Ken and Mark,

The problem with the throttle body is quite different from the problem with
worn bushings on a carburator. What typically happens with a carburator is
the bushings on the butterfly plate shaft wear out resulting in an air leak
and a too-lean mixture. This is easily fixed by rebushing the shaft. What
happens on the 2.1l throttle body is the throttle plate wears grooves into
the inside of the throttle body. When this happens the plate no longer seals
properly when closed resulting in excess idle air. (Normally, the idle air
screw controls how much metered air gets past the throttle plate at idle.)
When the wear becomes severe enough, the throttle plate does not always
return to the same position when closed playing havoc with idle and
driveability because the throttle position switch behavior becomes
inconsistent.

-Mark

>From: Kenneth D Lewis <kdlewis@juno.com>
>To: transporter99@hotmail.com
>CC: vanagon@GERRY.VANAGON.COM
>Subject: Re: rebuilding throttle body
>Date: Fri, 18 May 2001 19:47:47 -0400
>
>Mark;
>         I have wondered about this myself. Have you done any research on
>the subject? I remember reading, years ago, about a fellow who re-bushed
>the butterfly shaft on old SU carburetors. I will try and search the web.
>
>
>Good Luck and Drive Safely
>Ken Lewis
>86 Crewcab,60 356
>http://Neksiwel.20m.com/
>
>On Thu, 17 May 2001 18:39:45 -0400 Mark McCulley
><transporter99@hotmail.com> writes:
> > Anyone have any experience rebuilding a throttle body for the 2.1l
> > engine?
> > I've come to the conclusion that mine is pretty much shot after 120K
> > miles.
> > The butterfly valve has worn grooves on the inside of the body such
> > that
> > there is an air gap around the perimeter of the valve and a lot of
> > slop
> > along the axis of the pivot rod. The result is an inconsistent idle
> > and
> > problems setting the throttle position switch because the valve does
> > not
> > always return to the same position. This seriously affects
> > driveability of
> > the van around town (still runs great on the highway).
> >
> > How would one fix these problems? Fill in the grooves with JBWeld
> > and sand
> > smooth?
> >
> > New throttle bodies are $515.00 at Camelback and it's going to be
> > hard to
> > find a used one with low miles.
> >
> > Mark McCulley
> > Seattle WA
> > _________________________________________________________________
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