<mmdir2005@yahoo.com> wrote in message
news:1141377961.625238.241100@i40g2000cwc.googlegr oups.com...
>
> I've read a mechanic book. It says on Oxygen Sensor page that
> do not solder Oxygen sensor wire because it might cause
> misleading the voltage. I'm kind of doubt if soldered wire
> would make different voltage reading from unsoldered wire.
> How can a soldered wire and unsoldered wire make different
> voltage reading? Does anyone ever heard of this or know this is true or
> false?
>
Yes, this is called the galvanic effect and is the basis of how
thermocouples are made. Dissimilar metals have a contact potential that
varies with temperature. If the solder is between the two wires, any small
temperature difference will create a voltage across the joint, hence giving
a bad reading. You got good advice.

Dave