Date:         Mon, 16 Jul 2001 07:19:36 -0800
Reply-To:     Mark Keller <kelphoto@ISLANDNET.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Keller <kelphoto@ISLANDNET.COM>
Subject:      Engine Misses
Content-Type: text/plain; charset=us-ascii

Greetings,

I've recently done a spark plug wire maintenance on my van and came
across a design change in the spark plug jacket to spark plug wire that
is essentially a possible point of failure.

In the Bentley on Page 28.30a there is a picture of the New style
ignition cables connectors.  Wouldn't you know it I have the Old style
plug jackets and the new style connectors on my cables.

I have a 91.  When I bought the van I learned that I could buy Belden
brand metallic spark plug wire from Napa and spark plug lead connectors
from VW.  I didn't notice the "change" in lead connectors when I did
this service.

Anyway I had the miss problem located to the number 1 plug wire into the
spark plug connector which has a tight radius because of the location of
the air cleaner box right on top of it.  Looking at the drawing I
concluded that since there isn't a Mechanical connection it's possible
for a gap to occur at this connection, and the fact that I was getting
an open reading on the ohmmeter. After cleaning and inspection I
discovered this fault.

The older style connection is also a weak connection in my opinion.  If
you have a miss and want to look at this, try measuring the resistance
from the disturber plug end to the inside of the spark plug connector.


The other item on misses is looking at the engine at night while it's
running and looking for stray electric sparks.  Often a plug wire case
will rub on a metal components and begin to ground at that point.  You
can SEE the tiny sparking.  Visual inspection in daylight is supposed to
be a white mark on the wire. All plug wires should be physically routed
with spark plug wire looms, those plastic things.  A real no no is wire
tying the wires together; but I do use a loosely attach plastic wire tie
on a couple of spots so that the tie acts as loom..  I like a tidy
engine, and find personally the spark plug wires on this layout to very
difficult to properly isolate from possible ground points, so be
prepared with a loom kit, plastic wire ties, and maybe even a new wire
or two as the length of the wire tends to matter.

The other miss is the lean or rich misfire. Vanagons are known for the
lean idle misfire. This is really a CO adjustment, throttle switch
adjustment, idle compensation type of fault.  Verify the mixture at warm
idle with the O2 disconnected  and look for a low volt or high volt
indication.  the range is .3 -.7 volts.  Lean LEAN is below .1 volt and
Rich RICH is above .86 volts.

Sincerely,

Mark Keller,

91 Carat
Cowichan Bay, BC