Steve, it is probably worth a mention that these tanks are not a trouble
prone item. They are not subject to engine heat. Most owners can go through
a series of Vanagons in their lifetimes and never know the things are
there--unless there is a leak, which 99 times out of 100 is going to be at
a replaceable rubber grommet or cracked hose. My diesel westy has 400K
miles on it and I have replaced the hoses and grommets but not had to touch
the tanks. I don't know a single Vanagon driver out of the many I know of
who has had a problem with them. That said, since they do hold gasoline (or
diesel) from time to time, when and if they do leak you must do something
about it. But they are not the kind of part you need to keep looking over
your shoulder about like, as you mentioned, ECUs or throttle bodies.

The fact that they are only being made in small quantities by hand supports
what I am saying, I think. If they were a significant point of failure
someone would be popping them out of molds right now.

Jim

On Mon, Aug 26, 2019 at 10:13 AM Steve Williams <sbw@sbw.org> wrote:

> On 8/25/2019 12:54 PM, WILLIAM WITZ wrote:
> > I don't know if you saw this on the Samba but this is a Good Post on
> Vapor/ Expansion Tanks system..
>
> Bill, thanks for following up with the link to Intrepid Overland's
> article on the evaporative canister:
>
> https://intrepidoverland.com/eec-aka-the-charcoal-canister/
>
> Lots of good detail there.  The article explains the canister is not a
> wear item, but a relatively complex system purges the collected fuel
> vapor using air flow produced by intake vacuum, only when the throttle
> is above idle.  It says quirks in that system can cause idle surging and
> hard hot starts, mostly due to a worn throttle body.
>
> Well worth reading the whole article.  Thanks again!
>