[Walt Fricke]

I just noticed that the better scope shows a ~36% duty cycle. Inverted, that would be close enough to 65%. Makes the scope work with less conversion than an analog dwell meter. It will record for a while, too - could use it if it proves useful for my racing purposes to hook up the stock O2 sensor.

Noting that the ECU has a separate pin for the O2 sensor input, I wonder if I could set up an oscillator or something, triggered by the WOT switch, which would cause the FV to operate at a 55% duty cycle in that range. A faux above 0.5V/below 0.5V signal at the right frequency. Would need to be PWM, not just frequency? Or just a frequency, since the equation is above a voltage, go one way, below it go another? With a variable frequency test input, what was needed for 55% could be determined by cut and try if not calculation from really understanding what is going on? Easier than trying to figure out where in that battleship of a PCB Bosch creates the default values, and how to alter something on the board to do that? I think it is all analog, with no tables of values or the like.