Quote Originally Posted by brian617 View Post
Some things to think about,

If you go back to the carbureted era you would remember that when you chop the throttle on decel the mixture is going to be very rich, high vacuum and closed throttle plates.

Leaning out the mixture or even cutting fuel completely, decel enleanment, causes high engine braking.

The moment you step back on the throttle the extra fuel in the manifold might help the transition without having the mess with AE too much.

With my 7427 and Manual transmission decel enleanment is very noticeable. I can feel and hear the change when the injectors quit pulsing.
Thanks - agreed that I do not want to swing things too far that would create a lean condition when I step back on the gas. But it will sit there and hang out at 10.9-11.1 or so continuously even on long decel events. Note that the conditions I am speaking of do not involve DFCO since they are outside of the parameters that allow it. DFCO is working fine from what I can tell. I'm mostly concerned about in-town driving where RPM is not high enough to allow DFCO. Also not talking about decel enleanment. AFAIK that is only triggered when TPS is decreasing, but still greater than zero?

I have been playing with those limits a little and I'm still pretty rich on decel, but it will lean out to the 12s or even 13s as the decel event continues. Seem to be on the right track. I'm at 425 minimum BPW now and will probably not go much lower than that. I have not noticed anything amiss when acceleration starts back up. One thing I discovered is to keep the two values the same (minimum value and minimum allowed value). I'm not sure why both are there, but when the allowed value was lower than the other one, things went a little wonky on decel with TPS greater than zero (foot still on the gas). In certain conditions I would get a surge with lean/rich swings. Keeping both scalars at the same value seems to resolve that.