3412 Generator Set Caterpillar

Acceleration Is Poor or Throttle Response Is Poor

Usage:

3412 DK6

Probable Causes

Fuel supply
Engine derate or active codes
Cold mode
Flash file
Throttle position signal
Electrical connectors
Air inlet and exhaust system
Rack controls

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.

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NOTICE

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.

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Table 1
Troubleshooting Test Steps	Value	Results
1. Check the Fuel Supply. A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. B. Check the fuel lines for the following problems: restrictions, collapsed lines, and pinched lines. C. Check the fuel tank for debris or foreign objects which may block the fuel supply. D. 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 Note : Check the fuel system for air. Refer to Systems Operation/Testing and Adjusting for information that is related to checking the fuel system for air. E. Check the fuel quality. F. Check the filtered fuel pressure while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting for the test procedure and for the correct pressure values.	Fuel Supply	Result : The fuel level in the tank is OK. Continue to Test Step 1-B. Result : The fuel level in the tank is NOT OK. Repair : If the engine has been run out of fuel, the fuel system will need to be purged. Refer to Operation and Maintenance Manual for the correct procedure. If necessary, add fuel to the fuel tank. Result : The fuel lines are OK. Proceed to Test Step 1-C. Result : The fuel lines are NOT OK. Repair :Repair the lines and/or replace the lines. Result : The fuel supply is OK. Proceed to Test Step 1-D. Result : The fuel supply is NOT OK. Repair : Remove the debris and/or foreign objects from the fuel supply. Result : The fuel system has been primed. Proceed to Test Step 1-E. Result : The fuel quality is OK. Proceed to Test Step 1-F. Result : The fuel quality is NOT OK. Repair : Refer to the engine Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation. Result : The fuel pressure is low. Repair : Replace the fuel filters. Clean the primary filter/water separator of debris. Refer to the Operation and Maintenance Manual for details. Result : The fuel pressure is still low. Repair : Check the operation of the fuel pressure regulating valve. Also, check for the proper operation of the fuel transfer pump. Refer to Systems Operation/Testing and Adjusting for test information. If the problem is not resolved, proceed to Test Step 2.

2. Check for Engine Derate or Active Diagnostic Codes. A. Some engine monitoring parameters that trigger an engine derate do not produce an event code. Connect Cat^® Electronic Technician (ET) in order to check for a derate of the engine. B. Certain diagnostic codes and may cause poor performance. Use Cat ET to check for active codes and for logged codes. Note : Although a sensor signal may be in the operational range of the sensor, the signal may not represent the actual reading. Use Cat ET to check that the pressures and the temperatures are fluctuating. Also check that the values are reasonable for the conditions that are present.	Engine Derate or Active Codes	Result : The engine is not in derate. Proceed to Test Step 2-B. Result : The engine is in derate. Repair : Check for any active associated codes. Troubleshoot any active codes that are present. Result : There are no diagnostic codes active. Proceed to Test Step 3. Result : There are diagnostic codes active. Repair : Troubleshoot any active codes that are present before continuing with this procedure. If the problem is not resolved, proceed to Test Step 3.
3. Check the Engine Cold Mode Operation. A.The Electronic Control Module (ECM) limits engine power during cold mode operation. The ECM may cut out certain engine cylinders. This will increase startability and this will reduce warm-up time. Cold mode is activated whenever the engine coolant temperature falls below a predetermined value. Cold mode remains active until the engine has warmed or a time limit is exceeded.	Cold Mode	Result : The cold mode is not activated. Proceed to Test Step 4. Result : The cold mode is activated. Repair : Check the engine coolant temperature. Troubleshoot any problem with the engine coolant temperature. If the problem is not resolved, proceed to Test Step 4.
4. Verify that the Latest Flash File is Installed on the ECM.	Flash file	Results : The latest flash file is installed. Proceed to Test Step 5. Result : The flash file on the ECM is not the latest available. Repair : Download and install the latest flash file. If the problem is not resolved, proceed to Test Step 5.
5. Monitor the Status for "Throttle Position" on Cat ET. A. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed.	Throttle Position	Result : The throttle position is correct. Proceed to Test Step 6. Result : The throttle position is NOT OK. Repair : Refer to the appropriate troubleshooting procedure for troubleshooting the throttle signal. If the problem is not resolved, proceed to Test Step 6.
6. Check for Correct Installation of the J14/P14 ECM Connector.	ECM Connector	Result : The ECM connector is OK. Proceed Test Step 7. Result : The ECM connector is NOT OK. Repair : Refer to Troubleshooting, "Electrical Connectors - Inspect". If the problem is not resolved, proceed to Test Step 7.
7. Check the Rack Controls. A. Check the rack solenoid for proper operation. B. Check the dynamic rack controls. C. Check the rack position sensor.	Rack Controls	Result : The rack solenoid is OK. Proceed to Test Step 7-B. Result : The rack solenoid is NOT OK. Repair : Refer to Troubleshooting, "Fuel Rack Solenoid - Test" for troubleshooting procedures. If the problem is not resolved, proceed to Test Step 7-B. Result : The dynamic rack controls are OK. Proceed to Test Step 7-C. Result : The dynamic rack controls are NOT OK. Repair : Refer to Troubleshooting, "Fuel Control - Test" in order to troubleshoot the dynamic rack controls. If the problem is not resolved, proceed to Test Step 7-C. Result : The rack position sensor is NOT OK. Result : Refer to Troubleshooting, "Sensor Signal (Analog, Active) - Test" for the troubleshooting procedure.