No problem. I started with the information here: (Thanks TomO)
http://www.gassavers.org/showthread.php?t=2427. I monitored the actual voltages for a while (a couple of weeks), and in my case, when the voltage exceeded about 3 volts (see post #20 for where I got that), I could tell I was in lean burn. You can feel it going into and coming out of it if you pay close attention. Then I took the information from here:
http://www.autospeed.com/cms/A_1716/...popularArticle and made up a circuit similar to that one. The differences are: 1) I added a 7809 voltage regulator to the supply voltage so that voltage fluctuations in the 12volts don't effect the set point (the author of that article addresses that issue at the very end - but I disagree with him, fluctuating supply voltage made a pretty big difference in the reference voltage) 2) I reversed the O2 signal and the reference voltage (pins 2 and 3) so that the led turns on as the voltage increases past the setpoint. The circuit autospeed has is designed so that the led lights when the voltage falls. I also chose a 330 ohm resistor rather than a 470 because I wanted the led brighter, but that probably doesn't matter much.
I've learned some interesting things from that light, for example I get better fuel economy in 4th gear if I can keep it in lean burn than in 5th without it. Significantly better in fact. The tendency is to get into 5th as fast as possible, but sometimes being in that tall a gear requires throttle positions that take you out of lean burn mode. And of course every situation is different. YMMV
BTW according to the gassavers garage, we have a
lot more than just 5 or 6 VXs here. Come on people, post.