O2 sensor's

[Scott Shotton]

Ron Tyler wrote:
> 
> Hey All,
> 
>         This is probably a stupid question but, here goes... From what I
> know, an A/F ratio of 14.7:1 is chemically correct, meaning that there
> should not be any fuel nor any oxygen left. If I am correct, How can an
> o2 sensor read anything beyond a true 14.7 if there is no longer any
> oxygen?
> 
> --
> Ron & Stephanie Tyler
> '72 LT1/T56 240Z
> WOT untill you see God... then BRAKE!


14.7 to 1 doesn't mean 0% oxygen.  You still have o2 in the exhaust.  An
o2 sensor is like a battery.  It compares oxygen content of the
atmosphere to ox content in the exhaust and generates a voltage.  450mV
is 14.7 to 1.  Anything higher is rich and anything lower is lean.  The
computer will vary injector pulse width up and down to cause the scoped
O2 signal to look like a sine wave.  Basically averaging out to a 14.7
to 1 ratio.

There are a lot of variables that go into emissions.  But, I think I
have probably answerd your question.  If you need to know more, let me
know.

Scott