Terminal 19 on the ECU is the ground wire for the O2 wire's outer
sheath.  It provides the sheild needed for the low voltage signal put
out by the O2 sensor.  It grounds to the left head and is bundled (and
branches off) the same bunch of wires going under the intake to the
Hall sender.  As you mentioned, if you take the ECU connector off you
should be able to find your ground using a continuity test.  I am
surprised yours is connected to the wall under the coil since that
wire (in original format) is too short to reach that far.

- Laurence

----------------------------------------
 Laurence Smith
 Hamilton, Ontario, Canada
 90 Westy / 90 Subie 2.2 (in progress)
 87 GL / 91 Subie 2.2
----------------------------------------

> -----Original Message-----
> From: Vanagon Mailing List
> [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of Jim Morgan
> Sent: Tuesday, February 17, 2004 10:08 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Left head ground
>
>
> Greetings all.
> I have a question concerning the l head ground. As I
> understand it this is
> the ground
> that the ECU uses for richness? I have found in the archive
> that if this
> ground is not
> grounded properly it will run rich.
>  I do not have this ground on the head. What I do have is a
> grounded wire
> going to the group of grounds unde the coil.
> Now my question how can I find out which one of the grounds
> belongs on the
> head?
> Does this ground have a number on the ECU plug? If so I can
> just use a
> continuity
> tester on ECU plug number and just check each wire
> individually. Is this a
> reasonable procedure? if so would anyone now the number on
> the ECU plug?
>
> Jim Morgan 86 Gl
> 210,000.0 "bread box"
> Westlake,Ohio
> jm060356@aol.com
>