TANK GP-FUEL 7Y8739 - Caterpillar

Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Remove the valve cover.
Disconnect the harness from the problem injector. Disconnect the harness from the other injector that has the wiring for the solenoid common.
Thoroughly clean the terminals of both injectors and the harness.
Exchange the harness between the two injectors that share the solenoid common .
Turn the keyswitch to the ON position.
Perform the injector solenoid test at least two times.Expected Result:Exchanging the harness between the two injectors caused the problem to move to the other injector on Cat ET.Results:
OK - The problem moved to the other injector.Repair: Perform the following repair:Replace the faulty injector. Restore the wiring to the proper injectors.Verify that the repair eliminates the problem.STOP
Not OK - The problem did not move to the other injector.Repair: Perform the following repair:Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.STOPTest Step 11. Check the Engine Harness Under the Valve Cover for an Open Circuit in the Wiring for the Solenoid Common
Illustration 5 g00663574
Harness terminals of Electronic Unit Injector
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Remove the valve cover.
Disconnect each of the injectors that indicate an "OPEN" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.
Attach a jumper wire to both terminals of the injector harness for the two injectors that share the wiring for the solenoid common.
Turn the keyswitch to the ON position.
Perform the injector solenoid test at least two times.Expected Result:The cylinders with the short in place indicate an "OPEN".Results:
OK - Repair: Perform the following repair:
Replace the engine harness under the valve cover.
Use the injector solenoid test to check the installation of the new harness before installing the valve covers.
Verify that the repair eliminates the problem.STOP
Not OK - Both injectors indicate "SHORT".Repair: Perform the following repair:Both injectors indicate "SHORT". Replace Both injectors.Verify that the repair eliminates the problem.STOPTest Step 12. Check the Engine Harness Under the Valve Cover for Short Circuits in the Injector Wiring
Electrical shock hazard. The electronic unit injector system uses 90-120 volts.
Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned off.
Remove the valve cover.
Disconnect each of the injectors that indicate a "SHORT" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.
Turn the keyswitch to the ON position.
Perform the injector solenoid test at least two times.Expected Result:Both cylinders indicate an "OPEN".Results:
OK - Leave the injector wires disconnected. Neither of the injector wires are shorted to the engine. Proceed to Test Step 13.
Not OK - Repair: Perform the following repair:Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.STOPTest Step 13. Check for a