Date:         Thu, 20 May 2004 00:43:03 -0400
Reply-To:     Laurence Smith <laurence@ALANASMITH.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Laurence Smith <laurence@ALANASMITH.COM>
Subject:      Re: Significance of the o2 sensor
Comments: To: JNMOTLAG@SPRINTPCS.COM
In-Reply-To:  <0HXZ00HKIIOYIQ@boded0198snunx.wh.sprintip.net>
Content-Type: text/plain; charset="US-ASCII"

To test the O2 sensor get the engine warmed up and then with a
voltmeter touch the red + positive to the green O2 wire and the
negative to a ground point on the engine.  Don't disconnect the O2
green wire - just pull back the rubber protector a little.  The
voltage reading should jump back and forth at 0.5 volt +/- 0.3 volts
if fuel injection system is working well.

Make sure the brown ground wire on the engine (under the intake,
attached to the head, driver's side) is well connected.  This is the
ground for the O2 sensor sheild.  If this is bad the ECU will get
erroneous signals from the O2 sensor (even though the O2 sensor is
working okay) and the ECU will make the engine run rich.  To
demonstrate the impoortance of this wire you could try disconnecting
it and you'll the lovely pillowing of black smoke as the engine goes
super rich.

- Laurence


----------------------------------------
 Laurence Smith
 Hamilton, Ontario, Canada
 90 Westy / 90 Subie 2.2 (in progress)
 87 GL / 91 Subie 2.2
 (given up on 2.1 wasserleakers)
----------------------------------------




> -----Original Message-----
> From: Vanagon Mailing List
> [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of John N. Motlagh
> Sent: Wednesday, May 19, 2004 7:30 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Significance of the o2 sensor
>
>
> I have an 86, with 12k on a rebuilt Boston Bob engine, I
> just did my 1st
> major service, plugs, wires, 20w50 synthetic, mann filter,
> new belts, new
> fuel filter, air filter, cap and rotor, and then timed it
> with a light gun.
> Just before the service I was getting about 125-150 miles
> out of a tank, and
> it is no better after.
>
>
>
> I am guessing that I am running rich.  Upon review of the
> archives, all
> signs point to the o2 sensor as the culprit.  I took it
> out, it is a little
> grey, there is some soot around the base.
>
>
>
> Is there a way to test it on the vehicle?  Is there way to
> adjust the
> fuel/air mix?  How do I know I have it right?  What are the
> consequences of
> taking it out, plugging the hole and tie wrapping the
> sensor to the frame?
>
>
>
> Regards,
>
>
>
> John N. Motlagh
>
> 1986 East Texas Westy
>