I would first check for spark when it is in the no-start mode.  You
could connect one of the spark plug wires to an old plug while it is
lying on a grounded metal surface, or just hold the HV wire from the
coil near a ground and watch for a strong spark.
   Some components of the ignition system are heat sensitive when they
start to fail (like the Hall generator).  After you turn off the engine
the "heat soak" will often warm things up more than when the engine is
running.  I had this type of Hall sensor problem recently on a Saab 900.

good luck,
Larry A.

Zach Woehr wrote:

> Hi vanagon list members.  I have a problem with my 84 westy that I am
> looking for some help with.  It will start up right away when it is
> cold or
> hasn't been run for an hour or more but if I shut down the engine for a
> short amount of time after it has been running for a while (like when
> I get
> gas or groceries) it will not start back up.  The engine turns over but
> won't fire.  The problem has been getting worse lately.  In the
> begining I
> would have to let it sit for 10-15 minutes.   Now it has to sit for an
> hour
> or more.  The only other change I've detected is that the exhaust
> seems to
> smell gassier than it used to.  Any ideas?
> Thanks,
> Zach
> 84 westfalia
>