Bad oxygen sensor ?

[Edmond]

Hmm...   maybe I should connect the knock sensor back up too. Right now I
have it bypased with a 3.9k resistor. (my old engine had a bad wrist pin and
it was knocking like crazy effectively killing WOT performance).


----- Original Message -----
From: "Len Sabatine" <sabatine at epix.net>
To: <gmecm at diy-efi.org>
Sent: Wednesday, November 08, 2000 2:35 PM
Subject: Re: Bad oxygen sensor ?


>    Monitor Fuel Pressure , Read Spark Plug Coloration.  MPH Trap speed  is
> indicative
>    of HP [ Consistent with prevailing weather / track conditions.
> Dependance on O2 sensor
>    readings are  risky and unreliable as a tuning  tool. [ Hear an Echo
? ].
>    Inlet - Exhaust tract leaks , FP volume / delivery and restrictive fuel
> filters are major
>    concerns. Defective chassis - engine block grounds can be an additional
> headache.
>    Len
>
> >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 :)
> > > >
> > > >
> >
>
>---------------------------------------------------------------------------
-
> >To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> >in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>
> --------------------------------------------------------------------------
--
> To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>

----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org