Return of the diy_EGOmeter (YES, it's finally ALIVE!!)

[wattsg]

The nice little meter we have over here in Oz just uses a NS dot/bar driver
into some leds.  It's purpose isn't to give you a smog check, or to help you
tune your car to stoich.  It's only use is to give you a relative
indication, and the zero-point varies depending on EGT etc etc etc.

So the sensor that's used (which is normally the factory one fitted to the
car) is a 1-wire sensor (sometimes with heater).

I personally use mine solely for warning me when it starts to get a bit lean
under boost, and just to keep an eye on things.  It's cool to see the ECU go
closed-loop too :)

geoff

-----Original Message-----
From: owner-diy_efi at efi332.eng.ohio-state.edu
[mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of
garfield at pilgrimhouse.com
Sent: Thursday, April 16, 1998 9:12
To: diy_efi at efi332.eng.ohio-state.edu
Subject: Re: Return of the diy_EGOmeter (YES, it's finally ALIVE!!)


On Thu, 16 Apr 1998 07:45:27 +-1000, "A.HOLLEY" <holley at zeta.org.au>
wrote:

>Dont know how to tell you people this , but there is a kit available from
one of the local electronics chains here in Aus of a very similar device.
>Comes with PCB and all components except case and EGO sensor.
>Fitted one in my XJS Jag about a yr ago.
>Works like a charm. And all for $15 Aus.

Golly, is there a lotto in Oz? Cuz if you got one of them circuits,
which is dollars-to-donuts a O2 sensor voltage to LED/whatever meter
circuit, to "work like a charm" for ya, you need to go down to the lotto
office RIGHT NOW, and get some tickets!

That company, BTW, (does the name Dick Smith ring a bell?), if it's the
major one I'm thinking of, is a major boon to you aussies; electronics
experimentation and kit building like they support has long since died
in the US. I was overjoyed to get my first catalog from them (yes, they
will take phone orders...I've done it, so it's no speculation...long
distance from the US and NOT waste your time on the phone), they handle
the monetary exchange just fine, and will put you on their catalog/flyer
mailing list, all the way from OZ !! I kid you not. They even have
serious, state-of-the-art radio receivers in kit form, you'd not find
ANYWHERE in the US.

But as far as an "equivalent" O2 meter for real, "well Virginia", as we
say in the states, "...". It's not their fault. It was the best ANYBODY
could do, reading the O2 sensor voltage directly from a conventional
lambda sensor element, and trying to do something reasonable with it.
Every aftermarket company like MSD followed suit, but THEY charged you
$200 for something you could have built for $15 in parts, had you known
what was in it.

Well, now the neat thang is you CAN build one like a kit, only costing a
few bucks more (course the O2 sensor's still a tad pricey, heh), and can
REALLY use it as a measurement device. This isn't due to clever
circuitry/wizardry, so much as it's due to this new technology of
current-pump-mode 5-wire sensors.

As a talisman on the viability of this $15 wonder from the land of Oz,
just riddle me this; is the sensor it uses, 1-wire, 2-wire, 4-wire, or
5-wire. If it's anything but the last, and only costs $15 to build, it's
a myth the likes of Sisyphus.

Garfield the Septic Skeptic (refering to my vile viral guests, of
course)

P.S. Have you ever had your smog check station check the AFR numbers you
read on your Jag's O2 meter? Not getting on yer case, AH, just wondering
what your level of experience with these thangs is. Call me snoopy.