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View Full Version : Evap purge valve



wjbell
04-11-2007, 08:31 PM
I found this site testing the evaporative purge valve connected to the charcoal canister.

http://mysite.verizon.net/vzerdcib/e34a/id7.html

Well I checked mine and from what I understand the valve is suppose to close once the engine is running not allowing any outside air from the canister. Mine is getting 12 volts to the valve but pulsates allowing a little air in about every 1/3 second. In other words about ever second it's allowing three short pulses of vacuum through.

Now if I unplug the power from it the pulses get faster and it's almost getting straight vacuum through the valve... the funny thing is, if I pull the hose and disconnect power from the valve and let the valve suck unmetered air into the engine it doesn't effect the idle of the car whatsoever with a huge vacuum leak sucking air through the open valve.

Can anyone make anything of this? Do I have such a huge existing vacuum leak that introducing another one doesn't make any difference? Or is that small enough if that was my only leak that it won't effect the engine at all?

BillionPa
04-11-2007, 11:40 PM
did you try clamping or blocking the vacuum line to the throttle and leaving the evap purge valve open to atmosphere?