 |
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere. |
 |
Probable Causes
- Active diagnostic codes or engine events
- Incorrect engine rating
- Incorrectly programmed parameters
- Cold mode operation
- Poor electrical connections
- Incorrect status of PTO enable switch
- Incorrect status of intermediate speed switch
- Incorrect throttle signal
- Poor connections to the electronic unit injectors
- Fuel supply
- Turbocharger outlet pressure sensor (intake manifold air), rated fuel position and/or FRC fuel position
- Air inlet and exhaust system
Recommended Actions
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.
Active Diagnostic Codes or Engine Events
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (ET) and check for active codes and for logged codes. Troubleshoot any codes that are present before continuing with this procedure.
Incorrect Engine Rating
Verify that the correct engine rating is being used for the application.
Improperly Programmed Parameters
Check the following parameters on Cat ET:
- Verify that the injector codes have been programmed properly.
- "Throttle Position Sensor"
- "Desired Speed Input Configuration"
- "Direct Fuel Control Mode"
Determine the type of throttle that is used in the application. Program the parameters to match the type of throttle that is used. Refer to the diagnostic functional test Troubleshooting, "Throttle Position Sensor Circuit - Test" for more information.
Note: If the parameters are not programmed correctly, then the engine will have poor performance.
Cold Mode
Monitor the status screen on Cat ET in order to verify that the engine has exited cold mode.
Poor Electrical Connections
Check the associated wiring for damage, abrasion, corrosion or incorrect attachment on the following connectors: J1/P1 and J2/P2 ECM connectors, customer connector and throttle position sensor connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for information.
Incorrect Status of PTO Enable Switch
Connect Cat ET and verify that the "PTO enable switch" is not engaged. Remove the wiring for the PTO enable switch and cycle the power to the ECM. Verify that the problem is still present. If the problem is still present, reattach the wires and continue to next step. If the problem is resolved, refer to the diagnostic functional test Troubleshooting, "Switch Circuits - Test".
Incorrect Status of Intermediate Speed Switch
Connect Cat ET and verify that the intermediate speed switch is not engaged. Remove the wiring for intermediate speed and cycle power to the ECM. Verify that the problem is still present. If the problem is still present, reattach the wires and continue to next step. If the problem is resolved, refer to the diagnostic functional test Troubleshooting, "Switch Circuits - Test".
Incorrect Throttle Signal
Connect Cat ET to the service tool connector. View the status for the throttle position on the status screen. Operate the throttle from the low idle position to the high idle position. The status should be approximately 0 percent at low idle and the status should be approximately 100 percent at high idle. If the status cannot operate in the full range, refer to the calibration procedure Troubleshooting, "Throttle Position Sensor - Calibrate".
Diagnostic codes that are related to the J1939 data link will prevent correct operation of the throttle if the throttle position is transmitted over the data link. If there is a problem with the data link, the engine will remain at low idle until the data link is repaired.
Poor Connections to the Electronic Unit Injectors
Inspect the J2/P2 ECM connector and the J300/P300 valve cover connector for proper connections. Refer to Troubleshooting, " Electrical Connectors - Inspect". Connect Cat ET and cut out each cylinder in order to isolate the misfiring cylinder or cylinders. If the results are inconclusive, shut off half of the cylinders and repeat the cylinder cutout test on the active cylinders that are remaining in order to locate those cylinders that are missing. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoid Circuit - Test".
Fuel Supply
Check for a problem with the fuel supply and verify the fuel pressure. Verify that a fuel pressure sensor is installed on the engine. For further information, refer to Systems Operation/Testing and Adjusting, "Fuel System Pressure - Test".
Turbocharger Outlet Pressure Sensor (Intake Manifold Air), Rated Fuel Position and/or FRC Fuel Position
- With the engine at full load, monitor "Fuel Position" and "Rated Fuel Limit" on the status screen. If "Fuel Position" does not equal "Rated Fuel Limit", then check air inlet manifold pressure.
- Verify that there are no active diagnostic codes that are associated with the turbocharger outlet pressure sensor (intake manifold air) or with the atmospheric pressure sensor.
- Monitor air inlet manifold pressure and atmospheric pressure for normal operation on the status screen.
Air Inlet and Exhaust System
Check the air inlet and exhaust systems for restrictions and for leaks. Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System - Inspect". Look for an indication of the warning lamp or restriction indicators that are tripped if the filters are equipped with these devices. These indicators are associated with plugged filters. Replace the plugged air filters or clean the plugged air filters per the guidelines for operation and maintenance. Repair any leaks that are found in the system.