Unit Injector - Test-continued

TM 9-2320-312-24-2

Testing and Adjusting Section

6. Remove the suspect unit injector and check the

unit injector for signs of exposure to coolant.

Exposure to coolant will cause rust to form on

the injector. If the unit injector shows signs of

exposure to coolant, remove the injector sleeve

and inspect the injector sleeve. Replace the

injector sleeve if the injector sleeve is damaged.

Check the unit injector for an excessive brown

discoloration that extends beyond the injector

tip. If excessive discoloration is found, check

the quality of the fuel. Refer to Testing and

Adjusting, "Fuel Quality - Test". Replace the seals

on the injector and reinstall the injector. Refer

to Disassembly and Assembly Manual, "Unit

Injector - Install". Also refer to Disassembly and

Assembly Manual, "Unit Injector Sleeve - Install".

Inspect the injector for deposits of soot that are

above the surface of the seat of the injector.

Deposits of soot indicate combustion gas

leakage. The source of the leak should be found,

and the source of the leak should be remedied.

The injector will not need to be replaced if

combustion gas leakage was the problem.

7. If the problem is not resolved, replace the

suspect injector with a new injector. In order to

verify that the new injector is working properly,

perform the Cylinder Cutout Test. Use the

Caterpillar Electronic Technician (ET).