Besides mpg is there any major drawbacks to run open loop earlier ? Are there any redflags to getting into open loop sooner ?
I'm not SS, but here is what I learned. As long as your fuel table can make smooth transition (from 14.7:1 to your open-loop target AFR), everything will be good. When I'm 5th gear cruising on hwy, it runs in closed-loop. Whenever I apply partial throttle to speed up, it switches to open-loop (but still around 14.7:1 to 14:1) and waits for WOT. BTW, all the EM helps out to exit the close-loop sooner.