3512B Marine Auxiliary Engine Caterpillar

• Engine shutdown

• Position sensors

• Faulty electrical connections

• Electrical power supply to the Electronic Control Module (ECM)

• Circuit breakers

• Engine speed/timing sensor(s)

• Fuel supply

Perform the following checks:

1. Connect the Caterpillar Electronic Technician (ET) and check for engine shutdowns. Determine the reason for the shutdown. After correcting the problem, cycle power to the ECM for at least 15 seconds before you try to restart the engine.

2. Position sensors are located at each of the air shutoff valves. The position sensors are located just below the solenoid for the air shutoff valve. In order to run the engine, these microswitches must be in the closed state.

3. Inspect the electrical connectors for proper installation. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

4. Check the Cat ET for the following logged diagnostic codes: 168-01 and 168-02. Follow the battery wires from the ECM back to the battery compartment. Refer to the Electrical System Schematic. Inspect the wires and the power relay. Check the power to the ECM and to the ground connections. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply".

5. The circuit breakers may have exceeded the trip point due to overheating. Check the circuit breakers. Reset the circuit breakers if the circuit breakers are tripped.

6. Check the Cat ET for the following logged diagnostic codes for the primary engine speed/timing sensor: 190-02, 190-03 and 190-08. If the engine is equipped with a secondary engine speed/timing sensor, check for the following logged diagnostic codes: 342-02, 342-03 and 342-08. Refer to the diagnostic functional test Troubleshooting, "Engine Speed/Timing Sensor".

7. Check fuel lines for the following problems: restrictions, collapse and pinched line Repair the lines and/or replace the lines. Refer to the Testing and Adjusting, "Fuel System Inspection".

   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 performing 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). Refer to Special Publication, SEBD0717, "Diesel Fuels And Your Engine". Check the fuel pressure while the engine is cranking. Check the fuel pressure at the filter. Refer to Testing and Adjusting, "Fuel Pressure" 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.