0321720 JOHNSON SCREW, Power pack case, long

Recommended Actions
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (ET) and check for active codes and/or logged codes. Wait at least 30 seconds in order for any codes to become active. Troubleshoot any codes that are present before continuing with this procedure.Note: Although a sensor's signal may be in the operational range of the sensor, certain failure modes of a sensor may produce an output signal that does not represent an accurate measurement. Use Cat ET to check that the pressures and the temperatures are fluctuating normally. Also check that the values are reasonable for the conditions that are present.Programmable Parameters
If the Electronic Control Module (ECM) has been replaced, compare the values on the engine information plate to the following parameters from Cat ET:
FRC offset
Full Load Setting (FLS)
Full Torque Setting (FTS)Determine the type of throttle that is used in the application. Program any parameters that may be associated with the throttle. Program any parameters that may be associated with this troubleshooting procedure.Note: If the parameters are not programmed correctly, then the engine will have poor performance.Cold Mode
Verify that the engine has exited cold mode. If the engine is operating in cold mode, an indicator will be displayed on the top of any of the status screens on the electronic service tool. Cold mode operation may slow throttle response.Electrical Connectors
Check the associated wiring for damage, for abrasion, for corrosion or for incorrect attachment on the following connectors: Electronic Control Module (ECM) connectors and customer connector. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".Throttle Signal
Monitor the status for "Throttle Position" on Cat ET. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed. Refer to the appropriate diagnostic functional test for your application:
Troubleshooting, "Throttle Position Sensor Circuit - Test"
Troubleshooting, "Throttle Switch Circuit - Test"
Troubleshooting, "Speed Control - Test"Unit Injectors
Use Cat ET to perform the injector solenoid test in order to determine if all of the injector solenoids are being energized by the ECM.
Perform the cylinder cutout test on Cat ET in order to check the performance of each cylinder. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoids Circuit - Test".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 the diagnostic functional test Troubleshooting, "Injection Actuation Pressure - Test".
Check the operation of the injection actuation pressure control valve. Refer to the diagnostic functional test Troubleshooting, "Injection Actuation Pressure Control Valve Circuit - Test".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 prime the fuel system. Refer to the Operation and Maintenance Manual.
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.
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.
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 injectorsNote: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Testing and Adjusting.
Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual.
Check the filtered fuel pressure while the engine is being cranked. Refer to Testing and Adjusting. 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. Refer to Testing and Adjusting.Intake Manifold (Boost) Pressure Sensor
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 intake manifold (boost) pressure.
Monitor intake manifold (boost) 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 the Operation and Maintenance Manual. 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 of the Operation and Maintenance Manual. Repair any leaks that are found in the system.