2006/11/13 Caterpillar

Machine Engine:

3408E (S/N: 99C1-UP; 5XD1-UP)

3412E (S/N: 80M1-UP; 5JJ1-UP)

Perform the following troubleshooting procedure if the 235-2026 Unit Injector Hydraulic Pump Gp or 10R-1001 Unit Injector Hydraulic Pump Gp is not providing the required injection actuation pressure during engine cranking.

Troubleshooting

1. Check the engine oil level. if necessary, add oil. Verify that the pressure for the lube oil system is accurate.

   Note: Engine oil supplies the injection actuation pressure circuit. proper engine oil level is necessary for fuel injection.

2. Crank the engine while observing the injection actuation pressure on the Caterpillar Electronic Technician (ET) status screen. if the injection actuation pressure is at least 5000 ± 200 kPa (725 ± 29 psi), the problem is not in the injection actuation pressure control system.

3. Check the seals on the injection actuation pressure control valve. if the seals are faulty, replace the seals and repeat Step 1.

4. Check the wiring harness to the injection actuation pressure control valve for opens and/or shorts.

5. Measure the coil resistance on the injection actuation pressure control valve. If the coil resistance is not between 5.0 Ohms and 15.0 Ohms, replace the injection actuation pressure control valve.

6. If the injection actuation pressure during cranking is less than 5000 ± 200 kPa (725 ± 29 psi), the high pressure oil supply circuit may have a leak.

   1. Unplug the injection actuation pressure control valve and the unit injector connectors.

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   This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

   2. Disable the unit injectors with Cat ET and/or the engine shutdown switch.

   3. Remove the valve mechanism cover.

   4. Crank the engine while checking the drain holes in the unit injector adapter and the jumper block seals for leaks.

   5. Excessive leakage will result in a large stream of oil flow from the affected unit injector adapter drain hole(s), with easily visible splashing of engine oil off of the bottom of the jumper block adapter oil shield(s). In the event an excessively leaking unit injector(s) is diagnosed, change only the excessively leaking unit injector(s). Leaking jumper block seals can also create this problem, and can be diagnosed using the technique described above. Replace leaking seals.

   6. If the problem persists, there may be a pump compensator displacement control problem. Correct by replacing the 166-5985 Compensator Kit. Adjust the load sensing spool spring load by turning the retaining screw so that 5000 ± 200 kPa (725 ± 29 psi) is produced while cranking the engine with the injection actuation pressure control valve unplugged.

   7. If the injection actuation pressure remains low after installing a new 166-5985 Compensator Kit, install a longer compensator plug. The longer compensator plug that is marked with a "D" is part of 161-8627 Plug Kit. If the injection actuation pressure is above the specified range, select the shorter compensator plug from the plug kit that is marked with a "B".

   8. If the pressure cannot be obtained, rebuild the pump with a 225-8545 Pump Kit or replace the old pump with a 10R-1001 Unit Injector Hydraulic Pump Gp .

Critical Requirements for Installation of 10R-1001 Unit Injector Hydraulic Pump Gp

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To avoid personal injury, do not bend the fuel outlet lines.

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Personal injury or death can result from high voltage. Moisture could create paths of electrical conductivity. Make sure the unit is off line (disconnected from utility and/or other generators), locked out and tagged "Do Not Operate".

• Steam clean the engine before removing the old pump.

• Drain all of the oil from the supply line to the pump.

• Keep all open oil lines covered.

• Clean the filter bypass valves and inspect filter bypass valves.

• Change the engine oil and oil filters before installation of the new pump.

• Prime the new pump with clean unused engine oil prior to starting the engine.

Refer to Disassembly and Assembly for additional information.