o2 meter

[Tom Cloud]

>> My car's ECU grounds to the intake manifold and I seem to remember
>> there was a .18V difference between there and the ECU itself.
>
>I got the o2 meter mounted now, and grounded it on one of my accessory
>circuits. The voltage difference is around .2 volts, since that is the
>LED reading w/o the engine running. The only problem is that the meter
>doesn't work! When the engine is running, the led lights from 2 to 3.
>Floored, cruise, anything! It blips up right as I shut the car off, but
>that's it. The sensor is about 5 months old, BTW. Any ideas?
>
>Andris

Andris -- should have zero volts engine off and cold and at
initial startup (unless it's heated).  Any residual voltage
is due to voltage drops from current being drawn by accessories
like headlights, heater motor, etc -- and that will obviously
change as the accessory current draw changes -- which is not,
I don't think, what you want!

The EGO that came stock on my '82 Bronco had two wires -- signal and
ground.  A new one from PepBoyz cost me about $25.  You might try using
one of those -- at least its got the ground wire connected.  I run a
digital meter on mine -- no LED's .... but then, I'm not running an
oem efi that sweeps the a:f ratio around stoich.  I've too many years
doing instrumentation to be satisfied with the crappy way many of
the sensors are connected in a typical auto.  Due to the noisy
environment (radiated and resistive) all sensors should be
two-wire (double-ended/differential) IMSHO (that's "in my strongly-
held opinion"  8^)

My system is a ProJection that runs rich most of the time -- but, before
the hi-po roller cam -- I was able to get it to run okay near stoich
and the meter actually was useful in tuning.  Now, I tune for
power and it's always rich (wish I knew why ???).

Tom Cloud

 Clothes make the man ....  Naked people have little or no influence on society.