Clearest picture of it is on 24.23:  "Auxiliary air regulator"

on 24.28 they tell you how to test it by pinching the hose.

On Sun, Jun 19, 2011 at 7:32 PM, Rocket J Squirrel <
camping.elliott@gmail.com> wrote:

> **
> Can anyone point me to the Bentley pages referencing this thingy?
>
> On Sun, 2011-06-19 at 18:14 -0400, pickle vanagon wrote:
>
> The only other thing that comes to mind is the aux air valve.
>
> This is the little valve that is supposed to be open when the engine is cold
> letting in extra air, and then close as it warms up.  It has a plug that
> goes into it as well, that powers a heating element.
>
> The spring in yours might be worn out, or maybe the valve "door" itself is
> gunked up and stuck in place.
>
> I don't think these can be purchased new anymore in the Vanagon part number,
> but I think they are interchangeable across old VWs (jettas, busses,
> whatever).  [warning: I'm embarrassed to say that I know from experience
> that it is easy to overtighten the locking nut on the the adjustment screw
> and break off the screw.]
>
>
> But, on the other hand, your aux air valve could be fine, in which case this
> is going to add another variable that you'll be fiddling with trying to get
> in the right balance with the idle screw setting.
>
> Good luck!
>
> On Sat, Jun 18, 2011 at 12:43 PM, John Lauterbach <jhlauterbach@bellsouth.net> wrote:
>
> > Cold start problem definition:  Engine temperature and air temperature
> > around 70-75 degrees Fahrenheit.  Start engine w/o foot on accelerator
> > pedal.  Engine starts and goes to around 800 rpm (instrument panel
> > tachometer).  If slight pressure put on accelerator pedal to take rpm to
> > 1500 or so, and then pedal released, rpm drops to around 300 and engine
> > tried to stall and then picks up speed and then tries to stall.  Slight
> > pressure on accelerator pedal for a couple of minutes or so, solves the
> > problem.
> >
> > Here is what I have done:  New within the past two weeks are new
> > O2-sensor, new Temp II sensor, and new plugs.  A couple of months ago, I
> > put in new rotor and cap.  Timing is just ahead of the mark.  I am also
> > working with backup ECU and I have cleaned the contacts on large cable
> > going into ECU.  I have checked for vacuum leaks and replaced suspect
> > hoses and fittings.
> >
> > Engine is Boston Bob rebuild that I installed in September 2003.  Has
> > about 40,000 km on odometer.  Just about everything I could buy
> > new/rebuilt at that time such as distributor and AFM went was replaced
> > at that time.  A few years ago, I installed a rebuilt throttle body.
> >
> > Recommendations on next steps would be appreciated.
> >
> > John
> >
>
>