Selectable Simulated Narrowband Signal Switching Point

APPLICATIONS

Now you can select the switching point of the Simulated Narrowband Output to force the ECU to maintain a richer or leaner mixture than 14.7 AFR (Lambda 1) in a closed loop. A stock narrowband O2 sensor switches at 14.7 AFR, forcing the ECU to maintain 14.7 AFR at closed loop. The ECU operates in a closed loop at idle and at low throttle (low engine load). The Zt-2 "knows" the entire AFR range and is capable of shifting the narrowband switching point to a richer or leaner region. The default NBSP is the same as a stock narrowband O2 sensor, 14.7. You can program the Zt-2 to output as desired by the ECU curve anywhere from 9.5 to 21.0 AFR. This could be used for better or for worse. Your engine was designed for 14.7 AFR at closed loop. Most engines will idle and drive at a lean closed loop AFR 15.5-16.0. This leads to a significant fuel savings! You can also force the ECU to idle on the rich AFR side to cover up big cam idle problems.

The diagram below illustrates the Narrowband Curve Switching Point being shifted from a stock 14.7 AFR into 13.4 AFR and 16.0 AFR. You can chose any AFR switching point between 9.6 AFR and 21.0 AFR. Most engines will not operate properly in closed loop leaner than 16.0 AFR. Most ECUs will not richen the mixture beyond 13 AFR at idle, ignoring the O2 sensor closed loop feedback.
 

A different than 14.7 AFR Narrowband Output will increase the smog output and may harm your engine and catalytic converter.
A different than 14.7 AFR Narrowband Output may trigger a Check Engine light.
Tune at your own risk and off road only.

SOFTWARE SETUP

Open the Zeitronix Logging Software. Connect the Zt-2 Wideband AFR Meter into a PC COM port and power up the Zt-2. Make sure the log graphs are shown on the screen. Open the Narrowband Switching Point menu by selecting Settings/Narrowband Switching Point

To Change the Narrowband Switching Point, adjust the number in the menu and click OK. The Narrowband Switching Point can be restored to a default value of 14.7 AFR by clicking on the Default Value, then OK.

COMPATIBILITY

All Zt-3s and Zt-2s rev 9 and above purchased after May 9 2006 are equipped with a Selectable Narrowband Switching Point feature.

You can check compatibility by accessing the Alarms window in the Zeitronix Logging Software Version 2.0.5 or higher.
Open the Zeitronix Logging Software. Connect the Zt-2 Wideband AFR Meter into a PC COM port and power up the Zt-2. Make sure the log graphs are shown on the screen. Select the narrowband setup or warnings setup options.  A message similar to the following will be displayed if an incompatible Zt-2 AFR Meter is detected. Contact sales@zeitronix.com for a possible Zt-2 upgrade.