Probable Causes
- Diagnostic codes, event codes, and the power supply for the Electronic Control Module (ECM)
- Air inlet heater
- Engine shutdown switches
- Engine speed/timing
- Injection actuation pressure
- Unit injectors
- Fuel supply
- Combustion
Recommended Actions
Diagnostic Codes, Event Codes, and ECM Power Supply
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.
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 Circuit - Test".
Air Inlet Heater
Ensure that the air inlet heater is working properly. Ensure that the heater element is in good repair. For additional information on the air inlet heater, refer to Troubleshooting, "Air Inlet Heater Circuit - Test".
Engine Shutdown Switches
The engine shutdown switches should be in the RUN position. Use Cat ET to verify the status of the shutdown switches. When a shutdown occurs, the shutdown switch must be reset prior to restarting the engine. On some applications, the electrical power must be cycled before the ECM will allow engine cranking. Remove electrical power from the ECM for at least 15 seconds prior to restarting the engine.
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 Circuit - Test".
Engine Speed/Timing
- 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 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.
- 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.
Injection Actuation Pressure
- Check the engine oil level. Engine oil supplies the injection actuation pressure circuit. The engine oil must be kept at the proper level for fuel injection.
- If service has recently been performed on the engine, air may be present in the injection actuation pressure circuit. Allow the engine to fully warm up and operate the engine under load in order to purge the air from the injection actuation pressure circuit.
- Check the injection actuation pressure. Refer to Troubleshooting, "Injection Actuation Pressure - Test" for the correct procedure.
- Check the operation of the injection actuation pressure control valve. Refer to Troubleshooting, "Injection Actuation Pressure Control Valve Circuit - Test" for the proper troubleshooting procedure.
Unit Injectors
Perform the "Injector Solenoid Test" on Cat ET in order to determine if each of the injector solenoids are being energized by the ECM. Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for additional information.
Fuel Supply
- Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. If necessary, add fuel to the fuel tank. If the engine has been run out of fuel, it will be necessary to purge the air from the fuel system.
- 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 debris or 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.
- Replacement of the fuel filters
| NOTICE |
|---|
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again. |
- Check fuel quality. Cold weather adversely affects the characteristics of the fuel.
- Check the filtered fuel pressure while the engine is being cranked. 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.
Combustion
Check for combustion problems.