Date:         Fri, 26 Mar 2004 19:06:53 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: slightly oily plugs
Comments: To: "Warren.K.Lail-1" <wlail@OU.EDU>
In-Reply-To:  <14d354414ceb33.14ceb3314d3544@ou.edu>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 08:13 AM 3/26/2004, Warren.K.Lail-1 wrote:
>will replace it.  That seems to be the only
>component in my system that is not functioning
>properly.  If they're willing to do it, I will
>pay the difference and get the 02 Sensor that
>plugs right up (not the one that has to be
>wired in, like mine).
>
>I've double checked my wiring job and it looks
>okay.

Now measure what the sensor is putting out with sensor disconnected from
the ECU -- should be somewhere between about 0-.2 volts (lean) and around
.7 volts or so (rich).  If it's over a volt, you're getting leakage from
the heater leads or some such.  If not, it should vary as you play with the
throttle, and go to lean if you run it up fast and close the throttle --
because the ECU  shuts off the fuel entirely until you get below 1500
rpm.  This is much easier to see if you spin the wheels-- they'll keep
things going long enough to read the meter and you won't have to run the
engine very fast.  At the same time check the voltage on the ECU lead,
should be steady right around .5 volts.

If readings are reasonable, leave the meter hooked up and connect the
sensor to the ECU.  What happens?  If things are working right the sensor
will start flipping  back and forth btw lean and rich.  But exhaust leaks
may draw in air and make it seem lean when it's not, in which case the ECU
will richen the mixture until it overwhelms the leak.  At WOT (wide open
throttle) you should definitely see rich, because the ECU stops listening
to the sensor and richens the mix (I have seen an ECU that after running
for a while would go lean at WOT instead of rich -- resetting by shutting
off for an instant would cure it for a while.  No idea what causes that
except I presume it's an ECU problem).

If the reading goes to ground and stays there, chances are you've shorted
the sensor lead to the shield braid surrounding the wire from the
ECU.  That will make it run very rich.  (Ditto if the ECU shows 0 with the
sensor disconnected).

david


--
David Beierl -- dbeierl@attglobal.net