The probable root causes are listed in order below:
Note: If the problem is intermittent and the problem cannot be duplicated, refer to Troubleshooting, "Intermittent Low Power or Power Cutout".
- Individual cylinder malfunction
- Fuel supply
- Low injection actuation pressure
- Accelerator pedal position sensor
- Power train data link
- Camshaft position sensor
- Valve lash
Perform the following diagnostic procedures in order:
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high rpm, full load, and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.
Individual Cylinder Malfunction
- Check for an individual cylinder malfunction.
- Ensure that the hydraulic electronic unit injector connector (J300/P300) is fully connected, Ensure that the connector is free of corrosion.
- Ensure that the ECM engine harness connector (J2/P2) is fully connected and ensure that the connector is free of corrosion.
- Connect Caterpillar Electronic Technician (ET) to the cab data link connector. Use the Cylinder Cutout Test. Access the Cylinder Cutout Test by selecting the "Diagnostic Menu" and the "Diagnostics Test Menu". Run the Cylinder Cutout Test in order to disable each cylinder. Disabling each cylinder allows the technician to isolate the misfiring cylinders.
If the misfiring cylinder can be isolated to a specific cylinder, refer to Troubleshooting, "Injector Solenoid Circuit - Test".
- Monitor the exhaust for smoke while the engine is being cranked.
If no smoke is present, there may be a problem with the fuel quality or there may be a problem with the fuel supply.
- Check the fuel quality.
- Check the fuel pressure. Refer to Testing and Adjusting, "Fuel System Pressure - Test".
- Ensure that the fuel system has been primed. Refer to Testing and Adjusting, "Fuel System - Prime".
- Check for fuel supply lines that are restricted.
- Check the fuel filters.
- If the temperature is below 0 °C (32 °F), check for solidified fuel (wax).
- Check for air in the fuel system. Refer to Testing and Adjusting, "Air in Fuel - Test".
Low Injection Actuation Pressure
- Check the engine oil level. Engine oil is used to activate the high pressure hydraulic pump.
- Ensure that the engine oil meets the recommendations of the engine manufacturer. Refer to Operation and Maintenance Manual for further details.
- Crank the engine and monitor the injection actuation pressure and the output of the injection actuation pressure control valve. The high-pressure oil system is operating properly if the pressure output is a minimum of 6 MPa (870 psi).
- Connect ET and check for event code 164-11 Injection Actuation Pressure system fault. If a 164-11 event code has been logged recently, refer to Troubleshooting, "Injection Actuation Pressure System-Test".
Accelerator Pedal Position Sensor
- If the engine is in the cruise control mode and the problem does not occur, check the accelerator pedal position sensor.
- Use the Cruise/Idle On/Off Switch to put the engine in Idle mode.
- Vary the engine rpm with the set/resume switches.
If both of the following conditions are met, connect ET and monitor the status of the accelerator pedal position sensor.
- The engine is stable by using idle mode to control the engine rpm.
- The engine is unstable by using the accelerator pedal position sensor.
If the status of the accelerator pedal position sensor is unstable, refer to Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - Test".
- The engine is stable by using idle mode to control the engine rpm.
- Check the "Power train Data Link". Ensure that the SAE J1939 data link is not limiting the power.
- Connect ET to the cab data link connector.
- Monitor the "Power Train Data Link" status screen while the vehicle is experiencing problems.
If the "Power Train Data Link" status screen indicates that the data link is limiting the power or the rpm, verify that the limit normal operation. If the limit is norrmal operation, refer to the vehicle OEM for repairs.
If the signal for the camshaft position sensor is lost during engine start-up, additional time may be required to start the engine. The engine may also misfire during this time until the ECM determines the proper firing order. Refer to Troubleshooting, "Engine Speed/Timing Circuit - Test".
Refer to Systems Operation, Testing and Adjusting for the correct procedure.