Interesting. Makes sense. I've gone over the plenum -- that thing looks
like a squashed blintz to me -- and the runners and boots and things
pretty carefully looking for leaks and didn't find any. Well, good thing
that I have new boots and gaskets a-comin from the Bus Depot. I'll tear
that mess down and comb it over finely.

Thanks!

Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR

On 9/26/2007 5:15 PM Old Volks Home wrote:

> Only if there is a vacuum leak present in the center air plenum.
>
> Remember, the vacuum flow bypasses the throttle body to reach the plenum
> through the AAR to provide that additional air.  The AAR is essentially
> a "vacuum leak", although of a temporary nature when the engine warming
> up - and fuel mixture through the injectors is richer for the first 3
> minutes (and so it needs that air) before the ECU kicks into "Closed
> Loop" mode - about the same time the AAR closes up.
> --
> Jim Thompson
> 84 GL 1.9 "Gloria"
> 84 Westfalia 2.1 "Ole Putt"
> 73 K Ghia Coupe "Denise"
> 72 411 Station Wagon "Pug"
> oldvolkshome@gmail.com <mailto:oldvolkshome@gmail.com>
> http://www.oldvolkshome.com
> ***********************************
> On 9/26/07, *Mike Rocket J Squirrel Elliott* <camping.elliott@gmail.com
> <mailto:camping.elliott@gmail.com>> wrote:
>
>     I guess either way you do it, you're restricting the flow of air through
>     the AAR? So the result (whether by pinching the hose with pliers or
>     plugging the end with your thumb) the engine should slow down.
>
>     Is it possible for the engine to NOT slow down when cold when the
>     airflow through the AAR is blocked?
>
>     --
>
>     Mike "Rocket J Squirrel" Elliott
>     71 Type 2: the Wonderbus
>     84 Westfalia: Mellow Yellow ("The Electrical Banana")
>     74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>     KG6RCR
>
>     On 9/26/2007 4:32 PM Old Volks Home wrote:
>
>      > I've often wondered about that diagnostic/troubleshoot that
>     Bentley says
>      > about the Aux Air Valve and have felt that it was bogus.  The
>     best way
>      > how you did it - on the bench to see if it closes at all when 12
>     volts
>      > is applied.
>      >
>      > In fact the testing procedure outlined for the AAR is similar in the
>      > Type 2 68-79 Bentley and it is the same part as used on the Air
>     Cooled
>      > Vanagons and 83.5-85 Wasserboxers (I've paraphrased and corrected
>     some
>      > erroneous sub-procedures that if done the Bentley way would have
>     created
>      > a HUGE vacuum leak at the air intake elbow):
>      >
>      > "To test the AAR, disconnect its intake air hose from the AAR and
>     plug
>      > it.  Take another piece of hose of the same ID (about 1/2"
>     [12mm], about
>      > 6" in length and attach it to the AAR.  Then start the engine (the
>      > engine must be cold).  If you cover the hose (during warm-up), the
>      > engine should slow down.  After several minutes of operation, the
>     vacuum
>      > should diminish and eventually disappear almost completely.
>      >
>      > "If the AAR does not close after a reasonable period (in cold
>     weather,
>      > considerable time may be required), stop the engine.  Disconnect
>     the the
>      > electrical plug from the AAR.  Using an ohmmeter, measure the
>     resistance
>      > between the two terminals on the AAR.  The reading should be 30
>     ohms.
>      > If the ohmmeter reads infinity or the resistance is considerable less
>      > than 30 ohms, replace the AAR."
>      >
>      > Source:  Type 2 68-79 Bentley, Section 10, Procedure 4.5, page 12
>      > --
>      > Jim Thompson
>      > 84 GL 1.9 "Gloria"
>      > 84 Westfalia 2.1 "Ole Putt"
>      > 73 K Ghia Coupe "Denise"
>      > 72 411 Station Wagon "Pug"
>      > oldvolkshome@gmail.com <mailto:oldvolkshome@gmail.com>
>     <mailto:oldvolkshome@gmail.com <mailto:oldvolkshome@gmail.com>>
>      > http://www.oldvolkshome.com
>      > ***********************************
>      > On 9/26/07, *Mike Rocket J Squirrel Elliott* <
>     camping.elliott@gmail.com <mailto:camping.elliott@gmail.com>
>      > <mailto:camping.elliott@gmail.com
>     <mailto:camping.elliott@gmail.com>>> wrote:
>      >
>      >     So I'm looking at the Auxiliary Air Regulator in my 1.9L. It
>     is supposed
>      >     to bypass a little air around the throttle when cold and give the
>      >     engine
>      >     a little more pep. 12V from the fuel pump relay applied to
>     its terminals
>      >     causes that bypass to close after a couple minutes. At this
>     point the
>      >     engine can presumably get along fine without it.
>      >
>      >     So Bentley's ( 24.28) gives us a simple test to see if the
>     thing is
>      >     working: start the engine and while cold, pinch the rubber
>     hose. The
>      >     rpms are supposed to drop.
>      >
>      >     Well, they didn't so I moved to the next test: check to see
>     if the AAR
>      >     is getting 12V when the fuel pump is on, and it does.
>      >
>      >     Then to the bench: you can look through the AAR and there is
>     a disc
>      >     blocking the passage, but there is a small hole in that disc
>     which makes
>      >     it easy to blow through. When 12V is applied to the AAR, the disc
>      >     slowly
>      >     rotates so the little hole is no longer visible after a
>     minute or two
>      >     and it's hard to blow through.
>      >
>      >     So -- the AAR is fine, the hoses are fine, but pinching the hoses
>      >     doesn't drop the rpms, as Bentley's say it should.
>      >
>      >     --
>      >
>      >     Mike "Rocket J Squirrel" Elliott
>      >     71 Type 2: the Wonderbus
>      >     84 Westfalia: Mellow Yellow ("The Electrical Banana")
>      >     74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>      >     KG6RCR
>