Perform the following procedures in order to determine if a fuel injection nozzle does not work correctly.
| Required Tools | ||
| Part Number | Part Name | Qty |
| 5P-4150 | Tester Group | 1 |
| 5P-7448 | Adapter | 1 |
| 6V-2170 | Tube Assembly | 1 |
| 8S-2270 | Fuel Collector | 1 |
| 1U-8857 | Extension | 1 |
| 6V-6068 | SAE J-967 Calibration Fluid | 1 |
| 8S-2245 | Injector Cleaning Tool Group | 1 |
 | |
| Illustration 1 | g00569255 |
Fuel injection nozzle assembly (1) Holder assembly (2) Shim (3) Pressure spring (4) Gasket (5) Pin (6) Gasket (7) Fuel injection nozzle (8) Retaining nut | |
- Start the engine and run the engine at low idle.
- Loosen the nut for fuel supply line at each fuel injection nozzle. Listen for the low idle to decrease at each cylinder. Also, listen for the low idle to become rough at each cylinder.
- The fuel injection nozzle may be damaged if the items that follow occur:
- Engine rpm does not decrease.
- The engine continues to run poorly.
Remove the fuel injection nozzle from the engine cylinder head for additional testing.
Note: If leakage at the nut for fuel supply line occurs, make sure that the fuel supply line and the nut for the fuel supply line 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.
- Engine rpm does not decrease.
Cleaning Of Fuel Injection Nozzles
 |
Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any product used to clean the components. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of cleaning agents. |
 |
| NOTICE |
|---|
Do not use a steel brush or wire wheel to clean the nozzle body or the nozzle tip. Use of these tools can cause a small reduction of orifice size, and this will cause a large reduction in engine horsepower. Too much use of a wire brush will also remove the coating that is on the fuel injection nozzle for protection. |
 | |
| Illustration 2 | g00570038 |
Remove carbon with the 8S-2258 Brass Wire Brush which is included in the 8S-2245 Injector Cleaning Tool Group . | |
Before the fuel injection nozzle can be tested, remove all loose carbon around the tip of the fuel injection nozzle. Use the 8S-2245 Injector Cleaning Tool Group to clean the fuel injection nozzle. Refer to Special Instruction, SEHS8627, "Use of 8S-2245 injection Nozzle Cleaning Tool Group " for more information.
- Remove retaining nut (8) from the holder assembly (1). Remove the tip assembly of fuel injection nozzle (7). Wash the needle valve and the body.
Note: Do not mix the needle valve and bodies of different nozzles. The components of the nozzle tip assembly are a precise fit. The components must not be exchanged with other components. Do not touch the sliding surfaces of the needle valve.
- Wash tip assembly of fuel injection nozzle (7) in clean kerosene. After washing, assemble the needle valve and the body in clean fuel.
- Tighten retaining nut (8) to a torque of 34 ± 5 N·m (25 ± 4 lb ft).
- Replace the nozzle tip if the discharge pattern is still unacceptable.
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 that is in the orifices of the nozzle tip can damage engine components. Dirt can also cause spray distortion.
Fuel Injection Lines
Fuel from the fuel injection pump goes to the fuel injection nozzle through the fuel injection lines. When the fuel injection lines are disconnected or removed, always put caps or plugs on the ends of the lines in order to keep dirt out of the lines. Ensure that all of the line clamps and all of the vibration dampers are installed in the original locations when the fuel injection lines are installed.
Note: Fuel injection lines can leak if the fuel injection lines are bent or damaged. Fuel injection lines can also leak if the fuel injection lines are rubbing. Leakage of fuel can also cause a fire. Replace any lines which have damage or leaks that can not be corrected when the nuts are tightened to the correct torque.
Note: Ensure that the fuel injection line clamps are installed in the correct location. Incorrectly installed clamps may allow the fuel injection lines to vibrate. Incorrectly installed clamps may allow the fuel injection lines to become damaged. The damaged lines may leak. Leakage of fuel can cause a fire.
All nuts that hold a fuel injection line to the fuel injection nozzle or to the fuel injection pump must be tightened to the correct torque. If the nut is loose, fuel will leak from the connection. If the nut is too tight, the inside diameter of the fuel line will become smaller. This causes a restriction to the flow of fuel in the fuel line. Use a torque wrench to tighten the nuts of the fuel injection lines to a torque of25 N·m ( 18 lb ft).
Pressure Test
|
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. |
|
| NOTICE |
|---|
Do not use dirty test fluids when you test fuel injection nozzles. Also, do not test fuel injection nozzles unless you have the correct service tools.The use of dirty test fluids and the use of incorrect service tools will result in damage to fuel injection nozzles. |
 | |
| Illustration 3 | g00820427 |
Test the pressure for the fuel injection nozzle by using 5P-4150 Nozzle Testing Group . (9) 5P-7448 Adapter (10) Fuel injection nozzle (11) 5P-4721 Tube (12) 1U-8857 Extension (13) 8S-2270 Fuel Collector (14) 8T-5313 Filter | |
Note: This procedure is a test of the first opening pressure of the fuel injection nozzle. Testing for the second opening pressure of the fuel injection nozzle is not performed by this procedure. A test of the second opening pressure requires the disassembly of the fuel injection nozzle and the use of special shims. Disassembly of the fuel injection nozzles may invalidate the standards for emissions of the engine.
- Connect fuel injection nozzle (10) to the tooling that is shown in Illustration 3.
The spray from the fuel injection nozzle must be directed into 1U-8857 Extension (12) and 8S-2270 Fuel Collector (13) .
Refer to the table in the Specifications, "Fuel Injection Nozzles" topic for the correct pressure settings. If the opening pressure is not within the range of the setting which is given in the table, the fuel injection nozzle must be replaced.
Use clean 6V-6068 Calibration Fluid when the fuel injection nozzles are tested. The calibration fluid is similar to SAE J-967 (ISO 4113) oil.
- Close the gauge protector valve. Close the shutoff valve. Open the pump isolator valve. Flush the fuel injection nozzle by operating the nozzle tester. Operate the nozzle tester for 10 to 15 strokes at a rate of approximately sixty strokes per minute.
- 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 will happen when valve needle rises from the nozzle seat. Refer to Specification, "Fuel Injection Nozzles" for the correct pressure setting.
Back Leakage Test
- Connect fuel injection nozzle (10) to the tooling that is shown in Illustration 3.
Position the fuel injection nozzle so that the direction of the fuel spray is into 1U-8857 Extension (12) and 8S-2270 Fuel Collector (13) .
- Pump the pressure to about 1957 kPa (284 psi) below the opening pressure of the fuel injection nozzle. Refer to the Specifications, "Fuel Injection Nozzles" topic for the correct setting of the opening pressure. Release the handle. When the pressure begins to decrease, note the time that is required for the pressure to decrease to approximately 0 kPa (0 psi). If the fuel injection nozzle is not damaged, the time will not be less than 5 seconds or more than 45 seconds.
If the time that is required for the pressure to decrease to 0 kPa (0 psi) is less than 5 seconds, too much fuel is leaking around the valve needle. Replace the fuel injection nozzle.
- Look for any leakage from the pressure faces of the holder and the retaining nut of the fuel injection nozzle. If leakage is visible, make sure that the components are tightened to the correct torque.
If leakage continues to occur, unscrew the retaining nut from the body. Inspect the threaded surfaces for foreign particles and damage. If the faces are clean and undamaged, test the fuel injection nozzle. Repeat Steps 1 and 2.
 | |
| Illustration 4 | g00570047 |
Leakage test after ten seconds (A) Acceptable (B) Unacceptable | |
Fuel Injector Nozzle And Seat Test
- Connect fuel injection nozzle (10) to the tooling that is shown in Illustration 3.
Position fuel injection nozzle so that the direction of the fuel spray is into 1U-8857 Extension (12) and 8S-2270 Fuel Collector (13) .
- Pump the pressure of the nozzle tester to approximately 1957 kPa (284 psi) below the opening pressure of the fuel injection nozzle. Fuel should not collect on the tip of the fuel injection nozzle in a sufficient quantity in order to drip from the tip for at least ten seconds. A light dampness is acceptable.
If the results of the tests are not acceptable, replace the fuel injection nozzle.
Test The Spray Pattern
|
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. |
|
The pressure adjustment must be correct before the spray pattern is tested.
 | |
| Illustration 5 | g00322083 |
Correct Spray Pattern For Fuel Injector Nozzles
- Connect fuel injection nozzle (10) to tooling that is shown in Illustration 3.
Position fuel injection nozzle so that the direction of fuel spray is into 1U-8857 Extension (12) and 8S-2270 Fuel Collector (13) .
- Close the gauge protector valve and the shutoff valve. Open the pump isolator valve.
- Quickly pump the nozzle tester 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. A difference in the nozzle spray patterns indicates that fuel injection nozzle is damaged. Refer to the correct spray pattern in Illustration 5.
Note: Be sure that the gauge protector valve is closed before fuel injection nozzle is removed from the nozzle tester. Closing the gauge protector valve will prevent damage to the pressure gauge.