Date:         Thu, 11 Sep 2003 15:35:05 -0600
Reply-To:     Chad Morris <chad@ALLMORRIS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Chad Morris <chad@ALLMORRIS.COM>
Subject:      Re: O2 readings
Content-Type: text/plain; charset="iso-8859-1"

Thanks again.  I found the post you mentioned here:
http://gerry.vanagon.com/cgi-bin/wa.exe?A2=ind0103B&L=vanagon&D=0&m=140137&P=3822

I'll give it a try.

----- Original Message -----
From: "Tom Young" <tomyoung1@comcast.net>
To: "Chad Morris" <chad@allmorris.com>
Sent: Thursday, September 11, 2003 3:03 PM
Subject: Re: O2 readings


> From: "Chad Morris" <chad@allmorris.com>
> To: "Tom Young" <tomyoung1@comcast.net>; <vanagon@GERRY.VANAGON.COM>
> Sent: Thursday, September 11, 2003 1:10 PM
> Subject: Re: O2 readings
>
>
> > Thanks, Tom.  You are correct, I did mean that I took the measurement
> > inline.  I did, however also take a measurement with the O2 sensor
> > disconnected and it measured generally about the same, between .81 and
.89
> > volts.  I will take your advice and try to correct my too rich situation
> by
> > adjusting the air/fuel mixture screw.  I am assuming I do this with the
O2
> > sensor disconnected from the ECU, correct?
>
> Yes.
>
>
> > I also remember reading something about adjusting the Air Flow Meter to
> > change lean/rich condition.  I think the manual says don't touch it, it
is
> > calibrated at the factory, but judging from the orange silicone sealing
> > around the lid of the AFM, someone messed with it before I bought the
van.
> > Do I dare go there?
>
>
> Yes.  The spring gets weak over time leading to a too-rich situation.
> Eventually even backing the adjusting screw out all the way won't lean
> things enough.  The AFM screw-tightening procedure is well documented in
the
> archives; I know I've written it up several times, and others have too.
>
>
> >
> >
> > ----- Original Message -----
> > From: "Tom Young" <tomyoung1@comcast.net>
> > To: "Chad Morris" <chad@ALLMORRIS.COM>; <vanagon@GERRY.VANAGON.COM>
> > Sent: Thursday, September 11, 2003 12:42 PM
> > Subject: Re: O2 readings
> >
> >
> > > When you say you're getting those readings on the "O2 sensor with it
> > hooked
> > > up to the ECU" I assume you mean the voltmeter is "inline" between the
> O2
> > > sensor and the ECU?  If so, re-run your test with the O2 sensor
> > > disconnected.  The O2 sensor should put out a voltage of right around
.5
> > > volts at the correct air/fuel mixture (the graph of voltage vs.
mixture
> is
> > > *very* steep right around the "ideal" mixture, so you should see a
rapid
> > > fluctuation above and below .5 volts) with higher voltage indicating
> "too
> > > rich" and lower voltage indicating "too lean."  What you're reading is
> the
> > > output of the O2 sensor, the ECU's attempts to correct, and whatever
> > > distortion you're introducing with the voltmeter.
> > >
> > > Doing the test with the O2 sensor disconnected will give you an
> indication
> > > of the basic mixture before the ECU tries to correct it.
> > >
> > > You adjust the air/fuel mixture after making sure that every other
> aspect
> > of
> > > the engine - mechanical, ignition, vacuum, etc. - is correct.
> Adjustment
> > of
> > > the air/fuel mixture screw is the first thing to try to correct a "too
> > rich"
> > > situation
> > > ---------------------------------------------------------------
> > > Tom Young                       '81 Vanagon
> > > Lafayette, CA 94549         '82 Westfalia
> > > ---------------------------------------------------------------
> > > ----- Original Message -----
> > > From: "Chad Morris" <chad@ALLMORRIS.COM>
> > > To: <vanagon@GERRY.VANAGON.COM>
> > > Sent: Thursday, September 11, 2003 10:20 AM
> > > Subject: O2 readings
> > >
> > >
> > > I am reading between .81 and .89 volts on my O2 sensor with it hooked
up
> > to
> > > the ECU.  I am thinking that indicates I am running rich.  Assuming my
> O2
> > > sensor is good, what would the ideal reading be?  If it is indeed
> running
> > > rich, should I be able to remedy that simply by turning the air/fuel
> > mixture
> > > screw, or will I need to mess with something else to get it to run
> right?
> > > Any thoughts?
> > >
> > >
> > >
> >
>
>