AXLE AR-FRONT 8I3112 - Caterpillar

Probable Causes
Active codes and logged codes
Electrical connections
Fuel injection
Fuel quality
Proper lubrication
Isolate the source of the noise.
Valve train components
Pistons and connecting rods
CrankshaftRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Active Codes and Logged Codes
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
Codes
Result: There are active codes.
Repair: Troubleshoot any active codes before continuing with this procedure.
Result: There are no active codes.
Proceed to Test Step 2.
2. Electrical Connections
A. Check for the correct installation of the ECM J1/P1 and the J2/P2 connectors. Check for correct installation of the fuel injector connectors.
Connectors
Result: There are suspect connectors.
Repair: Repair connectors that are suspect or replace connectors that are suspect.
Perform the "Wiggle Test" on the electronic service tool.
Result: There are no suspect connectors.
Proceed to Test Step 3.
3. Fuel Injection
A. Perform the "Fuel System Verification Test" in the "Diagnostic Tests" under the "Diagnostics" menu.
Fuel system verification test
Result: The test was successful.
Proceed to Test Step 4.
Result: The test was not successful.
Repair: Diagnose and repair the fault.
Reset all active codes and clear all logged codes.
Verify that the repair eliminated the fault.
4. Fuel Quality
A. Refer to Operation and Maintenance Manual for information on the correct characteristics of the fuel for the engine. If necessary, obtain a fuel analysis in order to confirm that the correct fuel is being used for the engine. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test" for the correct procedure.
Fuel
Result: The fuel quality is OK.
Proceed to Test Step 5.
Result: The fuel quality is not OK.
Repair: Replace the fuel. Verify that the repair eliminated the fault.
5. Lubrication
A. Check for sufficient lubrication of the valve components.
B. Check for blocked oil passages. Oil passages must be clean. Clean any oil passages that are suspect. Refer to the Disassembly and Assembly for additional information.
C. Inspect the engine oil filters for ferrous material.
D. Obtain an oil analysis.
Note: The analysis will contribute to a better understanding of oil contamination and the origin of the contamination.
Lubrication
Result: The oil passages are not blocked and the engine has sufficient lubrication.
Proceed to Test Step 6.
Result: The oil passages are blocked or the engine does not have sufficient lubrication.
Repair: Make the necessary repairs, Verify that the repair eliminated the fault.
6. Isolate the Source of the Noise
A. If the source of the noise is an engine accessory, remove and inspect the suspect item.
Engine accessory
Result An engine accessory is the source of the noise.
Repair: Repair and/or replace the engine accessory, if necessary.
Result An engine accessory is not the source of the noise.
Proceed to Test Step 7.
7. Valve Train Components
A. Check the valve lash. Refer to Troubleshooting, "Valve Lash Is Excessive".
B. Check for damage to valve train components. Remove the valve cover from the suspect cylinders. Check the following items for damage:
Camshaft
Valve springs
Camshaft followers
Rocker shaft
Valve bridges
Pushrods
Injectors
Refer to Disassembly and Assembly for additional information.
C. Check for