My current oxygen sensor is about shot and I'm getting ready to replace it. My firend suggested I get a heated one instead of a normal one wire sensor. I've looked into it nad I come up with only a few advantages; the ECM enters closed loop sooner, and better mileage in cold weather due to the closed loop.

Now, would a stock L03 benefit from any of that? Right now my car doesn't enter closed loop on the 15 min drive to school every morning. I still somehow manage to get 18 mpg in open loop. The o2 sensor just doesn't vary enough to kick the ECM into closed loop.

Call this starnge, but it enters closed loop on the way home. I'm guessing that sitting int he sun raises the underhood temperature a bit. Either that or I'm a bit heavier on the gas when I go home

 

You can install a 3- or 4-wire HO²S fairly easily:

 

Ok, thats a pretty cool diagram!

Is that set up so that the heater shuts off when the ECM enters closed loop? I'm not sure when the Evap relay is on and off. Or is that a separate relay? I was thinking of using the fuel pump relay, or possibly an AIR relay so that the heater shuts on and off. I'm not sure which is better. It probably doesn't matter for the life of the sensor or anything

 

The pink/black is hot when ignition is hot; the ECM usually grounds a circuit to activate it.