Date:         Thu, 11 Sep 2003 14:10:37 -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
Comments: To: Tom Young <tomyoung1@comcast.net>
Content-Type: text/plain; charset="iso-8859-1"

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?

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?


----- 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?
>
>
>