I think I may have an intermittent issue with the Evap system on my 1995 caprice. Occasionally I will get a hissing sound when I unscrew the gas cap to refuel. I assume this is a negative pressure hiss since I do not smell fuel, but it could be positive pressure. Is it possible this condition is normal? I do not have a CEL on.
Thanks,
Andrew
RedandBlack
Posts : 564 Join date : 2016-01-19
Subject: Re: Evap system Tue Oct 29, 2019 3:19 pm
Very common if you have low fuel.
Fred Kiehl
Posts : 7283 Join date : 2009-11-13 Age : 76 Location : Largo, FL 33774
Subject: Re: Evap system Tue Oct 29, 2019 7:13 pm
That is normal.
68JCode
Posts : 71 Join date : 2017-11-03
Subject: Thanks! Wed Oct 30, 2019 1:56 pm
I never would have guessed this to be a normal condition. I suppose you must maintain a little negative pressure to avoid letting vapors out, but this seems like a lot!
One less thing to worry about!
Thanks,
Andrew
monwell
Posts : 58 Join date : 2018-06-25
Subject: Re: Evap system Fri Jan 17, 2020 12:42 am
You should be fine. The hissing sound is justthe excess pressure.
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Tue Oct 29, 2019 2:48 pm
