89774 Mercury PLUG

Probable Causes
Diagnostic codes
Event codes
High turbocharger inlet temperature
High inlet manifold air temperature
Air inlet and exhaust restrictions
Throttle signal
Power supply for the Electronic Control Module (ECM)
Low-Pressure fuel systemRecommended 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.
Table 1
Troubleshooting Test Steps     Values     Results    
1. Diagnostic Codes and Event Codes
A. Connect Caterpillar Electronic Technician (ET) and check for active codes, logged codes and/or derates. .Refer to Troubleshooting, "Electronic Service Tools", if necessary.    
Codes    
Result: An active, logged codes, and/or derate is present.
Troubleshoot any codes before continuing with the test.
An active or logged code is not present.
Proceed to Test Step 2.    
2. Air Inlet and Exhaust Restrictions
A. Ensure that the turbocharger is operating correctly. Periodic inspection and cleaning is recommended for the turbocharger compressor housing.
B. Check the air filter restriction indicator, if equipped.
C. Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/ Testing and Adjusting.    
Restrictions
or leaks    
Result: The turbocharger is NOT operating properly.
Make the necessary repairs. Verify that the problem is resolved.
Result: The turbocharger is operating properly.
Proceed to Test Step 3.    
3. Throttle Signal
A. Monitor the status for "Throttle Position" on Cat ET.
B. 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".    
Throttle signal    
Result: The throttle position signal is NOT OK.
Determine the fault and repair.
Result: The throttle position signal is OK.
Proceed to Test Step 6.    
4. ECM Power Supply
A. Inspect the circuit between the ECM and the batteries. Refer to the Electrical System Schematic Inspect the wires, connectors, and the components in the circuit. Refer to Troubleshooting, "Electrical Power Supply - Test" for more information.
B. Inspect the circuit between the ECM and the keyswitch. Refer to Electrical System Schematic. Inspect the wire, connectors, and components in the circuit. Refer to Troubleshooting, "Electrical Power Supply - Test" for more information.    
Power Supply    
Result: The circuit between the ECM and the batteries is OK.
Continue with this Test Step.
The circuit between the ECM and the batteries is NOT OK.
Make the necessary repairs. Verify that the problem is resolved.
Result: The circuit between the ECM and the keyswitch is OK.
Proceed to Test Step 6.
Result: The circuit between the ECM and the keyswitch is NOT OK.
Make the necessary repairs. Verify that the problem is resolved.    
5. Check the Low- Pressure Fuel System
A. 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, air must be purged from the fuel system.
B. Visually inspect the fuel system. Refer to System Operation/Testing and Adjusting, "Fuel System - Inspect" for more information.
C. Check the fuel tank for foreign objects which can block the fuel supply.    
Fuel system    
Result: The fuel system is OK.
Proceed to Test Step 6.
The fuel system is NOT OK.
Make the necessary repairs. Verify that the problem is resolved.    
6. Fuel Quality
A. Ensure that the fuel meets the requirements of Special Publication, "Caterpillar Machine Fluids Recommendations".
Cold weather adversely affects the characteristics of the fuel. Refer to Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation.    
Fuel quality    
Result: The fuel quality is OK.
Result: The fuel quality is NOT OK.
Drain the fuel, and replace the fuel.