubleshoot any active codes before continuing with this procedure.
If the problem is not resolved, proceed to Test Step 2.
2. Check the Programmable Parameters
A. Check the following parameters on Cat ™ ET:
• Throttle Position Sensor
Programmable Parameters
Result: The programmable parameters are correct.
Proceed to Test Step 2.
Result: The programmable parameters are incorrect.
Repair: Determine the type of throttle that is used in the application. Program the parameters to match the type of throttle that is used. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test" for more information.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Electrical Connectors
A. Check the connectors for the Electronic Control Module (ECM) and the connectors for the unit injectors for correct installation. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Electrical Connectors
Result: The electrical connectors are OK.
Proceed to Test Step 4.
Result: The electrical connectors are worn or damaged.
Repair: Repair or replace the electrical connectors.
If the problem is not resolved, proceed to Test Step 4.
4. Check for Cold Mode Operation
A. Use Cat™ ET to verify that the engine has exited cold mode. Cold mode operation may cause the engine to run rough and the engine power may be limited.
Cold Mode
Result: The engine is not in cold mode.
Proceed to Test Step 5.
Result: The engine is in cold mode.
Repair: Take the engine out of cold mode.
If the problem is not resolved, proceed to Test Step 5.
5. Check the Fuel Injectors
A. Use Cat ET to determine if there are any active diagnostic codes for the unit injectors.
B. Perform the injector solenoid test on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM. Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for the proper procedure.
C. 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.
Fuel Injectors
Result: The fuel injectors are OK.
Proceed to Test Step 5.
Result: The fuel injectors are NOT OK.
Repair: Replace the fuel injectors.
If the problem is not resolved, proceed to Test Step 6.
6. Check the Fuel Supply
A. 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.
B. 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: 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.
Fuel Supply
Result: The fuel supply is OK.
Proceed to Test Step 7.
Result: The fuel supply is NOT OK.
Repair: Repair or replace any worn or damaged components.
Relieve any blockages in the fuel supply.
If the problem is not resolved, proceed to Test Step 7.
7. Check the Air Inlet and Exhaust System
A. 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 for leaks. Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System". Check the air inlet and exhaust system for restrictions and/or for leaks. Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System".
Air Inlet and Exhaust System
Result: The air inlet and exhaust system is OK.
Return the unit to service.
Result: The air inlet and exhaust system is NOT OK.
Repair: Repair or replace any worn or damaged components.
Remove any blockages or plugged filters.