SHIELD GP-ENGINE COMPARTMENT 3952550 - Caterpillar

Probable Causes
Diagnostic codes
Electrical connectors
Cold mode
Injection actuation pressure
Unit injectors
Fuel supply
Air inlet and exhaust systemRecommended Actions
Note: If the symptom only occurs under certain operating conditions (high idle, full load, engine operating temperature, etc), test the engine under those conditions. Troubleshooting the symptom under other conditions can give misleading results.Diagnostic Codes
Check for active diagnostic codes on the Caterpillar Electronic Technician (ET). Troubleshoot any active diagnostic codes before continuing with this procedure.Electrical Connectors
Check the condition of the connectors at the Electronic Control Module (ECM). Check for the correct installation of the J2/P2 and J1/P1ECM connectors. Check the J300/P300 injector solenoid harness connector. Refer to Troubleshooting, "Electrical Connectors - Inspect".Cold Mode
Use Cat ET to verify that the engine has exited cold mode. Cold mode operation may cause the engine to run rough and engine power may be limited.Throttle Signal
Use Cat ET to 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 0 percent at low idle and the status should be 100 percent at high idle.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.
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 ensure that the air has been purged from the injection actuation pressure circuit.
Compare the actual actuation pressure and the desired actuation pressure on Cat ET. If these readings do not agree within 2000 kPa (290 psi), refer to Troubleshooting, "Injection Actuation Pressure - Test".Unit Injectors
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 more information.
Perform the "Cylinder Cutout Test" on Cat ET in order to identify any misfiring cylinder(s). Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for more information.Fuel Supply
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 which may block the fuel supply.
Check for air in the low pressure fuel supply circuit. If air is present in the low pressure fuel supply circuit, prime the fuel system.Air Inlet and Exhaust System
Check for an air filter restriction. Clean plugged air filters or replace plugged air filters.
Check the air inlet and exhaust system for restrictions and/or leaks.