lambdasond and measuring

[Walter Petermann]

Roland Johansson wrote:
> 
> I'm new to this list, found it when I was searching for
> monitoring my mixture-level. I managed to build a meter with 10
> leds after the drawings on the DIY_EFI homepage. Tuned it to
> light maximum with 1,25V insignal.
> Now my problems come, in some situations it disappers after
> beyond the 10 led. The lambdasond is new and car is running on
> leadfree gas. Can the lambdasond output higher voltages than
> 1,2V if mixture is rich? I'm running my meter in dot-mode if
> that is making false-reading.
> Is there a voltage-level that compares to some CO% reading or
> similar. I know this is not exact but if it is in nearby area is
> ok.
> Hope to get it working good.
> 
> Roland Johansson
> Scirocco 1,6l TIC -82
> Http://www.oden.se/~toker/yellow.htm (english)
> Http://www.oden.se/~toker/gulturbo.htm (svenska)

Roland,

I had the same problem a couple of days ago. I am using an
LM3914.
In my case, if the voltage input to the IC falls below 1/10
of the reference all the leds go blank. If this is the
problem you're having, the only solution I can think of
would be to add about .1 volt to your input before applying
it to the IC (in such a way that it won't effect the real
reading of the o2).

A regular o2 is just a binary device rich/lean. It can't
give much accurate information beyond that. However, there
are types of o2's with wider range and I'm sure someone in
the group will be able to give you all info on them.

 regards,
   Walter