Re: LED Fuel Mixture Meters

[Orin Eman <orin@WOLFENET.com>]

> Can these LED fuel mixture meters I keep seeing in European Car magazine
> such as the "Dynograph" by Perfomance Instrumentation be used to read
> CIS F.I. CO percent also?  Looks like they hook into the OXY sensor.  Or
> is there no substitute for a good CO meter and probe?

They just read the O2 sensor voltage.  I haven't tried one, but I have
built my own using an LM3914, 10 LEDs, a Radio Shack box and a couple
of other components.  $20 or so.

Due to the way the O2 sensor works, you will find it cycles from rich to
lean with virtually no time in the middle... some low-pass filtering
would help (time constant in the .1 to 1 second range), but that would
make the display slow to react.

So, these aren't a good substitute for a CO meter.  They will merely
tell you if you are in the ballpark - way rich, way lean or probably OK.

Orin.