On my 2001 Silverado 1500HD with 6.0L gas engine, I just rebuilt the heads and installed a mild aftermarket cam for good measure. Anyway, while redialing in the tune, I took my family on vacation (in the truck) and left DFCO disabled for roughly 3000 miles. During that time the truck barely used 1/8 of a quart of oil, which is great for one with 273k miles. Anyway, I got home, dialed in the tune and enabled DFCO to find that oil consumption picked up, so I'm thinking the extra vacuum under DFCO is sucking oil in the PCV value.
I was poking around in HPT and under idle->airflow there are a few parameters related to "DFCO airflow". "Idle DFCO Entry hold time" says time delay before entering DFCO airflow. Is there a DFCO airflow table that we can't see? Does the PCM target that table under DFCO? Anyone played with "Idle DFCO Entry hold time"? I'm curious if I crank that value up if the truck will still go into DFCO, but maybe not close the IAC or whatever it's doing.
I plan to do a bunch of logging this week, but would love to learn if someone has already played. Thanks again.