Commanding leaner AFRs
Posted: February 7th, 2019, 8:19 am
I'm trying to command leaner AFRs on my 3MPS BK (mazdaspeed3 gen1) but whatever I do it goes back to stoich. I hoped that commanding just slightly leaner (just for cleaner burns, nothing major) below 1.03 lambda (1.01-1.02) will trick the ECU into accepting it, but it actually doesn't.
I instructed a few friends to disconnect the secondary O2 and I successfully tuned their cars with leaner AFRs in closed loop which improved closed loop fuel economy quite a lot and resulted in cleaner burns. But this doesn't work with the cars that have the secondary O2 still plugged in.
Are there any tables that need to be exposed or it there any of the existing tables that can be tweaked to achieve this without disconnecting the secondary O2?
I guess another approach would be to disable fuel trims above a certain load point set very low (0.25) and trick the ECU using the MAF calibration, but closed loop fuel trims are really helpful so I would not go this route.
I instructed a few friends to disconnect the secondary O2 and I successfully tuned their cars with leaner AFRs in closed loop which improved closed loop fuel economy quite a lot and resulted in cleaner burns. But this doesn't work with the cars that have the secondary O2 still plugged in.
Are there any tables that need to be exposed or it there any of the existing tables that can be tweaked to achieve this without disconnecting the secondary O2?
I guess another approach would be to disable fuel trims above a certain load point set very low (0.25) and trick the ECU using the MAF calibration, but closed loop fuel trims are really helpful so I would not go this route.