3126B Petroleum Engine Caterpillar

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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.

Probable Causes

• Air inlet and exhaust system

• Engine speed/timing

• Atmospheric pressure sensor

• Turbocharger outlet pressure sensor

• "Fuel Position" and/or "FRC Fuel Limit"

• Personality module

• Fuel quality

• Valve adjustment

Recommended Actions

Air Inlet and Exhaust System

1. Check for an air filter restriction. If necessary, service the air filter element.

2. Check for the correct operation of the turbocharger. Refer to Systems Operation/Testing and Adjusting, "Turbocharger - Test" for more information.

3. Check for air inlet restrictions and/or leaks. Check for exhaust restrictions. Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System - Inspect" for more information.

Engine Speed/Timing

1. Check the calibration of the engine speed/timing sensors. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

2. Remove the engine's front cover. Ensure that crankshaft/camshaft timing is oriented so that the timing marks are in alignment. Refer to Disassembly and Assembly for the corresponding procedures.

Atmospheric Pressure Sensor

Check the atmospheric pressure sensor for dirt and/or for debris. Remove any dirt and/or debris that is present. The correct reading for the atmospheric pressure is between 50 kPa (7.25 psi) and 100 kPa (14.5 psi).

Boost Pressure Sensor, "Fuel Position", and/or "FRC Fuel Limit"

1. Monitor the status of "Fuel Position", "Rated Fuel Limit", and "FRC Fuel Limit" on Caterpillar Electronic Technician (ET) while the engine is operating under full load. These parameters should reflect the information below.
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   Table 1

   "Fuel Position" = "Rated Fuel Limit" AND "Fuel Position" < "FRC Fuel Limit"

   If "Fuel Position" equals "Rated Fuel Limit" and "Fuel Position" is less than "FRC Fuel Limit", the electronics are operating correctly. Otherwise, proceed with the Step 2.

2. Monitor the status of "Boost Pressure" and "Atmospheric Pressure" for normal operation on Cat ET. When the engine is not running, "Boost Pressure" should be 0 kPa (0 psi).

   Note: A problem with the FRC will only cause black smoke during acceleration. A problem with the FRC will not cause black smoke during steady state operation.

Personality Module

Verify that the correct personality module is installed. Refer to Troubleshooting, "Flash Programming" for more information.

Fuel Quality

Check fuel quality. If necessary, replace the fuel with a higher cetane fuel.

Cold weather adversely affects the characteristics of the fuel. Refer to Special Publication, SEBU6251, "Caterpillar Commercial Diesel Engine Fluids Recommendations" for information on improving the characteristics of the fuel during cold weather operation.

Valve Adjustment

Check the valve adjustment. Refer to Systems Operation/Testing and Adjusting, "Engine Valve Lash - Inspect/Adjust".