Checking for leaks in the evaporative emission system
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Checking for leaks in the evaporative emission system
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1.
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The cut-off valve shall remain activated.
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2.
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Detach the line from the EVAP canister purge valve at the intake manifold.
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3.
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Raise the pressure again, following the instructions in the Kent-Moore manual.
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4.
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Use ultrasonic leak detector J41416 to trace the leak. Start with the line that has been disconnected from the intake manifold and then follow the system lines and components. Make a visual check of the system at the same time.
Note
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In order to check for leaks in components on the top of the fuel tank, it may be necessary to lower the tank a bit.
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Note
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Leak detection listening equipment is sensitive to ambient noise, such as exhaust outlet, air-driven machines, use of blower nozzles, leaking pressurised air connections, etc.
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Airflow from the ventilation equipment in the workshop can also affect the equipment.
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All of the items mentioned can cause a similar, but incorrect indication/detection of a leak in the EVAP system.
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5.
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Therefore, always adjust the sensitivity of the ultrasonic leak detector, so that the ambient noise, which often causes interference, is filtered out.
Note
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A larger leak, such as a faulty cut-off valve or a loose line, is difficult to detect as it does not give off the ”right noise” to be detected by the ultrasonic leak detector.
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For this reason, it is essential that you make a thorough visual inspection of the system components, to check for leaks not detected by the equipment.
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6.
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Rectify any leaks detected and test the system again.
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7.
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Restore the car to its normal condition.
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