<snip> I'll turn the key, hear the fuel pump being primed, and turn the
key to start the engine and nothing.  <snip>

This is not all that uncommon with VW buses of all years.  However, the
causes and fixes are various.

1.    Clean all grounds ... especially the one from the body to the
transmission mount and the battery ground.

2.    Make sure all connections are clean and bright at the battery and
at the starter, including where the battery negative cable bolts to the
body.  Don't just observe the grounds and connectors .... take them
apart and really clean clean clean 'em.

3.    Check the voltage at the starter when trying to start the engine.
Sometimes an old ignition switch or the wire from the ignition to the
solenoid is the culprit.

4.    It could be that your solenoid needs to be cleaned and relubed.

5.    Some have made theirs work by installing a "Hot Start Relay" which
uses the original long run of wiring to just trigger the relay, which
should be near the starter, thus allowing the solenoid to see a greater
voltage.

Meanwhile, when you turn the key but get no starter action, put it in
neutral and have an assistant turn the key while you use a length of
broom stick to poke the solenoid through the wheel well.  I'll bet it'll
come to life .... for that moment anyway.

I've even seen where the braided cable that runs from the solenoid to
the starter motor, internally, was badly corroded and causing the
problem.

Good luck chasing that gremlin and let us know how you make out and what
worked in your case.

Mike
Houlton, Maine
'84 GL 7 pass
'85 GL Westy