- Diagnostic codes and event codes
- Electronic Control Module (ECM)
- Engine shutdown switches
- Starting motor, solenoid, or starting circuit
- 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 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.
If the ECM is not receiving battery voltage, the ECM will not operate. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test".
If cold ambient conditions exist, check operation of starting aids. Verify that the ether system is operating correctly. Refer to Troubleshooting, "Ether Injection System - Test".
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, you must remove the electrical power to the ECM for at least 15 seconds before restarting the engine.
Starting Motor, Solenoid, or Starting Circuit
Remove the starter and visually inspect the pinion of the starter and the flywheel ring gear for damage.
Test the operation of the starting motor solenoid. Check the condition of the engine wiring for the starting motor solenoid. Test the operation of the starting motor.
If necessary, repair the starter or the starter circuit.
- 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.
- 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 Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test".
- Ensure that the J300/P300 injector valve cover entry connector 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 Troubleshooting, "Injector Solenoid Circuit - Test" for additional information.
- 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.
- 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.
- Check for air in the low pressure 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
- 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
- Purge air from the low pressure fuel supply circuit.
- Check the fuel filters.
- Cold weather adversely affects the characteristics of the fuel.
- Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. 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.