How does purge(regeneration) valve work?
 

I attmpting to diagnose the P0455 code problem on my '97 E320. I have replaced the gas cap but keep having to clear the code. I was examining the purge valve operation and have the following questions:

1) When does it operate?
2) Does it always pass the same vacuum strength to the components at the tank?

When I first checked mine, it was not operating. Drove the car and got it hot. I could then hear/feel the valve pulsating. I pulled off the hose leading to the rear of the car and the vacuum thru the valve seemed very weak. I jostled the valve a bit and then got a much stronger vacuum level.

Any explanation for why CEL usually pops on at a long idle, e.g. traffic signal, after a drive at highway speeds? What would be the consequences of putting a shot ow WD40 in the tank side of the valve?

TIA to responders.

<<What would be the consequences of putting a shot ow WD40 in the tank side of the valve?
>>

Nothing..that is how I recommened cleaning them out..
The valve pulses 6/7 BPM so that when it is activated, the engine does not get a large gulp of intake air that would be more than the engine could handle all at once without effecting Engine Management controls..[ ie..the ECU would read it as a lean condition vac leak b/c this air is unmetered intake air supply] ..the pulsing gets rid of that problem by letting a little in at each pulse.

Thanks, Aurthur...
 

If I understand you, the valve does not run all of the time but once it does, it runs at a steady rate to put a small amount of unmetered air into the intake.

I'll try the WD40 fix.

Arthur....
 

please excuse the my incorrect spelling of your name in the previous reply.

Yes
Every time it pulses , it opens and closes..it does this few times a sec [ htz].
so the flow is actually controlled as to not allow a big gulp of canister vapors all at once. It only does this when the ECU sends a signal to do so.

Mispeeling is fine , just don't call me "Artie"...:)

Smartie Artie was a childhhod nickname I got pinned with.
so...........Not my favorite

" Well, you can call me Ray, or ya' can call me Jay, cuz ya' doesn't hasta' call me Johnston ...."

....any '70's Beer Drinkers 'member dat one ????