Ram 5.7 Hemi Fuel Saver Technology

[Siegmann]

Last year (2014) when I was shopping for a Ram they touted their "iDFSO Technology" (interactive deceleration fuel shut-off). This year (2015) I bought one. Now they tout their fuel saving technology as the MDS (multi-displacement system) that shuts down 4 of the 8 cyclinders.

I'm still in my break-in period, so the transmission shifting is reportedly to be still a little rough, but when I take my foot off the gas to coast to a red light, I feel additional engine breaking kicking in. Could this be the iDFSO system shutting off the fuel? Nothing in Ram's info for the 2015 still lists this technology. Does anyone know if they took it out?

[idroba]

I have a 2012 Jeep Grand Cherokee which has the cylinder deactivation system. It has always been totally transparent, the only way I know it is on 4 cylinders is by the indicator light on the dash. No hesitation, nothin.

But I don't know anything about the IDFSO system.

I am a little unclear from your post which system you are asking about, or are they both on your 2015?

[slowmover]

The latest engines in some lines shut off the engine altogether at a stop. I'd imagine the trans is responding to the zero throttle input and braking/slowing of the truck. Engine compression braking is not really needed in this scenario.

[BoldAdventure]

My 2010 does both MDS and iDFSO, but only when driving it optimally. You get the little ECO icon. Tow/Haul mode will completely disable this.

[Siegmann]

Bold, I believe then that I too have both systems. Odd though that all the info available, including the owners manuals, never mentions iDFSO. But I sure can feel it kick in when I take my foot off the gas and begin to coast.

[BoldAdventure]

Put it in Tow/Haul mode and watch how much it changes. Car & Driver described it as the closet thing to a "Sport Mode" in a truck. Ford & Chevy's tow/haul mode doesn't even come close.

It is odd how there is no mention. We had the same experience of WTH is going on after we bought our truck, a quick search on ram forums answered that.

[Siegmann]

You're right, the Ram forum is a great source of info. The MDS fuel saver, that shuts down 4 cyclinders, is seamless. I really can't tell when it occurs. The iDFSO, that shuts off the fuel, is noticeable. Almost like the transmission is down-shifting, but it is not.

I do agree that the tow/haul mode, because of the electronic 8 spd, is amazing. It does things you couldn't possible do with manual shifting.