Hi Andrew,
For the wideband O2 sensor mod:
I bought a
PLX M250 Controller like this one. It comes with a narrowband analog output. I didn’t use it because it fixed at 1:14.7 ratio. What I use is the wideband output (0-5V). However, the wideband output is the invert of the narrowband. Also, the wideband is a linear signal and narrowband is more like switching signal. To make the wideband signal looks like narrowband signal, I use a
Schmitt Trigger to convert it. By changing the R1 and R2 values in the Schmitt Trigger, I can change the trigger voltage which in turn change the mixture ratio.