Where to connect multimeter to O2 sensor on 300E?
 

My '86 w124 300E is currently using an obscene amount of gas. (~10 mpg)
So i want to try adjusting the mixture by measuring via the O2 sensor, but i'm having som troubles.

First.. In some threads it is advised to measure the O2 sensors duty cycle. Others advise to measure voltage from the sensor. Which is most correct?

Second.. I can't, for the love of life, figure out where to connect the multimeter to the signal wire from the O2 sensor. -There's no way i can tap into the 6 mm length of visible wire coming from the sensor and disapearing into the buttom of the vehichle. Where does this wire end? And can i tap it from there? Or do i have to gut the cabin to get under the carpet?

Any help willl be appreciated.

Freestyler

Not sure about the 124's, but on the 126's the O2 sensor makes the connections under the passenger side false wall in the footwell. Pull up the pass side carpet then remove the false wall. Connection is likely at the lower left side of the floor.

In the past there had been multiple discussions on drastic reduction in fuel mileage with no other problems noted. Replacing the O2 sensor restored fuel mileage to norm.

Look up my thread called "My last OVP/EHA question, I promise". Mr Broterton finally got it through my thick skull about how to check these items. My problem is a leaking fuel distributor so the test results really didn't mean much for me.

Thanks guys.

That actually cleared up a lot of things.
Now i'll just have to wait for the weekend to it out.

Freestyler