Date:         Fri, 10 Apr 2009 14:46:13 -0700
Reply-To:     mark drillock <mdrillock@COX.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         mark drillock <mdrillock@COX.NET>
Subject:      Re: FI harness help needed
Comments: To: Greg Potts <greg@POTTSFAMILY.CA>
In-Reply-To:  <49DFB2B8.6090607@pottsfamily.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

The white/green is not it. The white/green is there to connect the A/C
compressor clutch signal to the idle control unit so it knows when to
speed up the idle for the A/C.

The thick and stiff green wire is the one for the O2 sensor. It is coax
so great care must be taken with it. The center wire inside must not
touch the braided shield wire that is layered around it inside the outer
insulation.

Mark

Greg Potts wrote:
> Hi Volks,
>
> One of my projects today was to install a new O2 sensor on my van and
> hook it up to one of Ken Lewis' sensor feedback widgets.
>
> Step 1: Fish the wire through from the engine bay and install the sensor
> in the dash with power. DONE.
>
> Step 2. Hook it up to the wiring harness at the sensor, to test the old
> sensor before removing it.  DONE.
>
> Step 3. Power up the sensor gadget and see what happens. It reads fully
> rich, indicating there is no power coming from the sensor. OK; I kinda
> figured the sensor was dead to begin with anyway.
>
> I swapped in my new sensor; same result, even after warming the engine
> for several minutes.
>
> So I checked the heater wires to the sensor, and discovered it isn't
> getting power. Chasing the leads upstream, the original wiring harness
> has been hacked. Under the electrical tape covering the splices it looks
> like none of the wires were actually connected. Alongside the wires
> leading to the 3/4 injectors I have 4 wires available to work with;
> white, brown, white/green and a thicker gauge green wire.
>
> My vanagon is an 87 running original digifant FI and 2.1 cooling system
> on a 1.9L block.
>
> My Bentley tells me the white and brown supply power to the O2 sensor.
> No Problem there.
>
> But Bentley DOESN'T tell me what wire goes to the O2 sensor. From the
> mess I pulled apart, it initially looked like the thick green wire was
> the right one to use. That doesn't seem to work; it kills all the lights
> on the sensor feedback device and the engine idles very poorly.
>
> Running the white/green wire seems to work better, but after a few
> moments the idle drops and the widget goes back to reading low voltage.
>
> If someone can help me find the right wire to connect to the feed from
> the O2 sensor I'd really appreciate it.
>
>
> Happy Trails,
>
> Greg Potts
> 1973/74/79 Westfakia "Bob the Tomato"
> 1987 Wolfsburg Weekender Hardtop
> www.busesofthecorn.com
> www.pottsfamily.ca
>