rear o2 sensor/fuel eficiency

adrian22 · Post by **adrian22** » 22 Oct 2005, 09:11

I have a question:do i need to change both o2 sensors if the front one was changed?I have a850 nonturbo 96-the AMF is new...
My mechanic told me that only front one is responsible for mixture and do not need to change rear one.I had code for rear one only but replacing front o2 solved the rich mixure problem.I read that the two sensors are working together to adjust mixture and if the rear one is bad and front one will be somehow affected too.Is this true? I try to get a better than 20/city-29/hgy mileage...
Also what is the chance to clean my self the o2 sensors? if carbon deposits are responsible for sensor failure-it can be clear easy?

Post by **matthew1** » 22 Oct 2005, 13:36

I don't know the answer to the front-rear question, but as to cleaning, I've read more than once that it's possible with a propane torch. Here's a Google search for "sensor+torch" limited to this website. Browse through those to find out more:

http://www.google.com/search?q=sensor+t ... vosite.com

White850Turbo · Post by **White850Turbo** » 22 Oct 2005, 19:13

The rear o2 sensor plays no part in A/F mixture on the Motronic ECU cars. It is just there to verify proper function of the catalytic converter. If you keep getting the CEL for it, you can try cleaning it off as Matthew suggested above or if that doesn't work, you can install a rear o2 sensor simulator instead of paying the absurd price for a new o2 sensor.