C8.7 and C12.9 Marine Engines Caterpillar

Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. Check Caterpillar Electronic Technician (ET) for any associated codes that are listed in Table 1. Troubleshoot any active codes before continuing with this procedure.

Probable Causes

• Codes

• Parameters

• Throttle Signal

• Air Inlet and Exhaust System

• Fuel System

• Intake manifold pressure sensor

• Flash file

• Valve Lash

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load, and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.

Table 1

Troubleshooting Test Steps	Values	Results
1. Engine Derate or Active Codes A. Certain diagnostic and/or event codes can cause poor performance.	Engine Derate or Active Codes	Result: Active diagnostic codes are present Troubleshoot the active codes Result: Active diagnostic codes are NOT present Proceed to Test Step 2.
2. Incorrect Parameters A. Use Cat ET to verify that the correct parameters are being used. Refer to Troubleshooting, "Configuration Parameters" for additional information.	Parameters	Result: The parameters are correct. Proceed to Test Step 3. Result: The parameters are not correct. Input the correct parameters. Refer to Troubleshooting, "Configuration Parameters" for additional information.
3. Throttle Signal A. Monitor the status for "Throttle Position" on Cat ET. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed.	Throttle Signal	Result: The throttle signal is stable. Proceed to Test Step 4. Result: The throttle signal is not stable. Make the necessary repairs, Refer to the appropriate circuit test.
4. Check the Fuel System Refer to Systems Operation/Testing and Adjusting, "Fuel System" for additional information. A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. B. Ensure that the vent in the fuel cap is not filled with debris. C. Ensure that the fuel supply valve (if equipped) is in the full OPEN position. D. Inspect the fuel system. Refer to Systems Operation/Testing and Adjusting, "Fuel System - Inspect" for additional information. E. Check for the proper operation of the fuel transfer pump. Refer to Systems Operation/Testing and Adjusting, "Fuel System" for test information. F. Perform the “Injector Solenoid Test” on Cat ET to determine if all the injector solenoids are being energized by the ECM. G. Perform the “Cylinder Cutout Test” on Cat ET to determine the performance of each cylinder. Refer to Troubleshooting, "Injector Solenoid - Test" for the proper procedure.	Fuel system	Result: The fuel pressure is OK. Proceed to Test Step 6. Result: The fuel pressure is not OK. Replace the fuel filters. Clean the primary filter/water separator of debris. Refer to the Operation and Maintenance Manual for details.
4. Fuel Quality F. Check fuel quality. Refer to Systems Operation/Testing and Adjusting, "Fuel Quality - Test" for the proper procedure. Cold weather adversely affects the characteristics of the fuel. Refer to the engines Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation. Cold mode (if applicable) is activated whenever the engine coolant temperature falls below a predetermined value. Monitor the status screen on Cat ET to verify that the engine has exited cold mode. Observe the reading for coolant temperature on the Cat ET.	Fuel Quality	Result: The fuel quality is OK. Proceed to Test Step 5. Result: The fuel quality is NOT OK. Drain the fuel, and replace the fuel.
5. Electrical Connectors A. Check for correct installation of J1/P1 and J2/P2 ECM connectors and the unit injector connectors at the valve cover. Refer to Troubleshooting, "Electrical Connectors - Inspect".	Connectors	Result: Electrical connectors are in proper working condition. Proceed to Test Step 7. Result: Electrical connectors are not in proper working condition Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.
6. Valve Lash A. Check the valve lash. The valve lash can affect the performance of the engine.	Valve lash	Result: The valve lash is not set correctly. Set the valve lash. Refer to Testing and Adjusting, "Engine Valve Lash - Inspect/Adjust" for the correct procedure.

Table 2

Troubleshooting Test Steps	Values	Results
7. Intake Manifold Pressure Sensor A. Monitor the status of “Fuel Position”, “Rated Fuel Limit”, and “FRC Fuel Limit” on Cat ET while the engine is operating under full load. These parameters should reflect information that is listed in Illustration 1. B. Monitor the status of “Intake Manifold Pressure” on Cat ET, while the engine is not running. C. Check the status of “Atmospheric Pressure” for normal operation, If the application is installed with an atmospheric pressure sensor.	0 kpa (0 psi)	Result: If "Fuel Position" equals "Rated Fuel Limit" and "Fuel Position" is less than "FRC Fuel Limit", the electronics are operating properly. Result: The electronics are not working properly. Continue with this Test Step
8. Restriction in the Air Inlet and Exhaust System A. Observe the check engine lamp. Check for an air filter restriction indicator. Replace any plugged air filters. Refer to the Operation and Maintenance Manual. B. Check the air inlet and exhaust system for restrictions and/or leaks.	Restrictions	Result: There are no restrictions in the air inlet or exhaust system. Result: There are restrictions in the air inlet or exhaust system. Make the necessary repairs, Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System - Inspect" for additional information.

Complete the procedure in the order in which the steps are listed.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).