C3.3 Industrial Engine Caterpillar

Test the Fuel Injection Nozzles

Perform the following procedures in order to determine if a fuel injection nozzle does not work correctly.

Bench test the fuel injection nozzles at a temperature of 18° to 20 °C (64° to 70 °F).

Illustration 1	g01228000
Fuel injection nozzles and lines (1) Nut for the fuel supply line

1. Run the engine at low idle.

2. Loosen the nut for the fuel supply line (1) at the fuel injection nozzle on cylinder number 1. Do not loosen the nut more than half of a turn. Listen for the low idle to decrease or become rough. Tighten the nut for the fuel supply line on cylinder number 1. Perform this test on each cylinder.

3. The fuel injection nozzle is faulty when the nut for the fuel supply line is loosened and the following events occur:
   • The engine rpm does not decrease.

   • The engine does not idle roughly.

4. Remove the faulty fuel injection nozzle for additional testing.

   Note: If leakage occurs at the nut for the fuel supply line, make sure that fuel supply line and the nut are correctly aligned with the inlet connection of the fuel injection nozzle. Do not tighten the nut for the fuel supply line on the high pressure fuel line more than the recommended torque. If the nut is tightened more, the fuel line may become restricted or the threads of the fuel injection nozzle and the nut may be damaged.

Cleaning of the Fuel Injection Nozzles

Before a fuel injection nozzle is tested, use an ultrasonic cleaner to remove any loose carbon from the tip of the fuel injection nozzle. Do not use abrasive material or a wire brush in order to clean the nozzle.

The fuel injection nozzle is not a serviceable part. Disassembling or adjusting the nozzle will violate the standards for emissions.

Note: Extra care should be used in handling the fuel injection nozzle in order to prevent damage to the nozzle tip. A scratch or a burr could cause needle leakage or spray distortion. Dirt in the orifices of the nozzle tip can damage engine components. Dirt can also distort the spray pattern of the nozzle.

Pressure Test

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Ensure that you wear eye protection at all times during testing. When fuel injection nozzles are tested, test fluids travel through the orifices of the nozzle tip with high pressure. Under this amount of pressure, the test fluid can pierce the skin and cause serious injury to the operator. Always keep the tip of the fuel injection nozzle pointed away from the operator and into the fuel collector and extension.

Illustration 2	g01242713
5P-4150 Nozzle Testing Group (1) Fuel injection nozzle (B) 5P-4718 Adapter (C) 6V-2170 Tube assembly (D) 8T-5313 Filter (Not shown) (E) 1U-8857 Extension (F) 8S-2270 Fuel collector

1. Connect fuel injection nozzle (1) to the tooling that is shown in Illustration 2.

   Position the fuel injection nozzle so that the fuel spray is directed into Tooling (E) and Tooling (F) .

   Use Tooling (G) that is clean when the fuel injection nozzles are tested. Tooling (G) is equivalent to SAE J-967 (ISO 4113) oil.

2. Close the gauge protector valve. Close the shutoff valve. Open the pump isolator valve. In order to flush the fuel injection nozzle, operate the nozzle tester for 10 to 15 strokes at a rate of approximately 60 strokes per minute.

3. Open the gauge protector valve. Slowly increase the pressure until the valve in the fuel injection nozzle opens. Note the highest pressure indication on the dial indicator before the pointer moves to 0 kPa (0 psi). This highest pressure indication is the opening pressure of the fuel injection nozzle. The opening pressure is defined when the valve needle is lifted from the valve seat.

4. Refer to the table in Specifications, "Fuel Injection Nozzles" for the correct pressure settings.

   If the opening pressure is not within the range of the setting that is given in the table, the fuel injection nozzle must be replaced.

Test the Spray Pattern

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Ensure that you wear eye protection at all times during testing. When fuel injection nozzles are tested, test fluids travel through the orifices of the nozzle tip with high pressure. Under this amount of pressure, the test fluid can pierce the skin and cause serious injury to the operator. Always keep the tip of the fuel injection nozzle pointed away from the operator and into the fuel collector and extension.

Illustration 3	g01400474
Correct spray pattern for a fuel injection nozzle

1. Connect fuel injection nozzle (1) to the tooling that is shown in Illustration 2.

   Position the fuel injection nozzle so that the fuel spray is directed into Tooling (E) and Tooling (F) .

2. Close the gauge protector valve and the shutoff valve. Open the pump isolator valve.

3. Pump the nozzle tester at approximately 60 strokes per minute and look at the spray pattern when the fluid begins to flow through the orifices of the fuel injection nozzle.

   The spray, which flows from all of the orifices, must have the same pattern. The fuel injection nozzle is faulty if there is a difference in the vertical patterns or a difference in the horizontal patterns. Refer to the correct spray pattern in Illustration 3.

   Note: If the nozzle tester is pumped too slowly, the fuel injection nozzle can develop a hydraulic lock. If this situation occurs, release the nozzle cap nut in order to release the pressure and then tighten the nozzle cap nut to a torque of 34 ± 3 N·m (25 ± 2 lb ft). Test the spray pattern again.

   Note: Be sure that the gauge protector valve is closed before the fuel injection nozzle is removed from the nozzle tester. Closing the valve will prevent damage to the pressure gauge.

Pressure Test

Show/hide table

Ensure that you wear eye protection at all times during testing. When fuel injection nozzles are tested, test fluids travel through the orifices of the nozzle tip with high pressure. Under this amount of pressure, the test fluid can pierce the skin and cause serious injury to the operator. Always keep the tip of the fuel injection nozzle pointed away from the operator and into the fuel collector and extension.

1. Connect fuel injection nozzle (1) to the tooling that is shown in Illustration 2.

   Position the fuel injection nozzle so that the fuel spray is directed into Tooling (E) and Tooling (F) .

   Use Tooling (G) that is clean when the fuel injection nozzles are tested. Tooling (G) is equivalent to SAE J-967 (ISO 4113) oil.

2. Close the gauge protector valve. Close the shutoff valve. Open the pump isolator valve. In order to flush the fuel injection nozzle, operate the nozzle tester for 10 to 15 strokes at a rate of approximately 60 strokes per minute.

3. Open the gauge protector valve. Move the pump lever quickly downward until the valve in the fuel injection nozzle opens. Note the highest pressure indication on the dial indicator before the pointer moves to 0 kPa (0 psi). This highest pressure indication is the opening pressure of the fuel injection nozzle. The opening pressure is defined when the valve needle is lifted from the valve seat.

4. Refer to the table in Specifications, "Fuel Injection Nozzles" for the correct pressure settings.

   If the opening pressure is not within the range of the setting that is given in the table, the fuel injection nozzle must be replaced.

Fuel Injection Nozzle and Seat Test

1. Connect fuel injection nozzle (1) to the tooling that is shown in Illustration 2.

   Position the fuel injection nozzle so that the fuel spray is directed into Tooling (E) and Tooling (F) .

2. Pump the pressure of the nozzle tester at 60 strokes per minute to approximately 1030 kPa (150 psi) below the opening pressure of the fuel injection nozzle. A drop of fuel should not form on the tip of the fuel injection nozzle for at least ten seconds. A light dampness is acceptable. If the results of the tests are not acceptable, clean the fuel injection nozzle. After you clean the fuel injection nozzle and the fuel leakage still occurs, the nozzle must be replaced.