3512B Marine Auxiliary Engine Caterpillar

• Leaking injector

• Air inlet restriction

• Leaking air system

• Incorrect calibration of the Engine Speed/Timing Sensor

• Rated Fuel Position

• Compartment Pressure Sensor

• Personality Module

• Fuel supply

• Fuel Injector Timing

Perform the following tests in order:

1. Perform the Cylinder Cutout Test. Use similar conditions for the test that were experienced during operation. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoids".

   1. Cut out the individual cylinder for 30 seconds to 1 minute. Verify that the smoke decreases.

2. Connect the Caterpillar Electronic Technician (ET). Check the reading for the compartment pressure. Check the reading for the engine air manifold pressure.

   1. Check air inlet and exhaust systems for restrictions and/or leaks. Remove any restrictions. Repair any leaks that are found.

3. Verify that the turbocharger has not failed. Refer to the Systems Operation.

   1. Replace plugged air filters, and/or clean the filters. Refer to Operation and Maintenance Manual.

   2. Verify proper operation of the engine air manifold pressure sensor and the compartment pressure sensor. Refer to the diagnostic functional test Troubleshooting, "Engine Sensor Open/Short Test".

4. Check the calibration of the Engine Speed/Timing Sensor. Refer to the calibration procedure Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

   1. Verify that the crankshaft and camshaft drive gears are set with the proper orientation. Refer to Disassembly and Assembly Manual.

5. Monitor the engine air manifold pressure and the compartment pressure with the Cat ET. Operate the engine under full load. Use the Cat ET in order to monitor the following values: engine air manifold pressure, Fuel Position and Rated Fuel Position. The Fuel Position should equal the Rated Fuel Position. Refer to Systems Operation, Testing and Adjusting.

6. Check the Compartment Pressure Sensor for dirt and/or debris. Remove the dirt and/or the debris. The Compartment pressure should be between 75 ± 25 kPa (11 ± 4 psi). Refer to the diagnostic functional test Troubleshooting, "Engine Sensor Open/Short Test".

7. Verify that the correct Personality Module is installed. Refer to the diagnostic procedure Troubleshooting, "Programming Parameters".

8. Check fuel lines for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines. Refer to the Systems Operation, "Fuel System".

   1. Check the fuel tank for foreign objects which may block the fuel supply. Check for air in the low pressure fuel supply system after you perform the following procedures:
      • Replacing the fuel filters

      • Working on the low pressure fuel supply circuit

      • Replacing fuel injectors

   2. Purge air from the low pressure fuel supply circuit with the hand priming pump and by cranking the engine in 30 second cycles. After you crank the engine, stop for two minutes. This will allow the starting motor to cool. Loosen the vent plug at the fuel return. The plug is located on the rear upper left side of the engine block. Hand prime the engine again if air in fuel continues. A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.

   3. Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Check the fuel pressure while the engine is cranking. Check the fuel pressure at the filter. Refer to the Specifications manual for correct pressure values. If the pressure is low, check for plugged fuel filters. If the fuel pressure is still low check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve. Check for a combustion problem.

9. Check the height of the fuel injector. Refer to the Systems Operation, "Unit Injector Adjustment".