MicroSquirt.com read only forum (Jan.15,2018)

Have MsII v2.3abs firmware and v3 board with msd 6a

new discovery for me because i was attempting to tune with O2 at .45 v supposing this was stoichometric this educated guess is wrong for 107 and 108 Lobe separation angle cams.

turns out that i dissabled o2 correction and increased ve table until i reached a stable .8 v signal from the narrow band 02 sensor. engine now runs better at idle and cruise. clean white spark plugs.

so i can conclude that the intake charge contaminates exhaust charge then this fouls the O2 reading in such way that the end result is that .8v means around 15:1 so runing lean with an nbo2 means you are leaner than you think when tight Lobe center angles are used.

HOPE THIS TIPS HELPS EVERYONE WITH TIGHT LCA !!!

Alonso,

Voltages above 0.45 indicate rich mixtures with a narrow band sensor, voltage below 0.45 indicate lean.



http://www.megamanual.com/v22manual/mwire.htm#ego

I suspect you are probably around 13 to 13.5:1 at idle (which might give a sensor output of 0.8 Volts), that's where most engines similar to yours like to idle. The best method for tuning idle VE is to aim for miminum kPa, not a specific AFR.

Lance.