Synapsis

I just got my second Autometer A/F Ratio gauge installed today, connected to the NB output on the Zeitronix WB controller. When I originally received the Zeitronix I tried hooking up the NB output to the ECM to see how it'd work, and it didn't work very well. There was lots of stumbling and hesitation, so I reconnected my NBO2 to the ECM and it was driving fine.

Now that I have both gauges next to each other, I can see why. The Zeitronix box does simulate the edges of the NBO2 response by going full lean at 1.1 Lambda and full rich at 0.9 Lambda. It crosses past the 1 Lambda point *really* fast and really wide. When my NBO2 is only switching about 2 LEDs past 1 Lambda on each side around 4-5 switches per second, the Zeitronix was switching around 5 LEDs per side and so many switches per second I couldn't really see them. While driving, the NB might switch back and forth a little off center, say around 1.05 Lambda but the Zeitronix will be off in the full lean zone. I personally think the response of the Zeitronix simulated NB is too fast and sensitive to hook directly into the ECM on my application. The ECM would try to correct the lean condition, possibly overshoot, then it'd be off to correct the rich condition, back and forth. I'm sure it's possible to compensate for this in code (to a point), but I haven't researched how to do that just yet. Or maybe I just have a slow NBO2 sensor, but the sensor only has a couple thousand miles on it at the most.

The tests were done at idle and driving in closed loop. The BLMs were 128 +- 2 and the WBO2 was reading 128 +- 4 (128 being 1 Lambda.) For those of you using regular gasoline, 1 Lambda = 14.7:1 air/fuel ratio.

Just one person's experience, to add to the mass of info here.