Dan:

Injection in the early '80 air-cooleds is reasonably
simple and very reliable.  (Mine has original components
after 128,000 miles on lots of rough backroads.)

First step (always) with this kind of problem is to
perform/confirm basic tune-up parameters.

Then, if the problem is starting cold--below ~45 degrees,
check the cold-start system--a "5th injector" that zaps
gas into the common manifold.  It should inject for
10-12 seconds of cranking time, then shut off via the
thermo-time switch associated with it.  It is a pain
to work on.  Watch for brittle plastic connector covers
and such.

                                Richard A. Jones
                                '81 Vanagon  Mr Bus
                                '88 Carrera