Bill,
  Go to your local hardware store.  They should have a gauge used for
measuring liquid pressures that will measure up to about 100 psi for under
ten dollars. Buy a brass 5/16" hose fitting to install on the end of the
gauge and also buy two hose clamps (one to attach hose to the fitting the
gauge and the other to attach the hose to the "T" fitting in the fuel line.
All of this can be purchased and assembled for less than ten dollars and will
be quite serviceable.  I was having trouble with my 87 Wolfsburg and I used
this setup to check my fuel pressure regulator. It was performing as it
should.  I found the problem to be a loose solder joint on the daughter board
in the ECU.  After purchasing a fine point soldering iron for seven dollars
at Walmart I was able to make the necessary repairs and solve the problem.
Good Luck.

Rico Dagastino
Munford, TN.
87 Wolfsburg
(my son drives the 84 GL which was my first Vanagon and fourth VW)