BOSS 9J3473 - Caterpillar

Probable Causes
Fuel
Electrical connectors
Injector solenoids
Engine lubrication
Valve lash
Valve train components
Connecting rod bearingsRecommended Actions
Low Quality Fuel
Refer to Operation and Maintenance Manual for information on the proper 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.Electrical Connectors
Check for the correct installation of the J1/P1 and the J2/P2 connectors that are for the Electronic Control Module (ECM). Check for correct installation of the fuel injector connectors. Repair connectors that are suspect or replace connectors that are suspect. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Injector Solenoids
Use Caterpillar Electronic Technician (ET) to determine if any diagnostic codes for the injector solenoids are active or logged. Perform the "Injector Solenoid Test". Observe that the injector solenoids are being energized on Cat ET. Perform the "Cylinder Cutout Test". Isolate misfiring cylinders. Refer to Troubleshooting, "Injector Solenoid - Test".Engine Lubrication
Check for proper lubrication of the valve components. Check for sufficient lubrication between the injector tappets and the rocker arms. Check for blocked oil passages. Oil passages must be clean. Clean any oil passages that are questionable.Valve Lash
Check the valve lash. Refer to Troubleshooting, "Valve Lash Is Excessive".Valve Train Components
Check for damage to valve train components. Remove the valve cover from the suspect cylinder(s). Check the following items for damage: camshaft, valve rotocoil, valve springs, camshaft followers, rocker shaft, bridges and injectors.
Check for valves that do not move freely. Remove the cylinder head and inspect the valves. Replace any damaged parts. If damage has occurred, ensure that the following components are free of contamination: cylinder liner, piston and exhaust system. Replace any damaged parts.Connecting Rod Bearings
Inspect the connecting rod bearings and the bearing surfaces (journals) on the crankshaft. Check the piston pin for excessive wear. Replace any damaged parts.