Procedimiento de como medir la fuga en inyectores del motor C6 y C4
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Bienvenido: r050sxmo
Producto: WHEEL LOADER
Modelo: 938H WHEEL LOADER JKM
Configuración: 938H Wheel Loader JKM00001-UP (MACHINE) POWERED BY C6.6 Engine
Instrucción EspecialHigh Leakoff of the Electronic Unit Injector on C6.6 and C4.4 Engines{1251, 1290}
Número de medio-KENR6938-07 Fecha de publicación -04/10/2012 Fecha de actualización -04/10/2012
i05117850
High Leakoff of the Electronic Unit Injector on C6.6 and C4.4 Engines
There have been isolated occurrences of excessive fuel leakage past the electronic unit injectors on some engines.
Accelerated wear on the delivery valve results in an increased leak rate.
For six cylinder engines, the fuel injection pump cannot generate enough fuel flow or volume in order to compensate for the leakoff rates above a critical value of 38 mL (1.3 oz) per 30 seconds of cranking at a speed of 150 rpm.
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For four cylinder engines, the critical value is 25 mL (0.85 oz) per 30 seconds of cranking at a speed of 150 rpm.
If the engine turns over but the engine does not start, refer to Troubleshooting, "Engine Cranks but Will Not Start". Perform the following procedure when directed by Troubleshooting, "Engine Cranks but Will Not Start". The procedure will help to assess the amount of fuel pressure leakoff within the high-pressure fuel system.
Note: The engine may start, but you may still have high leakoff within the high-pressure fuel system.
NOTICE
Do not perform any procedure in this Special Instruction until you read this information and you understand this information.
Note: If the electronic unit injectors are replaced, ensure that the valve bridge is seated in the correct position.
Failure to carry out this procedure correctly may result in engine failure. For further information, refer to Engine News, SEBD9574, "Improved Valve Bridges" and Service Magazine, SEPD0975, "Improved Valve Bridges".
Note: If applicable, a completed service report (form number 089479-00) must be included with the returned parts. ECM warranty report downloads, datalogs, and any special test results as directed by repair procedures are to be uploaded to SIMS. Checklists that are packaged with replacement parts are to be completed and packaged with parts being returned.
Refer to Special Instruction, REHS7790, "Improved Fuel System Diagnostic Test Documentation for Certain C4.4 and C6.6 Engines" for additional diagnostic test documentation.
Test Procedure for Measuring High Leakoff for the Electronic Unit Injectors
NOTICE
Before beginning any work on the fuel system, refer to Operation and
Maintenance Manual, "General Hazard Information and High
Pressure Fuel Lines" for safety information.
Refer to Systems Operation, Testing and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of
cleanliness that must be observed during ALL work on the fuel system.
NOTICE
After 30 seconds of cranking the engine, release the starter switch or button and wait 2 minutes to allow the starting motor to cool before
attempting to start the engine again.
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Note: Caterpillar recommends that the procedure should be carried out without starting the engine.
Required Tools
Tool Part Number Part Description Qty
A 300-4988 Fuel Leakoff Kit 1
Table 1
Ensure that the engine is shut down. Remove the banjo bolt that is located on the bottom of the fuel transfer pump. Retain the sealing washers for use in step 10.b.
1.
Illustration 1 g01402111
Typical example
Install Tooling (A) to the fuel transfer pump.2.
Note: Tooling (A) will replace the banjo bolt that was removed in step 1. Do not substitute Tooling (A).Tooling (A) is specially designed for the test.
Install a clear plastic hose (1). Place the opposite end of the plastic hose into a suitable container that is clean.3.
Connect the electronic service tool to the diagnostic connector.4.
Disconnect the three harness connectors for the electronic unit injectors at the valve mechanism cover base to prevent starting the engine.
5.
Perform a data log of the following parameters at a sample rate of 240 samples per minute.6.
ECM Parameters
Active Diagnostic Codes that are present◦
Atmospheric Pressure◦
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Start the data log. Crank the engine for 30 seconds.7.
End the data log.8.
Record the amount of fuel that has been collected in the container from the leakoff connector on the cylinder
head. Conduct the test three times. Calculate the average of the three values.
9.
Refer to step 10.a or step 10.b for the relevant values for your engine.10.
For six cylinder engines, if more than 38 mL (1.3 oz) of fuel has been collected during the 30 second crank test, then there is high leakoff of the electronic unit injectors.
a.
For six cylinder engines, if less than 38 mL (1.3 oz) of fuel has been collected for the 30 second crank
test, then there is not high leakoff of the electronic unit injectors.
Refer to Troubleshooting, "Engine Cranks but Will Not Start" in order to diagnose the problem.
For four cylinder engines, if more than 25 mL (0.85 oz) of fuel has been collected during the 30 second crank test, then there is high leakoff of the electronic unit injectors.
b.
For four cylinder engines, if less than 25 mL (0.85 oz) of fuel has been collected for the 30 second cranktest, then there is not high leakoff of the electronic unit injectors.
Refer to Troubleshooting, "Engine Cranks but Will Not Start" in order to diagnose the problem.
Remove Tooling (A). Install the banjo bolt and two new washers to the fuel transfer pump.11.
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End of the test. If there is high leakage of the high-pressure fuel system, proceed to ""Measuring the Fuel Injection Pump Flow and High Leakoff for the Individual Electronic Unit Injector" ".
12.
Measuring the Fuel Injection Pump Flow and High Leakoff for the Individual Electronic Unit Injector
This procedure provides a method to evaluate the internal leakage condition of the following components:
Fuel injection pump•
Fuel pressure relief valve•
Electronic unit injectors•
The procedure provides a method to compare internal fuel leakage to a precision calibrated orifice.
Use the ""Test Kit Data Sheet" " for recording the test data. For an example of the test process calculations refer to ""Example Calculations Sheet" ".
Use the checklist form provided with the replacement component to document the test results.
Do not discard this form. A completed checklist is required to be included in the claim story. A completed checklist
is to be included with any fuel injection system component returned for credit.
Use the following procedure to aid in the diagnosing of the following conditions:
The engine cranks but the engine does not start•
The fuel rail pressure is low•
There has been a low rail-pressure event•
The engine fuel injection system has excessive internal fuel pressure leakage•
Verify the following before continuing with this procedure:
No fuel injection pump or electronic unit injector diagnostic trouble codes are active•
No external high-pressure leaks exist•
The cranking speed of the engine is at least 150 rpm•
Note: A battery booster is essential to maintain consistent cranking speed of at least 150 rpm for all fuel injectionpump and electronic unit injector tests.
The low-pressure fuel system is providing a minimum of 50 kPa (7 psi) of pressure to the fuel injection pump.•
Determine if the pressure in the fuel manifold (rail) during engine cranking is less than 22 MPa (3200 psi). This will
assist when conducting the procedure in Troubleshooting, "Engine Cranks but Will Not Start".
If troubleshooting for low rail-pressure event, first warm up the engine to improve the test results.
If possible run at high speed and load to duplicate the low rail-pressure event conditions•
If it is not possible to put load on engine, run the "Fuel System Verification Test". This will increase the desired rail-pressure to help get the fuel injection pump and electronic unit injectors warm.
•
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Electrical Shock Hazard. The electronic unit injectors use DC voltage.
The ECM sends this voltage to the electronic unit injectors. Do not come
in contact with the harness connector for the electronic unit injectors while the engine is operating. Failure to follow this instruction could
result in personal injury or death.
NOTICE
Ensure that all adjustments and repairs that are carried out to the fuel
system are performed by authorized personnel that have the correct
training.
Before beginning ANY work on the fuel system, refer to Operation and Maintenance Manual, "General Hazard Information and High
Pressure Fuel Lines" for safety information.
Refer to System Operation, Testing and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of
cleanliness that must be observed during ALL work on the fuel system.
Note: The pressures generated during this test are lower than those generated during normal operation. During this test, the fuel injection lines may be removed and reused when performing this procedure due to the lower pressuresthat are generated during the testing. This is the only condition where reuse of a fuel injection line is allowed.
Note: All connections must be clean prior to assembly. Carefully inspect all connections, caps, and lines before each use. When not in use, caps, plugs, and orifice from the kit must be capped to prevent damage and debris entry.
Use the gauge pin and an aerosol cleaner to ensure that the orifice is clean before performing this procedure.
Measure the Pressure of the Fuel Injection Pump
This part of the process will set up the test components and determine if the fuel injection pump or the fuel pressure
relief valve is defective for internal leakage.
Obtain the Test Kit Data Sheet. Use the Test Kit Data Sheet to record all test measurements.1.
Remove the fuel injection lines. Refer to Disassembly and Assembly, "Fuel Injection Lines - Remove" for the correct procedure.
2.
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Connect one of the fuel injection lines (1) to the fuel manifold (rail) at cylinder number 1 fuel outlet connection. Connect the discharge orifice assembly (2) to the other end of the fuel injection line. Install the rail plug assemblies onto the fuel manifold (rail) for all remaining cylinder fuel outlet connections.
3.
Note: The collecting cylinder must be mounted at a position lower than the fuel manifold (rail) on the engine.
Insert the drain hose (3) from the outlet of the discharge orifice assembly into the collecting cylinder. Refer to illustration 3.
4.
Disable all electronic unit injectors by disconnecting the injector harness connectors. Leave the electronic unitinjectors disabled for the duration of the test.
5.
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(2) Pump test engine speed measured when peak pressure occurs
(3) 2 to 5 second typical for pressure to build
(4) More than 5 seconds with pressure build required to capture peak
Determine the fuel pressure in the fuel manifold (rail) and the engine speed where the peak pressure was selected. Typically, pressure will start building after 2 to 5 sec and then there should be samples taken for 5
more seconds. Illustration 5 shows an example of selecting the peak pressure and corresponding speed.
8.
Use the engine speed where the fuel pressure in the fuel manifold (rail) was selected from step 8 to determine the Minimum Cranking Pressure (MCP). Refer to table 4 for engine size and cranking rpm.
If the fuel pressure in the fuel manifold (rail) is less than the Minimum Cranking Pressure (MCP), inspect the Pressure Relief Valve (PRV) for leakage and retest. The PRV can be checked for leakage by inspecting the
outlet of the valve for any fuel leakage. Refer to Special Instruction, REHS5712, "Inspecting the Fuel Rail High Pressure Relief Valve" for the correct procedure.
10.
If the Pressure Relief Valve (PRV) does not leak, and fuel pressure in the fuel manifold (rail) displayed in the electronic service tool graph is less than the Minimum Cranking Pressure (MCP), remove, clean, and inspect the outlet check valves and retest. Refer to Special Instruction, REHS3751, "Servicing the Outlet Check Plugs
on the Fuel Injection Pump" for the correct procedure.
11.
Determine the new MCP based on the retest speed. If the fuel pressure in the fuel manifold (rail) displayed in the electronic service tool graph is still less than MCP, replace the fuel injection pump. Refer to Disassembly and Assembly for the correct procedures.
12.
If the fuel pressure in the fuel manifold (rail) is greater than MCP, record the fuel pressure in the fuel manifold
(rail) and peak pump rail pressure engine speed, which will be used for injector testing. proceed to ""Measure Electronic Unit Injector Number 2 Leakage" ".
13.
Measure Electronic Unit Injector Number 2 Leakage
This part of the procedure will determine if individual electronic unit injectors are defective for internal leakage.
Note: It is possible to measure the individual electronic unit injectors for leakage in any order. Use the order that is easiest for the engine in a particular application.
Note: If the test speed for the electronic unit injector number 2 changes by more than 25 rpm from the measurement of Pump Test speed or drops below 150 rpm, the use of a battery booster is essential to maintain uniform speed with the pump test. This will improve the accuracy of test results. Make sure that there are no leaks during the test as the
measurement will be invalid.
Note: When 3 or more electronic unit injectors are found to have excessive leakage, stop the test. Record the results of the leak rate for each electronic unit injector tested. Then replace all electronic unit injectors. Refer to Disassembly and Assembly for the correct procedure.
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Install existing fuel injection line for number 2 cylinder. Refer to Disassembly and Assembly, "Fuel Injection Lines - Install" for the correct procedure. Refer to illustration 6.
1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" whilecranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
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(2) Injector test engine speed measured when peak pressure occurs
(3) 2 to 5 second typical for pressure to build
(4) More than 5 seconds with pressure build required to capture peak
Determine the injector number 2 test rail pressure and the injector number 2 test engine speed (where the peak pressure was selected). Typically, pressure will start building after 2 to 5 sec and then there should be
sampling for 5 more seconds. Illustration 7 shows an example of selecting the peak pressure andcorresponding speed.
3.
Calculate the speed change of the injector number 2 test as follows:4.
Injector number 2 test speed change equals injector number 2 test engine speed minus pump test engine speed.
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Determine injector number 2 pressure correction using the injector number 2 test speed change and table 5.This will correct for pressure change as speed changes.
5.
Injector Pressure Correction Based on Speed Change
If injector number 2 test engine speed is lower than pump test engine speed, then correct the injector number 2 pressure by adding the correction as follows:
6.
Injector number 2 corrected pressure equals injector number 2 test pressure plus injector number 2 pressure
correction.
If injector number 2 test engine speed is higher than pump test engine speed (as can happen when a battery booster is used) then correct the injector number 2 test pressure by subtracting the pressure correction as follows:
7.
Injector number 2 corrected pressure equals injector number 2 test pressure minus injector number 2 pressure correction.
Calculate injector number 2 leakage ratio as follows:8.
Injector number 2 leakage ratio equals injector number 2 corrected pressure divided by pump test Rail pressure.
If the Injector number 2 leakage ratio is less than 0.85, the injector needs to be replaced, if the injector leakage is greater than 0.85 the injector is ok.
Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic Unit Injector Number 3 Leakage" ".
Measure Electronic Unit Injector Number 3 Leakage
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Remove the cap from cylinder number 3 and reconnect the existing fuel line. Refer to illustration 8.1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" whilecranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Determine the injector number 3 test rail pressure and the injector number 3 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
3.
Calculate the speed change of the injector number 3. Use the same procedure as the procedure in ""MeasureElectronic Unit Injector Number 2 Leakage" ".
4.
Determine injector number 3 pressure correction. Use the same procedure as the procedure in ""Measure
Electronic Unit Injector Number 2 Leakage" ".
5.
Calculate injector number 3 leakage ratio. Use the same procedure as the procedure in ""Measure ElectronicUnit Injector Number 2 Leakage" ".
6.
Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic
Unit Injector Number 5 Leakage (if applicable)" ".
Measure Electronic Unit Injector Number 5 Leakage (if applicable)
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Remove the cap from cylinder number 5 and reconnect the existing fuel line. Refer to illustration 9.1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" whilecranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Determine the injector number 5 test rail pressure and the injector number 5 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
3.
Calculate the speed change of the injector number 5. Use the same procedure as the procedure in ""MeasureElectronic Unit Injector Number 2 Leakage" ".
4.
Determine injector number 5 pressure correction. Use the same procedure as the procedure in ""Measure
Electronic Unit Injector Number 2 Leakage" ".
5.
Calculate injector number 5 leakage ratio. Use the same procedure as the procedure in ""Measure ElectronicUnit Injector Number 2 Leakage" ".
6.
Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic
Unit Injector Number 6 Leakage (if applicable)" ".
Measure Electronic Unit Injector Number 6 Leakage (if applicable)
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Remove the cap from cylinder number 6 and reconnect the existing fuel line. Refer to illustration 10.1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" whilecranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Determine the injector number 6 test rail pressure and the injector number 6 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
3.
Calculate the speed change of the injector number 6. Use the same procedure as the procedure in ""MeasureElectronic Unit Injector Number 2 Leakage" ".
4.
Determine injector number 6 pressure correction. Use the same procedure as the procedure in ""Measure
Electronic Unit Injector Number 2 Leakage" ".
5.
Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure ElectronicUnit Injector Number 2 Leakage" ".
6.
Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic
Unit Injector Number 4 Leakage" ".
Measure Electronic Unit Injector Number 4 Leakage
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Remove the cap from cylinder number 4 and reconnect the existing fuel line. Refer to illustration 11.1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" whilecranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Determine the injector number 4 test rail pressure and the injector number 4 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
3.
Calculate the speed change of the injector number 4. Use the same procedure as the procedure in ""MeasureElectronic Unit Injector Number 2 Leakage" ".
4.
Determine injector number 4 pressure correction. Use the same procedure as the procedure in ""Measure
Electronic Unit Injector Number 2 Leakage" ".
5.
Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure ElectronicUnit Injector Number 2 Leakage" ".
6.
Remove the fuel line. Replace the cap on the fuel manifold (rail) and injector. Proceed to ""Measure Electronic
Unit Injector Number 1 Leakage" ".
Measure Electronic Unit Injector Number 1 Leakage
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If necessary, remove the discharge orifice assembly from the outlet connection for number 1 cylinder. If necessary, remove the cap from cylinder number 1 and reconnect the existing fuel line. Refer to illustration 12.
1.
Record fuel rail pressure and engine speed with the electronic service tool "Data Log Recorder" while cranking for 10 seconds.
2.
Note: Make sure that there are no connection leaks during this test as the measurement will be invalid.
Determine the injector number 1 test rail pressure and the injector number 1 test engine speed. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
3.
Calculate the speed change of the injector number 1. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
4.
Determine injector number 1 pressure correction. Use the same procedure as the procedure in ""Measure Electronic Unit Injector Number 2 Leakage" ".
5.
Calculate injector number 6 leakage ratio. Use the same procedure as the procedure in ""Measure ElectronicUnit Injector Number 2 Leakage" ".
6.
Remove components of 362-9754 Test Kit from the engine. Replace any fuel injection lines that were removed during the procedures. Refer to Disassembly and Assembly for the correct procedures.
7.
Reconnect the electronic unit injector harness connectors.8.
Test Kit Data Sheet
Fuel
Injection Pump Tests
Pump
Test RailPressure
Pump TestEngine
Speed
Minimum
Cranking Pressure
(MCP)
Service
Table 6
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