Date:         Tue, 23 Dec 2003 08:21:16 -0800
Reply-To:     Dana Morphew <kadm@PUGETSOUND.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dana Morphew <kadm@PUGETSOUND.NET>
Subject:      Re: Vanagon gas mileage
In-Reply-To:  <000701c3c90d$dae626e0$6801a8c0@williamvafwvvc>

If you have a tinker's bent, and you want to test a theory:  open the AFM and
increase the spring tension a notch or two.  This will signal the ECU that
less air is flowing than is actually the case.  The same amount of air will
be flowing through the AFM, but the increased spring tension will not allow
the flap to open as wide as it normally would and the air velocity will
increase to make it up.   Another part of the equation is the oxygen sensor's
signal to the ECU.  I don't know whether the ECU meters fuel to an average of
these two readings or whether it weights one in favor of the other.

In my Digifant II I-4 conversion, I get 24-26 @ 65-70 on the freeway with my
4400 lb. Vanagon after having increased the AFM tension two notches in tandem
with a new oxy. sensor.  I've advanced valve timing 8° also, but I doubt that
has much effect on fuel economy.  Make sure all the usual items:  engine
compartment grounds, temp sensors, air filter, etc. are good.  Do not run the
engine lean without due caution.

Dana

On 22 Dec 2003 at 20:33, developtrust wrote:

> I'm envious of those that get higher gas mileage. I have a 1989 vanagon GL
> camper and just today calculated my MPG to be 13.4 and that seems low compared
> to the rest of you. I typically take short trips and when I go freeway driving
> I drive at 70 to 80 MPH in the flow of California traffic. For highway only
> traffic I get about 17 MPG.
>
> I can't help but wonder what I can do to get better mileage.
>
> William
>
>
> > In my last trip, I was averaging a gas mileage of 20 m/USG with my
> automatic
> > Westy 87 and I was wondering if I could get better gas milleage. From your
> > result, I guess my van is well tuned. However, I have never been driving
> > higher than 60 mph.
> >
> > Germain
>
> >
> > > My old '84 got 20mpg. I recently bought a "91 that's an automatic. I
> find
> > out
> > > now it only gets 16mpg. Aside from a tune -up, any ideas on how to
> > increase
> > > it?
> > >
> >
>