Re: Adding another O2 sensor

["Dave Zug" <dzug@delanet.com>]

Only thing I see as a possible engineering point is that the location of the
sensor be as close to the distance from the valve that the OE location in
the stock manifold was... but you may have already assumed to do this this.
Switch 'bounce" a factor anyone?  not for long I guess - not significant.

My O2 cents.


----- Original Message -----
From: Walter Sherwin <wsherwin@home.com>
To: <gmecm@diy-efi.org>
Sent: Wednesday, November 01, 2000 6:21 PM
Subject: Re: Adding another O2 sensor


> Actually,  you have a good idea there!..........By placing one standard
zirc
> oxygen sensor at each header collector, and by running the outputs up to a
> toggle switch mounted in the cabin, you will have the ability to flip back
> and forth to determine whether the fueling is balanced from bank to bank
> (assuming you are still running bank fire).  You could then use one ALDL
> scan tool device to observe either O2 output, and make a comparison either
> while at idle or while on the road.  Would make things "nice" when
tracking
> down a bad cylinder, or injector, or combo.
>
> Now let's say you find one day that the fueling is "off" between banks,
due
> to say recent porting & runners & etc.,  and that your cylinders and
> injectors are in fine working order.  Are you then SOL for adjustability
> without reverting to elaborate sequential EFI control?  Absolutely not!
> Accel make a plug-in product called the "VIC" (short for Variable Injector
> Controller) which can offer +/- 10% BPW adjustment per injector, while
using
> your conventional bank fire ECM triggers and wiring.  It's as simple as
> twisting a knob per injector, and then locking it into position.  Kinda
like
> having SEFI, but without all the other associated hassles.  Two O2's,
> together with some plug reading and a VIC, could get you to where you need
> to ultimately be for balanced fueling.
>
> However, for the two zirc O2 bank readings to be meaningfully comparable
to
> each other, you'll want to make sure that your sensors share the exact
same
> ground plane.  With custom exhaust parts inserted in the ground path(s)
> between your sensor(s) and the ECM O2 LO sense circuitry, it would be
> prudent to either:  1)run a braided ground strap from one header collector
> to the other, OR   2)see a recent post to this list regarding standard
zirc
> O2's with redundant external ground leads built-in (GM and AC Delco P/N's
> were supplied).
>
> Carry this dual O2 concept one step further.............You could even
> purchase a couple of cheap (but useful) Halmeter AF30 O2 monitors, and
stick
> them side by each on the dash.  This would expose a huge wealth of insight
> with regards to comparative O2 trends and magnitudes between banks.  If
you
> later got "fancy", you could probably datalog the raw zirc O2 signals and
> get to the point of examining each individual cylinder event on a trend
> basis.  Although this approach would not necessarily be super accurate in
> terms of absolute A/F ratio,  it would at least be somewhat repeatable and
> illustrative for comparo purposes between cylinders.
>
>
> Walt.
>
>
>
>
> > Car = 1990 IROC-Z
> > From the factory these cars have one O2 in the driver's side exhaust
> manifold.
> >
> > Since I will be installing Hooker long tubes I have been contemplating
the
> > installation of an O2 sensor in the passenger side header as well as the
> > driver's side header.  Then, I was thinking of running a SPDT toggle
> switch
> > so that I could switch between the O2s to determine how one side of the
> > engine is running as compared to the other side.
> >
> > Just figured I would throw this out into the air since the list is
pretty
> > dead today.  Besides the obvious con of the extra expense ... can anyone
> > think of a reason not to do this (besides the whole geek factor)?  Would
> > the fact that O2s are not accurate be enough of a reason for not doing
> this?
> >  If so, then why is it that later F-bodies run an O2 sensor for each
side
> > of the engine (one for each bank of injectors).
> >
> > Heh heh - wouldn't it be cool if WB O2s were cheap and we could install
> > a WB O2 into EACH primary tube of the header and then tune each cylinder
> > for maximum power through sequential fuel injector tuning?  That would
be
> > really cool.  Yea - I know I am just wishing ... sometimes its cool to
> wish.
> >
> > Tim
>
> --------------------------------------------------------------------------
--
> To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> in the body of a message (not the subject) to majordomo@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@lists.diy-efi.org