Date:         Sat, 15 Sep 2007 16:59:21 -0700
Reply-To:     Michael Elliott <camping.elliott@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Michael Elliott <camping.elliott@GMAIL.COM>
Subject:      Rich on side, lean the other?
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm hunting for the reason that Mellow Yellow gets about 15% poorer
mileage than other similar vans. See

http://camping.elliott.googlepages.com/poormileage

to see what I've learned so far about this 1.9L 1984 auto transmission
with only 75,000 miles on it.

One oddness I've found is that both plugs on the passenger side indicate
lean condition, while the plugs on driver's side indicate rich condition.
Where could such an asymmetry come from?

There are NO visible signs of air leaks. The intake runners don't have any
cracks, are tightened well against heads; the plenum/runner sleeves are
clean and intact; and there are NO cracks in the exhaust bits that might
cause a false-lean reading at the O2 sensor -- this is a southern
California car and we outlawed snow and salt in 1932.

This lateral mixture imbalance has me quite puzzled. I am getting little
fret marks between my eyebrows! I'm dumping in a buttload of Techron
injector cleaner in case the injectors on the lean side are packed up and
the ECU is overcompensating by running #3 and #4 rich.

But . . . and but, the overall mix at the O2 sensor indicates /lean/ on
the highway, oddly (see http://camping.elliott.googlepages.com/poormileage).

I am replacing the O2 sensor on Monday. Because.

--
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