Pressure build up in the fuel tank...!

Hi everyones...thanks to read.
My father drives a Chevrolet Astro (1987) and there's a strange pressure
build up in the tank. Every two~three days, there's a noticeable odour in
the truck and when the fuel cap is unscrewed, we can hear (and see!) the
fumes escaping out, for as long as 3~4 seconds, with a loud hissing sound!
The truck belongs to his boss so my father told him about this problem. The
mechanics that regularly repairs the cars and trucks for the company told my
father that "this happens sometimes"...that he happened to own a Ford that
were doing the same thing... and to not worry about that. I personally don't
like such answer and i always thought that the pressure inside and outside
the tank was supposed to be the same...isn't it? I don't know much about
auto mechanics, but does the fuel thank is supposed to be equipped with a
vent of some sort? And anyway,how pressure can build up like this? TIA for
any replies.

--
Alain(alias:Kilowatt)
Montréal Québec
PS: 1000 excuses for errors or omissions,
i'm a "pure" french canadian! :-)
Come to visit me at: http://kilowatt.camarades.com
(If replying also by e-mail, remove
"no spam" from the adress.)

The pressure buildup is a normal part of the emissions system operation.
The fuel smell, however is not normal. I would check for fuel leaks around
the carb under the hood. Had some work done on it lately, around the time
the smell first developed? Maybe had the fuel filters changed, something
like that? Sounds like a loose connection in the fuel line.


"KILOWATT" <kilowatt"nospam"@softhome.net> wrote in message
news:Esuvc.102063$tb4.4125795@news20.bellglobal.co m...
> Hi everyones...thanks to read.
> My father drives a Chevrolet Astro (1987) and there's a strange pressure
> build up in the tank. Every two~three days, there's a noticeable odour in
> the truck and when the fuel cap is unscrewed, we can hear (and see!) the
> fumes escaping out, for as long as 3~4 seconds, with a loud hissing sound!
> The truck belongs to his boss so my father told him about this problem.
The
> mechanics that regularly repairs the cars and trucks for the company told
my
> father that "this happens sometimes"...that he happened to own a Ford that
> were doing the same thing... and to not worry about that. I personally
don't
> like such answer and i always thought that the pressure inside and outside
> the tank was supposed to be the same...isn't it? I don't know much about
> auto mechanics, but does the fuel thank is supposed to be equipped with a
> vent of some sort? And anyway,how pressure can build up like this? TIA for
> any replies.
>
> --
> Alain(alias:Kilowatt)
> Montréal Québec
> PS: 1000 excuses for errors or omissions,
> i'm a "pure" french canadian! :-)
> Come to visit me at: http://kilowatt.camarades.com
> (If replying also by e-mail, remove
> "no spam" from the adress.)
>
>

"KILOWATT" <kilowatt"nospam"@softhome.net> wrote in message
news:Esuvc.102063$tb4.4125795@news20.bellglobal.co m...
> Hi everyones...thanks to read.
> My father drives a Chevrolet Astro (1987) and there's a strange pressure
> build up in the tank. Every two~three days, there's a noticeable odour in
> the truck and when the fuel cap is unscrewed, we can hear (and see!) the
> fumes escaping out, for as long as 3~4 seconds, with a loud hissing sound!
> The truck belongs to his boss so my father told him about this problem.
The
> mechanics that regularly repairs the cars and trucks for the company told
my
> father that "this happens sometimes"...that he happened to own a Ford that
> were doing the same thing... and to not worry about that. I personally
don't
> like such answer and i always thought that the pressure inside and outside
> the tank was supposed to be the same...isn't it? I don't know much about
> auto mechanics, but does the fuel thank is supposed to be equipped with a
> vent of some sort? And anyway,how pressure can build up like this? TIA for
> any replies.
>
> --
> Alain(alias:Kilowatt)
> Montréal Québec
> PS: 1000 excuses for errors or omissions,
> i'm a "pure" french canadian! :-)
> Come to visit me at: http://kilowatt.camarades.com
> (If replying also by e-mail, remove
> "no spam" from the adress.)
>
>
I would suspect the charcoal canister under the hood , and/or hoses going to
same .

On Thu, 3 Jun 2004 2333 -0400, "Tim Kettring"
<tim6kettring@e-garfield.com> wrote:

>"KILOWATT" <kilowatt"nospam"@softhome.net> wrote in message
>news:Esuvc.102063$tb4.4125795@news20.bellglobal.c om...
>> Hi everyones...thanks to read.
>> My father drives a Chevrolet Astro (1987) and there's a strange pressure
>> build up in the tank. Every two~three days, there's a noticeable odour in
>> the truck and when the fuel cap is unscrewed, we can hear (and see!) the
>> fumes escaping out, for as long as 3~4 seconds, with a loud hissing sound!
>> The truck belongs to his boss so my father told him about this problem.
>The
>> mechanics that regularly repairs the cars and trucks for the company told
>my
>> father that "this happens sometimes"...that he happened to own a Ford that
>> were doing the same thing... and to not worry about that. I personally
>don't
>> like such answer and i always thought that the pressure inside and outside
>> the tank was supposed to be the same...isn't it? I don't know much about
>> auto mechanics, but does the fuel thank is supposed to be equipped with a
>> vent of some sort? And anyway,how pressure can build up like this? TIA for
>> any replies.
>>
>> --
>> Alain(alias:Kilowatt)
>> Montréal Québec
>> PS: 1000 excuses for errors or omissions,
>> i'm a "pure" french canadian! :-)
>> Come to visit me at: http://kilowatt.camarades.com
>> (If replying also by e-mail, remove
>> "no spam" from the adress.)
>>
>>
>I would suspect the charcoal canister under the hood , and/or hoses going to
>same .
>
>


Good Point.

Could a faulty gas cap be cause excessive pressure build up. It's not
venting when it should?

later,

tom




***************** Check Us Out *****************
http://www.CarFleaMarket.com
Bringing back low-cost online car ads to the web!

If the system is holding pressure, then that is good .. it is supposed to.
Gas caps aren't supposed to vent anymore .. even a little.

Under what conditions do you smell the fuel? Do you smell it from inside
the car, or outside the car? Can you smell the fuel inside the car without
running the A/C or heater fan? Do you smell it under the hood? Have you
climbed under the car and looked around for any signs of fuel leaking? Have
you opened the hood and looked for signs of fuel leaking from around the
carb and fuel lines?

If a gas cap vents, then it is defective and should be replaced.

> Good Point.
>
> Could a faulty gas cap be cause excessive pressure build up. It's not
> venting when it should?
>
> later,
>
> tom
>
>

Thanks a lot for the replies. I did found and read the following document:
http://www.autoshop101.com/forms/h62.pdf so i do now have a better idea of
what this system consist of. My father did read the reply and he also said
that the fuel tank was replaced two weeks before this problem started. It
may be related...maybe not. The smell happens even when the blower doesn't
operate (summer is coming soon and there's no need to run the heater,now
:-)) Under the truck or under the hood, no leaks visible. Curiously, when
there's this smell of fuel, it's more noticeable inside the truck! I'll keep
in touch since this truck is supposed to go to the annual inspection in a
few days. I'm curious about what they may find when my father will tell them
about this problem...

--
Alain(alias:Kilowatt)
Montréal Québec
PS: 1000 excuses for errors or omissions,
i'm a "pure" french canadian! :-)
Come to visit me at: http://kilowatt.camarades.com
(If replying also by e-mail, remove
"no spam" from the adress.)

Always look at the most recent work done to find the problem .. first.
Don't rule anything else out, but start there. So I'd be looking at the gas
tank and associated lines really closely. Good luck and don't be smokin'
inside until you figure it out.


"KILOWATT" <kilowatt"nospam"@softhome.net> wrote in message
news:iF7wc.131997$tb4.4772190@news20.bellglobal.co m...
> Thanks a lot for the replies. I did found and read the following document:
> http://www.autoshop101.com/forms/h62.pdf so i do now have a better idea
of
> what this system consist of. My father did read the reply and he also said
> that the fuel tank was replaced two weeks before this problem started. It
> may be related...maybe not. The smell happens even when the blower doesn't
> operate (summer is coming soon and there's no need to run the heater,now
> :-)) Under the truck or under the hood, no leaks visible. Curiously, when
> there's this smell of fuel, it's more noticeable inside the truck! I'll
keep
> in touch since this truck is supposed to go to the annual inspection in a
> few days. I'm curious about what they may find when my father will tell
them
> about this problem...
>
> --
> Alain(alias:Kilowatt)
> Montréal Québec
> PS: 1000 excuses for errors or omissions,
> i'm a "pure" french canadian! :-)
> Come to visit me at: http://kilowatt.camarades.com
> (If replying also by e-mail, remove
> "no spam" from the adress.)
>
>