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EVAP Purge Valve

  • Charles Acosta
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3 years 7 months ago #54019 by Charles Acosta
EVAP Purge Valve was created by Charles Acosta
Hello. If the PCM controls the duty cycle to purge vapors according to engine RPM, why in the diagram it has a input port vacuum. What's its purpose? I like to know. Thanks in advance.

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  • Tyler
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3 years 7 months ago #54053 by Tyler
Replied by Tyler on topic EVAP Purge Valve
You know, that's a good question. :blink: I looked over Theory and Operation in SI and couldn't get a good idea.
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3 years 7 months ago #54055 by Matt T
Replied by Matt T on topic EVAP Purge Valve
It's a pilot vacuum supply which is switched by the solenoid to operate the main valve. The large round disc the two purge lines go to contains a diaphragm which the pilot vacuum pulls against to open the main valve.

Depending on where the vacuum is sourced from it may also have some influence on controlling purge flow.
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