I am late coming in to this discussion but if engine cranks but does not start have you verified that the ignition switch is working? I have replaced 2 switches since I replaced the original switch last year. I have a 91 Vanagon.  
Cheers
Jaime
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On Wed, 3/30/16, Ed McLean <email99@BELLSOUTH.NET> wrote:

 Subject: Re: Engine Cranks but No Start
 To: vanagon@GERRY.VANAGON.COM
 Date: Wednesday, March 30, 2016, 12:47 PM
 
 If the voltage, measured AT THE
 BATTERY with a digital volt meter, is less
 than 10.4 volts with the starter turning the engine the ECU
 will not work
 correctly and it won't start.  The starter will,
 however, still spin the
 engine over pretty good at this voltage.  I've
 forgotten if the ECU will
 fail to produce spark or fail to activate injectors at this
 voltage
 because it was about 18+ years ago this happened to me.
 
 A simple way to check is to try a booster battery to make
 sure there is
 enough voltage.  If it starts, you probably need a new
 battery although it
 could be something wrong with your charging system.
 
 I've been thinking that maybe the tachometer will not work
 if the ECU is
 below this voltage threshold.  Check to see if the tach
 needle indicates
 the appropriate cranking speed while cranking.  If it
 is correct, you
 don't have any new information but if it doesn't indicate
 correctly you
 know that the ECU isn't working.  I don't remember what
 the tach did when
 my '86 had this problem.