I've noticed when running VCM scanner that fuel cutoff never seems to happen when in 4th gear. It does go into 4 cyl mode though but fuel always stays on even though rpm parameters and such are met. Now if i go into 3rd gear then fuel cuts off like clockwork as expected. 4 CYL mode does not work in 3rd gear though. Does 4CYL mode prevent DFCO from occuring?
Correct, if you look at the DoD Disable vs. PRNDL in your tune, you will see that only in D4 should DoD be active. Therefore, if you force 3rd gear on the shifter, no Dod.
I struggled with trying to get DFCO to work and from what I understand, the reason for it not working in D4(Even with DoD turned off), is that DFCO will not be active when the truck is in overdrive(D4).
I have yet to figure out or found someone that can figure out how to get DFCO to actually work on these trucks.
Edit: Shrek mentions here that is has to do with the torque converter locking: http://www.hptuners.com/forum/forumdisplay.php?f=50
Last edited by Gh0st; 07-19-2012 at 08:24 PM.
2012 Chevy Cruze A6 1LT RS
Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado
Lol.. interesting. I've noticed that if i lower it into 3rd, that DFCO will activate if im rolling or going downgrade. I can then move it into 4th and it will stay in DFCO enabled, but it will stay in 8 CYL mode.
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