Date:         Tue, 29 Jun 2004 15:43:13 -0700
Reply-To:     Michael Diehr <md03@XOCHI.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Michael Diehr <md03@XOCHI.COM>
Subject:      Re: 85 Digijet throttle switches -- information please
In-Reply-To:  <20040629221526.B08CB5B763@gollum.dreamhost.com>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

>Subject: 85 Digijet throttle switches -- information please
>
>Hey, I was trying to figure out why my Vanagon has suddenly decided to
>start idling at approximately 2100 RPM.  I /really/ wish the Bentley book
>was better about giving a diagnostic troubleshooting tree... but I've been
>going through the fuel injection system.
>
>I found that the full-throttle enrichment and idle switches aren't making
>contact, and I can't get them to make contact at all.  So, I'm looking at
>possibly/probably replacing the entire throttle assembly... but I'm not
>sure if I'm going to need that or just a couple smaller parts.

Someone, please correct me if I'm wrong, but I think the throttle
closed switch serves two purposes:
   1. it puts the Digital Idle Stabilizer in circuit
   2. it tells the ECU to cut gas if idle is over 1500rpm.

When you say "can't get them to make contact at all" do you mean they
physically don't touch the roller cam?  Or that they do move, but
don't make electrical contact.   The former is an easy fix, just
loosen the adjuster screw, move them back into position, and
readjust.  The latter --- well, I'd be very suspicious if both
switches suddenly went bad at the same time (caveat -- my 85 is an
automatic, and has two separate switches, so I may not understand
your problem).

The fact that it suddenly started idling at 2100 rpm sounds to me
more like an air leak.  I'd do this:
  1. make sure the switches didn't somehow get out of adjustment
  2. bypass the DIS by plugging the two ends together
  3. check every single vacuum hose for leaks.
  4. pay particular attention to the Auxiliary Air valve, which is
     nearly impossible to get to without removing the air box, afm,
     and throttle body.