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Thanks MechEngVT, as I discovered the exact same thing this weekend. My wife and I just drove out from SLC Utah to OKC Oklahoma over the weekend, towing her car. I had the truck loaded to 6500 pounds, just a little under max. I happened to see my truck activate a decel fuel cut-off when we were going downhill several times. I ran the SC 91 tune, had the tranny in tow/haul mode, typically with cruise on (but not always), and was going around 65 mph. I noticed the truck would downshift, fuel flow would drop to 1.15 to 1.35 gal/hr, and then if the hill or decel condition continued for a few more seconds, fuel flow would drop to 0.0. However, as the hill leveled off the cruise would pull the throttle cable and fuel flow immediately resumed...or if cruise was off, I'd press the gas and the truck responded in the same manner. This happened far more frequently in the Utah/Wyoming mountains than after we got into Colorado and Kansas...although I did get it to engage while coasting to a Tollroad booth yesterday in southern KS.
I agree, the DCFO does seem to drag its feet while engaging. I think it should be more agressive. This weekend's drive is the only time I have seen it engage routinely. I watched my MPGuino to see when it kicked in. I agree, the wire I cut did nothing. If I knew which sensor to trip to make it kick in sooner, that'd be great.
For whatever reason, my overhead console does not show inst mpg, only the tank average. Is there a way to change that?
I am actually trying to avoid an engine kill switch, as I'd still like to watch rpms (and I don't want to kill my auto trans). I figured if I killed the power to just the injectors, everything else would keep spinning... I have asked Superchips to look into and see if maybe they can work something into their tunes.
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