- Diagnostic codes and event codes
- Electronic Control Module (ECM)
- Starting aids (if applicable)
- Engine shutdown switches
- Engine speed/timing
- Unit injector
- Fuel supply
- Combustion
Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may prevent the engine from starting. Connect the 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.
Electronic Control Module (ECM)
If the ECM is not receiving battery voltage, the ECM will not operate. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test".
If cold ambient conditions exist, check operation of starting aids. Refer to the appropriate diagnostic functional test for troubleshooting information.
The engine shutdown switches must be in the RUN position in order to start the engine. Use Cat ET to verify the status of the shutdown switches. When an engine shutdown switch is used to shut down the engine, electrical power must be removed from the ECM for at least 15 seconds before restarting the engine.
- Crank the engine and observe the engine speed on the Cat ET status screen. If Cat ET indicates zero rpm, refer to the diagnostic functional test Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test".
Note: Upon initial cranking, the status for engine speed may indicate that the engine speed signal is abnormal. This message will be replaced with an engine speed once the ECM is able to calculate a speed from the signal.
- If an engine speed is present, check the sensor installation. If the sensor is not properly installed, the ECM may read engine speed, but the ECM cannot determine the tooth pattern. The ability for the ECM to read the tooth pattern is necessary to determine the cylinder position. Engine speed is present when engine speed is greater than 50 rpm. Refer to the diagnostic functional test Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test".
- Ensure that the valve cover connector for the injectors is fully connected and free of corrosion.
- Perform the "Injector Solenoid Test" on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoid Circuit - Test".
- 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 Operation and Maintenance Manual, "Fuel System - Prime".
- Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
- Check the fuel tank for foreign objects which may block the fuel supply.
- 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 injectors
Note: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Testing and Adjusting for more information.
- Check the fuel filters.
- 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.
- Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. Refer to Systems Operation/Testing and Adjusting, "Fuel System Pressure - Test". If the fuel pressure is low, replace the 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 the engine for combustion problems.