INSULATOR 7B4226 - Caterpillar

Probable Causes
Diagnostic codes and event codes
Electronic Control Module (ECM)
Starting aids (if applicable)
Engine shutdown switches
Engine speed/timing
Unit injector
Fuel supply
CombustionRecommended Actions
Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may prevent the engine from starting. Connect the 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.Electronic Control Module (ECM)
If the ECM is not receiving battery voltage, the ECM will not operate. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test".Starting Aids (If Applicable)
If cold ambient conditions exist, check operation of starting aids. Refer to the appropriate diagnostic functional test for troubleshooting information.Engine Shutdown Switches
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, electrical power must be removed from the ECM for at least 15 seconds before restarting the engine.Engine Speed/Timing
Crank the engine and observe the engine speed on the Cat ET status screen. If Cat ET indicates zero rpm, refer to the diagnostic functional test 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 the diagnostic functional test Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test".Unit Injector
Ensure that the valve cover connector for the injectors 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 the diagnostic functional test Troubleshooting, "Injector Solenoid Circuit - Test".Fuel Supply
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. Refer to Operation and Maintenance Manual, "Fuel System - Prime".
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.
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 for more