5KTQ gas cap question

[james accordino]

--- Huw Powell <audi at mediaone.net> wrote:
> 
> > >What causes a burst of air when removing my gas
> cap on my 5KTQ? Is there
> > >remedy? TIA
> 
> if it is pressurised air *escaping* there is
> something wrong.  If it is
> air *rushing in* due to a vacuum it is working
> right, congratulations I
> haven't seen one do this for a long time...
> 
> the gas cap and tank are supposed to be sealed and
> the engine draws a
> small vacuum on them to make sure the VOC's are
> burned, not released
> into the atmosphere.  culprits if it is wrong...
> charc. canister, CC
> freq valve, lines to them, etc...

Thanks for dropping the knowledge, Huw.  I did not
know this.  Amazingly, my Dorf pickup still does this.
 482k and the CC has been doused in battery acid from
an off-road mishap.  It looks awful, the plastic is
all distorted.  89 200 does it also.  Makes sense in a
lot of ways actually, that the intake system puts a
vacuum on the fuel storage.

Jim Accordino