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 Evap system

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68JCode




Posts : 71
Join date : 2017-11-03

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PostSubject: Evap system   Evap system Icon_minitimeTue Oct 29, 2019 2:48 pm

Good afternoon everyone,

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
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RedandBlack

RedandBlack


Posts : 564
Join date : 2016-01-19

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PostSubject: Re: Evap system   Evap system Icon_minitimeTue Oct 29, 2019 3:19 pm

Very common if you have low fuel.
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Fred Kiehl

Fred Kiehl


Posts : 7290
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Evap system   Evap system Icon_minitimeTue Oct 29, 2019 7:13 pm

That is normal.
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68JCode




Posts : 71
Join date : 2017-11-03

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PostSubject: Thanks!   Evap system Icon_minitimeWed 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
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monwell




Posts : 58
Join date : 2018-06-25

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PostSubject: Re: Evap system   Evap system Icon_minitimeFri Jan 17, 2020 12:42 am

You should be fine. The hissing sound is justthe excess pressure.
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PostSubject: Re: Evap system   Evap system Icon_minitime

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