856844 1 Mercury ELBOW

Probable Causes
Electronic Control Module (ECM)
Diagnostic codes
Event codesElectrical
Electrical connectors
Switches
Circuit breakersInlet Air
Air shutoffFuel
Fuel supplyRecommended Actions
Diagnostic Codes and/or Event Codes
Certain diagnostic codes and/or event codes may cause an engine shutdown. Connect Caterpillar Electronic Technician (ET) and check for active codes and for logged codes. Troubleshoot any codes that are present prior to continuing with this procedure.Electrical Connectors
Check for correct installation of the J1/P1 and J2/P2 connectors for the ECM. Also, thoroughly inspect the connectors for the engine speed/timing sensors. Refer to Troubleshooting, "Electrical Connectors".
Inspect the battery wires from the ECM to the battery compartment. Refer to the Schematic for specific wiring information. Check the unit injector connectors and associated wiring for damage, or for intermittent problems. Inspect the wires and connectors to all circuit protection for the engine. Check the power and ground connections to the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test".Switches
Check the keyswitch input to the ECM.Check any engine shutdown switches and associated wiring. If the application is equipped with an overspeed verify switch check the switch for correct operation. If equipped, verify that the crank without injection plug is installed securely.Circuit Breakers
Check the state of each of the circuit breakers. Reset the circuit breakers if the circuit breakers are tripped. Prior to returning the engine to service, determine the condition that caused the circuit breaker to trip. Make the necessary repairs.
Certain circuit protection devices may reset automatically. Verify if the application has any protection devices that reset automatically.
Air Shutoff
If equipped, verify that the air shutoffs are operating correctly.Fuel Supply
Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. If necessary, add fuel to the fuel tank. If the engine has been run out of fuel, it will be necessary to prime the fuel system. Refer to the Operation and Maintenance Manual, "Fuel System - Prime".
Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
Check the fuel tank for debris or foreign objects which may block the fuel supply.
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
Prime the fuel system if any of the following procedures have been performed:
Replacement of the fuel filters
Service on the low pressure fuel supply circuit
Replacement of unit injectorsNote: Check the fuel system for air.
Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual, "Fuel Quality - Test".
Check the filtered fuel pressure while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting, "Fuel System Pressure - Test". If the fuel pressure is low, replace the fuel filters. Clean the primary filter/water separator of debris. Refer to the Operation and Maintenance Manual, "Fuel System Primary Filter (Water Separtor) Element - Replace". If the fuel pressure is still low, check the operation of the fuel pressure regulating valve. Also, check for the proper operation of the fuel transfer pump. Refer to Systems Operation/Testing and Adjusting.