How does purge(regeneration) valve work? - PeachParts Mercedes-Benz Forum

okc329 · #1 07-14-2007, 05:45 PM

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.

Arthur Dalton · #2 07-14-2007, 05:58 PM

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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.

okc329 · #3 07-15-2007, 10:44 AM

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.

okc329 · #4 07-15-2007, 10:47 AM

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

Arthur Dalton · #5 07-15-2007, 10:58 AM

Quote:

Originally Posted by okc329

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.

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 ????