350-05124-0 Tohatsu RATCHET GUIDE "B"

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Electronic Unit Injector
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Schematic for electronic unit injector
Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.
Thoroughly inspect the ECM engine harness connector J2/P2 and the solenoid connector for the Injector J300/P300. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the J2/P2 ECM connector and the J300/P300 valve cover connector that are associated with injector solenoids.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the J300/P300 valve cover connector in order to ensure the proper mating of the connector.
Check the harness and wiring for abrasion and pinch points from the injectors to the ECM.Expected Result:All connectors, pins, and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion, or pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Perform the following repair:Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. CHECK FOR LOGGED DIAGNOSTIC CODES REGARDING INJECTOR SOLENOIDS
Connect the Caterpillar Electronic Technician (ET) to the data link connector.
Turn the key switch to the ON position.
Monitor the logged diagnostic code screen on Cat ET.Expected Result:One or more diagnostic codes for the injectors have been logged:Results:
OK - Proceed to Test Step 4.
Not OK - Proceed to Test Step 3.Test Step 3. CHECK THE VARIATION OF THE INJECTORS FROM A CYLINDER TO A CYLINDER
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"Automated Cylinder Cutout Test" screen in Caterpillar Electronic Technician (Cat ET)
Connect Cat ET to the data link connector.
When possible, put the truck on a dynamometer.
Start the engine.
Allow the engine to warm up to normal operating temperature 77 °C (171 °F).
After the engine is warmed to operating temperature, access the "Cylinder Cutout Test" by accessing the following display screens in order:
"Diagnostics"
"Diagnostic Tests"
"Cylinder Cutout Test"
Enable the cooling fan, if the fan is not controlled by the ECM. If the ECM controls the cooling fan, the cooling fan will start automatically when the test begins.
Shut off all parasitic loads such as the air conditioning and the air compressors which could affect the results of the test.
Set the engine speed to 1000 20 rpm.
Select the start button at the bottom of the screen for the "Cylinder Cutout Test".
Select the "4 Cylinder Cutout Test" which is the default test.
Follow the instructions that are provided in the Cylinder Cutout Test. The Cylinder Cutout Test is interactive so the procedure is guided to the finish.Note: The "Manual Cylinder Cutout Test" is also available. Access the manual test by selecting the "Change" button on the Cat ET screen for the Cylinder Cutout Test. The "4 Cylinder Cutout Test" is the recommended starting procedure. The automated tests run twice collecting data. The two sets of data are analyzed and an "OK" or "NOT OK" result is displayed.Expected Result:All cylinders indicate "OK" on Cat ET.Results:
OK - Repair: If the engine is misfiring or if the engine has low power, refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" and Troubleshooting, "Low Power/Poor or No Response to Throttle".If a diagnostic code results from running the Cylinder Cutout Test, proceed to Test Step 4.
Not OK - Proceed to Test Step 4.Test Step 4. USE THE INJECTOR SOLENOID TEST TO TEST THE INJECTOR SOLENOIDS
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"Injector Solenoid Test" screen in Caterpillar Electronic Technician (Cat ET)
Start the engine.
Allow the engine to warm up to 77 °C (171 °F) which is the normal operating temperature.
Turn the key switch to the OFF position.
Connect Cat ET to the data link connector.
Turn the key switch to the ON position.
After the engine is warmed to operating temperature, access the "Injector Solenoid Test" by accessing the following display screens in order:
"Diagnostics"
"Diagnostic Tests"
"Injector Solenoid Test"
Activate the test.Note: Do not confuse the Injector Solenoid Test with the Cylinder Cutout Test. The Cylinder Cutout Test is used to shut off fuel to a specific cylinder while the engine is running. The Injector Solenoid Test is used in order to actuate the injector solenoids. This allows the click of the injector solenoids to be heard when the engine is not running in order to determine that the circuit is functioning properly.
As each solenoid is energized by the ECM an audible click can be heard at the valve cover. Listen for a click at each valve cover. A black square will appear over the cylinder number when the cylinder is being fired.
Perform the Injector Solenoid Test at least two t