345-01150-1 Tohatsu CHECK VALVE ASSEMBLY

Recommended Actions
Diagnostic Codes, Event Codes, and ECM Power Supply
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.Note: If Cat ET will not communicate with the ECM, the problem is most likely with the electrical power supply to the ECM. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test".Starting Circuit
Test the operation of the starting motor and associated circuit components. Refer to the Systems Operation/Testing and Adjusting manual.Flash File
Verify that the correct flash file has been flashed into the ECM. Refer to programming parameters Troubleshooting, "Flash Programming".Starting Aids
Air Inlet Heater (if applicable)
Make sure that the air inlet heater is programmed to the On position. For additional information on the air inlet heater, refer to the diagnostic functional test Troubleshooting, "Air Inlet Heater Circuit - Test".Engine Shutdown Switches (If Applicable)
The engine shutdown switches should be in the OFF position. Use Cat ET to verify the status of the shutdown switches. When a shutdown occurs, the engine control must be in the OFF/RESET mode for at least 15 seconds before restarting the engine.Air Shutoff System (If Applicable)
Check the air shutoff mechanism. If an engine overspeed has occurred, the keyswitch must be cycled. There may be a manual reset for the air shutoff mechanism that is on 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.
Ensure that the timing reference gear is installed correctly. The engine will not start if the gear was installed backward. Check for proper orientation between the crankshaft and camshaft drive gears. Correct the orientation and/or replace the drive gear, if necessary. Refer to Disassembly and Assembly.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 the diagnostic functional test Troubleshooting, "Injector Solenoid Circuit - Test".Verify that the injection system is delivering the correct pressure. Refer to the diagnostic functional test Troubleshooting, "Injection Actuation Pressure - 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 prime the fuel system. Refer to 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 foreign objects which may block the fuel supply.
Check for air in the low pressure fuel supply 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.
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 low pressure fuel supply circuit. Refer to Operation and Maintenance Manual, "Fuel System - Prime".
Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the applicable Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
Check the fuel pressure after the fuel filter 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.Combustion
Check for combustion problems.