BEARING 2941785 - Caterpillar

Probable Causes
Gas fuel quality
Excessive load
Excessive inlet air pressure
High inlet air temperature
Incorrect timing calibration
Faulty circuit for the detonation sensor
Excessive deposits in the combustion chamber
Cylinder misfire
Valve lash
Low inlet manifold air temperature
Incorrect air/fuel ratioRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for Diagnostic Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Monitor the diagnostic codes on Cat ET. Determine if a code is active or logged.
Note: Wait at least 30 seconds in order for diagnostic codes to become active.
   
Codes
   
Result: A diagnostic code is active or logged.
Repair: Troubleshoot any codes before continuing with this procedure.
Verify that the repair eliminated the problem.
Result: A diagnostic code is not active or logged.
Proceed to Test Step 2.
   
2. Check for Gas Fuel Quality
A. Obtain a gas sample. Refer to Operation and Maintenance Manual for directions using Gas Engine Rating Program (GERP) to determine the Methane Number.
   
Methane Number
   
Result: Methane Number is NOT OK.
Repair: Refer to Application and Installation Guide, LEBW4977, "Gaseous Fuels" to make sure the proper quality and filtration is being used. Verify that the repair eliminated the problem.
Result: Methane Number is OK.
Proceed to Test Step 3.
   
3. Check for Excessive Load
A. Ensure that the load is not excessive. If necessary, disengage the driven equipment and test the engine.
   
Excessive Load
   
Result: The engine has an excessive load.
Repair: Repair or replace any necessary components.
Verify that the repair eliminated the problem.
Result: No excessive load on the engine.
Proceed to Test Step 4.
   
4. Check for Excessive Inlet Air Pressure
Note: The calculated engine load will increase as the inlet air pressure increases.
A. Measure the inlet air pressure during engine operation with a load. For specific data on the engine, refer to the performance data sheet for the engine.
   
Air Pressure
   
Result: The code was logged during a heavy load.
Repair: Reduce the load on the engine.
Verify that the repair eliminated the problem.
Result: The code was not logged during a heavy load.
Proceed to Test Step 5.
   
5. Check for High Inlet Air Temperature
A. Check the inlet air temperature.
B. Check for a restriction to the air flow through the aftercooler.
   
Air Temperature
   
Result: The inlet air temperature is high.
Repair: Refer to Troubleshooting, "Inlet Air Temperature Is High". Verify that the repair eliminated the problem.
Result: The inlet air temperature is not high.
Continue with Test Step 5.
Result: The engine aftercooler was obstructed.
Repair: Remove the obstruction from the aftercooler. Verify that the repair eliminated the problem.
Result: The engine aftercooler was not obstructed.
Proceed to Test Step 6.
   
6. Incorrect Timing Calibration
A. Perform a timing calibration on the engine.
Note: Only perform this procedure if work on the engine may have affected the engine timing. Also, perform this procedure if the engine speed/timing sensor has not been calibrated
   
Timing calibration
   
Result: The timing calibration is not correct.
Repair: Refer to Troubleshooting, "Timing - Calibrate". Verify that the repair eliminated the