I found Mark's bypass harness very useful recently in evaluating the engine
in an '84 parts van that I had purchased.  I did cheat a little by getting
12v from the alternator using a large alligator clip.  The PO said that
they had not been able to get it running and the electrical was "all fouled
up".  Seeing the wiring mess in the engine compartment, I built Mark's tool
and then proceeded to replace the starter, fuel pump, distributor, (Hall
sensor), coil, and Hall control module.
  It finally ran and ran well.  Should be usable.

What fun,
Larry A.

On Thu, Oct 25, 2012 at 2:29 PM, mark drillock <mdrillock@cox.net> wrote:

> This type of problem comes up often enough that I built a wiring bypass
> tool to help track it down. The tool is meant more for situations where
> the van dies and won't start again right away or ever. The point of the
> bypass tool is to quickly eliminate most of the known wiring faults that
> happen to 2.1 wbx and keep it from running. The ignition switch will be
> used for cranking the starter but turning the key off won't stop the
> engine with the bypass tool in use. This lets you eliminate the ignition
> switch as a cause of your problem. If you fully install the tool and the
> problem doesn't happen anymore then you know that most of the fuel
> injection, ignition, and fuel supply systems are working and you won't
> waste time and money chasing guesses for what part might be bad. Then
> you can remove the 3 bypass branches one at a time to find which branch
> has the problem.
>
> http://www.thesamba.com/vw/**forum/viewtopic.php?t=349429<http://www.thesamba.com/vw/forum/viewtopic.php?t=349429>
>
> Mark
>