- Diagnostic codes
- Event codes
- Fuel supply
- Electrical power supply to the Electronic Control Module (ECM)
- Electrical connectors
- Air inlet and exhaust system
- Engine shutdown switches (if applicable)
- Engine speed/timing
- Unit injectors
- Combustion
Diagnostic Codes, Event Codes, and Electrical Power Supply to the ECM
Certain diagnostic codes and/or event codes may prevent the engine from starting. Connect 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.
Note: If Cat ET will not communicate with the ECM, the problem is most likely with the electrical power supply to the ECM. Refer to Troubleshooting, "Electrical Power Supply - 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 prime the fuel system. Refer to Operation and Maintenance Manual for the correct procedure.
- 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 supply system if any of the following procedures have been performed:
- Replacement of the fuel filters
- Service on the low pressure fuel supply circuit
Note: A sight glass in the supply line is helpful in diagnosing air in the fuel. Refer to the Systems Operation/Testing and Adjusting manual for more information.
- Replacement of 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.
Electrical Power Supply to the Electronic Control Module (ECM)
Check power to the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test".
Note: If the ECM is not receiving battery voltage, the ECM will not communicate.
Inspect each connector for moisture and corrosion. Also, inspect the harness from the ECM to the sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect".
- Check the air filter restriction indicator for a plugged filter. If necessary, service the engine. Refer to the Operation and Maintenance Manual.
- Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/Testing and Adjusting.
- Check flame arrester for blockage on ATEX engines.
Engine Shutdown Switches (if applicable)
The engine shutdown switches should be in the OFF position. Use Cat ET to verify the status of the shutdown switches. When a shutdown occurs, the keyswitch must be turned to the OFF position for at least 15 seconds before restarting the engine.
The air shutoff switch must be in the OPEN position on an ATEX engine.
- Crank the engine and observe the engine speed on the Cat ET status screen. If Cat ET indicates zero rpm, refer to Troubleshooting, "Engine Speed/Timing Sensor".
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.
- Ensure that the timing reference gear is installed correctly. The engine will not start if the gear was installed backward. Check for proper orientation between the crankshaft and camshaft drive gears. Correct the orientation and/or replace the drive gear, if necessary. Refer to the Disassembly and Assembly manual.
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 Troubleshooting, "Injector Solenoids" for additional information.
Check for mechanical problems in the combustion system.