Eco mode while at idle

[Fireman48]

My truck goes into eco mode as normally expected. When slowing down for a red light it comes on but while at idle waiting on a green light to go the green eco light goes off. Am I running on 4 cylinders then or am I idling on all 8?

 

[JoeCo]

My truck goes into eco mode as normally expected. When slowing down for a red light it comes on but while at idle waiting on a green light to go the green eco light goes off. Am I running on 4 cylinders then or am I idling on all 8?

The eco light coming on does not necessarily indicate MDS being active (going down to 4), it just indicates that you are driving in an economical fashion. Just going to guess that at ideal the truck wouldn't be in 4, could definitely be while slowing down though. Easiest way to tell when MDS activates is by swapping out to the a louder muffler, then you won't be able to miss it when it happens, and then you'd probably do what most of us do and just deactivate MDS altogether.

I can't really remember how noticeable it was with a stock muffler, but it's completely obvious with an aftermarket muffler.

 

[PowerWagon18]

Wait, you can disable MDS? How is that done?

 

[JoeCo]

Wait, you can disable MDS? How is that done?

You can turn it off permanently with a tuner, or each time you drive it by either going into tow/haul mode or going into manual gear select mode (and just put it in the highest gear, trans will act as normal but no MDS). I've done it both ways with the 3 rams I've had, my current 17 I don't have tuned and don't plan too so I just go into manual mode and gear 7 or 8 depending on what speeds I'll be going. Not a hard habit to get into, doesn't bother me to do it at all. The tuner for newer trucks like ours is pricey, with having to buy a new PCM etc... which is why I won't be doing it on my current truck. On my 11 and 13 that didn't need that, my tuner was great for turning MDS off and it's other benefits, all at a reasonable cost, unlike newer trucks.

 

[Fireman48]

The eco light coming on does not necessarily indicate MDS being active (going down to 4), it just indicates that you are driving in an economical fashion. Just going to guess that at ideal the truck wouldn't be in 4, could definitely be while slowing down though. Easiest way to tell when MDS activates is by swapping out to the a louder muffler, then you won't be able to miss it when it happens, and then you'd probably do what most of us do and just deactivate MDS altogether.

I can't really remember how noticeable it was with a stock muffler, but it's completely obvious with an aftermarket muffler.

I have the Carwen exhaust which is plenty loud, louder than most w 5" tips and I dont notice any change in the exhaust tone whatsoever.

 

[JoeCo]

I have the Carwen exhaust which is plenty loud, louder than most w 5" tips and I dont notice any change in the exhaust tone whatsoever.

Perhaps Carven has perfected it then, I couldn't say as I've never been in a Ram with that setup. My setups were blatantly obvious not only in sound but feel, especially coming out of MDS back into 8 cylinders...that's why a lot of people with aftermarket setup disable the MDS one way or another. That's my primary reason for doing it as well, I'm also not so sure I care for it aside from that anyways. My rams have gotten the best gas mileage I've ever gotten in the 10 cars I've owned in my life, and mostly not using the MDS, so I'm happy to run it in 8 all the time.