Bad oxygen sensor ?

[Edmond]

So what do you tune by if not the o2 sensor ? SOTP ? 1/4 mile times ? MPH at
the end of the quarter ?

----- Original Message -----
From: <timsiford at hushmail.com>
To: <gmecm at diy-efi.org>
Sent: Wednesday, November 08, 2000 10:50 AM
Subject: Re: Bad oxygen sensor ?


> First the standard O2 disclaimer....
>
> Tuning by O2 voltages can be highly inaccurate.
>
> With that said ... I would check two things...
> 1) Tape a Fuel Pressure guage to your windshield and have a buddy sit in
> the passenger seat as you do a WOT run.  Have him watch the FP guage
ESPECIALLY
> in 3rd gear to see if your FP is decreasing.
> 2) Check your header collectors.  In some cases high speeds can act to
force
> fresh air into the collectors if they are not tight.  The extra O2 will
> register on the O2 sensor.
>
> Tim
>
> At Wed, 8 Nov 2000 09:59:08 -0800, "Edmond" <euro at lvcm.com> wrote:
>
> >
> >
> >I did several 1/4 mile runs after I installed my Edelbrock headers and
> >=
> >brand new o2 sensor. First and second gear are nice smooth 900mV range
> >=
> >ramps. Once it hits third gear is starts descending rapidly to about
> >=
> >400mV and stays down until I let off the throtle. I wish I was at home
> >=
> >so I can show you the exact Diacom graph. I tried giving it more fuel
> >=
> >(almost 95 in the VE tables) between 90-100 KPA but it still does this.
> >=
> >The engine runs fairly well at WOT, but I cant really tune it w/out
> >=
> >gettting some accurate info from the sensor. My old 80K mile o2 sensor
> >=
> >in the exhaust manifolds didnt do this at all. Could this indicate a
> >bad =
> >sensor ? I should mention at idle it goes from 40-50 to 800-900 almost
> >=
> >every 1/2 second. It does this at light cruise too. Maybe it's time
> >for =
> >a heated sensor ? Still downt explain the WOT weirdness though since
> >it =
> >should be nice and hot.
> >
> >
> >
> >p.s. I know Bruce already answered this on the thirdgen.org message
> >=
> >board, but I wanted some more opinions :)
> >
> >

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