Date:         Mon, 3 Aug 1998 12:11:46 -0400
Reply-To:     William Dummitt <williamd@COMPUSERVE.COM>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         William Dummitt <williamd@COMPUSERVE.COM>
Subject:      Re: Idle at start problem
Comments: To: vanagon list <vanagon@vanagon.com>
Content-Type: text/plain; charset=ISO-8859-1

....snip.....
>My 86 runs great, no complaints, except . . . when first started, unless

>it's fed a little gas (for about 15 seconds) it'll die. Once it's warm
>and running, no problem.  More of a nuisance than a problem, but I would

>like to correct.  Any ideas?
...snip

I'm betting on a bad throttle position switch.  This is a little switch
underneath the throttle body that tells the ecu when the engine is at idle
or full throttle.  The way it works is a cam that pushes a switch in at the
idle and full throttle positions and leaves the switch open otherwise.  The
ecu then slightly enriches the mixture when the switch is closed.  


I first discovered how important this switch was when I got Darrell
Boehler's digifant tool (discussed frequently on the list in recent weeks).
 Four of the first five vans I checked had bad throttle position switches,
and all idled much better when the problem was corrected.  Even without
Darrell's tool, the switch is easily checked with a continuity tester-it
should show a closed circuit at idle and full throttle, no continuity
otherwise.  The plug to test is on top of the engine near the throttle,
with a wire running underneath the throttle.

Bill