LOCK AS-CYLINDER 1268510 - Caterpillar

Probable Causes
Fuel supply
Electrical connectors or power supply
Engine speed/timing sensor
Ignition system
Excessive loadRecommended Actions
Fuel Supply
Verify that the fuel pressure is correct. When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel has been changed.Ensure that fuel is supplied at a sufficient pressure that is stable. Check that the size of the fuel line is large enough to provide an adequate volume of fuel to the engine. Inspect the fuel system for leaks.The following conditions can affect starting:
Low fuel pressure
High fuel pressure
Poor fuel qualityInspect the following fuel system components:
Fuel filter
Gas pressure regulator
Gas shutoff valve
Fuel actuatorVerify that the system components are operating correctly.Repair suspect components. Replace the fuel filter, if necessary.Electrical Connectors or Power Supply
Inspect the power supply connections and the ground. Check the wiring harnesses and the connectors from the power supply to the power distribution box. Check the wiring harnesses and the connectors from the power distribution panel to the Electronic Control Module (ECM). Refer to Testing and Adjusting, "Electrical Connectors - Inspect".
Use Caterpillar Electronic Technician (ET) to check for an active 168-2 Electrical System Voltage erratic, intermittent, or incorrect. If this diagnostic code is logged, proceed to Troubleshooting, "Electrical Power Supply - Test".Speed/Timing Sensor
Ensure that the engine speed/timing sensor is installed correctly. Refer to Troubleshooting, "Speed/Timing - Test".Ignition System
Significant improvements have been made to the parts in the ignition system in order to reduce losses in the ignition system. Ensure that current parts are used for the following components:
Transformers
Spark plug wires
Spark plugsInspect the ignition system for the following conditions:
Check the connections between the ignition transformers and the spark plug wires. A loose connection can cause arcing and misfires.
Check the connections between the spark plug wires and the spark plugs for a loose connection or for pin holes that are caused by arcing. Both conditions can cause misfires.
Ensure that the correct transformers and spark plugs are installed on the engine. Inspect the spark plug wires for signs of pin holes and of electrical arcing. Check the spark plugs for fouling, correct gap adjustment, and moisture.
Check for corrosion on the terminal of the spark plug and check for wear on the electrode. Both conditions can cause misfires.Other losses or misfires are caused by shorts or excessive moisture.Maintain the spark plug according to the Operation and Maintenance Manual.Excessive Load
Ensure that the load that is on the engine is not excessive. Reduce the load. If necessary, disengage the driven equipment and test the engine.