Wideband O2 observations (i.e. Toyota AFR)

[Eddie_in_Maine]

Cruising at 70mph (ideal lambda, 14.7:1)
O2 B1S1 = 3.235V
O2 B1S1 = 0.025mA
O2 B1S2 = 0.445V

Coasting at 70mph (ideal lean condition)
O2 B1S1 = 4.995V
O2 B1S1 = 2.600mA
O2 B1S2 = 0.075V

The wideband O2 is B1S1 obviously and has roughly a 2.5V to 5V output variation with 5V being the leanest. An important observation is that for full lean, the sensor puts out a considerable amount of current, 2.6mA. This appears to be the delima, I need an EFIE enhancer than can produce >3.2V and act as a variable current source from 1mA to 2.6mA.

Vehicle = 2008 Camry, 2.4L 4cyl, (A)

My scanner is a POS and I need to get a oscope to look at the actual wideband signals, but the autotap.com software appears to be able to graph. May go that route. Just sharing my Toyota observations....

Intersting that Toyota puts a narrow band after the CAT, which I believe is to save cost and meet regulations.

[pj91gsx]

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Intersting that Toyota puts a narrow band after the CAT, which I believe is to save cost and meet regulations.

Many cars have an o2 after the cat. The reason for the o2 after the cat is to make sure the cat is working properly. It is not necessary otherwise. all it does is throw a cel when the cat goes bad. :cool:

[Eddie_in_Maine]

Yep, exactly. It was just interesting that Toyota threw in a cheap narrow band O2 instead of a mack daddy wide band O2 downstream. Obvious that is really doesn't need to be that accurate like you mentioned and is just to throw a code. My downstream does go to very rich while idling, showing that the CAT doesn't do a darn thing unless it is hot.