16755Q 1 Mercruiser SEAL

Probable Causes
Diagnostic codes
Event codes
Air inlet and exhaust restrictions
Throttle signal
Power supply for the Electronic Control Module (ECM)
Injection actuation pressure
Fuel supplyRecommended Actions
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.Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect Caterpillar Electronic Technician (ET) and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure.Air Inlet and Exhaust Restrictions
Ensure that the turbocharger is operating correctly. Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side).Check the air filter restriction indicator, if equipped. Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual.Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/Testing and Adjusting.Throttle Signal
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. Refer to Troubleshooting, "Speed Control - Test".ECM Power Supply
Inspect the circuit between the ECM and the batteries. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the components in the circuit. Refer to Troubleshooting, "Electrical Power Supply - Test" for more information.
Inspect the circuit between the ECM and the keyswitch. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the components in the circuit. Refer to Troubleshooting, "Electrical Power Supply - Test" for more information.Injection Actuation Pressure
Check the engine oil level. Engine oil supplies the injection actuation pressure circuit. The engine oil must be kept at the proper level for fuel injection.
If service has recently been performed on the engine, air may be present in the injection actuation pressure circuit. Allow the engine to fully warm up and operate the engine under load in order to purge the air from the injection actuation pressure circuit.
Perform the "Injection Actuation Pressure Test " in Cat ET. Check the injection actuation pressure. If necessary, check the operation of the injection actuation pressure control valve. Refer to Troubleshooting, "Injection Actuation Pressure Control Valve - Test".Fuel Supply
Visually check the fuel level. Do not rely on the fuel gauge only. If necessary, add fuel. If the engine has been run out of fuel, it will be necessary to purge the air from the fuel system. Refer to the Operation and Maintenance Manual for more information.
Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
Check the fuel lines for the following problems: restrictions, collapsed lines, pinched lines and loose connections. If problems are found with the fuel lines, repair the lines and/or replace the lines.
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: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Systems Operation/Testing and Adjusting.
Check the fuel tank for foreign objects which may block the fuel supply.
Check the fuel filters.
Check the fuel quality. Make sure that the fuel meets the requirements of Special Publication, SEBU6250, "Caterpillar Machine Fluids Recommendations ".
Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.