Date: Wed, 26 Sep 2007 17:15:32 -0700
Reply-To: Old Volks Home <oldvolkshome@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Old Volks Home <oldvolkshome@GMAIL.COM>
Subject: Re: An Auxiliary Air Regulator puzzle
In-Reply-To: <46FAF243.1020009@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
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
http://www.oldvolkshome.com
***********************************
On 9/26/07, Mike Rocket J Squirrel Elliott <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>
> > http://www.oldvolkshome.com
> > ***********************************
> > On 9/26/07, *Mike Rocket J Squirrel Elliott* <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
>
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