Odd readings from front 02 sensor on scan tool (1 Viewer)

[whitrzac]

The PO had a cobbled together exhaust, the front o2 was kinda in the pipe, but not really, and had multiple leaks.

Installed new magnaflow Y and 2nd cat. New Denso front o2 sensor.

Watching my scan tool the voltage reading bounces between 0.1v and 0.8/0.9v. The short term fuel trim is bouncing between -3% and -8%


Past experience from other cars tells me that it should be a stable voltage and not be bouncing all over the place.
Can anyone confirm that the 80s front o2 sensor reads properly with a scan tool?

1996 fzj80

 

[ppc]

Sounds normal to me.

 

[thabruiser]

Oxygen sensors fluctuate between lean (0.1v) and rich (0.9v) constantly. And the sum of the lean and rich should be stoichiometric. Think of it as being graphed, and the graph looks like a basic sine wave. Up, down, up down. The average of the "ups" and "downs" is (or the computer tries to make it equal to ) 0.5v. So I remember first putting an o2 sensor gauge on my old Eagle Talon, and it would sweep rich then lean constantly. It's not until you get the "wideband" sensors, or A/F sensors in later models that you have the consistent "stable" output.