LOCK 9S0723 - Caterpillar

Probable Causes
Excessive load
Incorrect base timing
Fuel supply
Ignition system
Incorrect air/fuel ratio
Incorrect governor adjustment
Binding of the throttle actuator
Incorrect valve lash
Cylinder head and related componentsRecommended Repairs
Table 1
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: An associated code is NOT present.
Proceed to Test Step 2.
2. 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: No excessive load on the engine.
Proceed to Test Step 3.
Result: The engine has an excessive load.
Repair: Remedy the cause of the excessive load.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Fuel Supply
A. Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel line is sufficient. Inspect the fuel system for leaks.
The following conditions can cause the engine to malfunction:
- Low fuel pressure
- High fuel pressure
- Poor fuel quality
B. Make sure that the fuel pressure is correct. When possible, interview the operator to determine if fuel quality is in question. Try to determine if the source of the fuel was changed.
Inspect the fuel system components:
- Fuel filter
- Gas pressure regulator
- Gas shutoff valve
- Fuel metering valve
- LISK valve
Fuel
Result: The fuel supply is OK.
Proceed to Test Step 4.
Result: A faulty component was identified.
Repair: Repair or replace the faulty component.
If the problem is not resolved, proceed to Test Step 4.
4. Check the Ignition System
A. Ensure that current parts are used for the following components:
- Transformers
- Extenders
- Spark plugs
Inspect the ignition system for the following conditions:
1. Check the connection between the ignition transformer and the extender. A loose connection can cause arcing and misfires.
2. Check the connection between the extender and the spark plug for a loose connection or for pin holes that are caused by arcing. Both conditions can cause misfires.
3. Check the extender for corrosion on the spring. Corrosion may cause arcing through the extender.
4. Check for corrosion on the terminal of the spark plug and check for wear on the electrode. Both conditions can cause misfires.
Excessive moisture can cause misfire.
Maintain the spark plug according to the engine Operation and Maintenance Manual.
Ignition System
Result: The Ignition System is OK.
Proceed to Test Step 5.
Result: A faulty component was identified.
Repair: Repair or replace the faulty component.
If the problem is not resolved, proceed to Test Step 5.
5. Check the Air/Fuel Ratio
A. Verify that the exhaust emissions are correct. Refer to Systems Operation/Testing and Adjusting, "Air/Fuel Ratio Control - Adjust".
Air/Fuel Ratio
Result: The Air/Fuel Ratio is correct.
Proceed to Test Step 6.
Result: The Air/Fuel Ratio is NOT correct.
Repair: Correct the Air/Fuel Ratio.
If the problem is not resolved, proceed to Test Step 6.
6. Check the Governor Adjustment
A. The governor parameters must be programmed with the values that provide stable operation. Refer to Systems Operation/Testing and Adjusting, "Engine Governing - Adjust".
Governor Adjustment
Result: The