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MDS Question

Has anyone experienced vibration when in eco mode (mds) between 30mph and 50mph
Cruising??
 
Mine does a little base (subwoofer) sound while on eco mode It vibrates and when I step on throttle and the 8 cilendera kick in it goes away please help!!
 
Welcome! First, it would be helpful if you included a description of your vehicle when you submit questions to the group, such as year, model, engine, transmission, 2WD/4WD, axle ratio, and any other pertinent information. Most put this info in their signature field so it comes up every time.

It's hard tell what you're feeling. I'm on my third Ram 1500 5.7 and all had MDS and all three exhibit a very, very small degree of "vibration" when the engine is in the 4 cylinder mode (MDS) and under a slight load. What I'm describing was not something noticeably felt in the steering wheel, the gas pedal, or the body so much, but more of a sense since you could hear the switch to 4 cylinder when this occurred. It was similar to lugging down an engine in top gear at low RPM and at low speed.

My apologies as this response is not very descriptive. In any case this 'vibration' was nothing like a fouled spark plug.

Sorry if this was not very helpful.

Best regards,
Dusty

2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33 gallon fuel tank, factory dual exhaust, 18” wheels. Now at: 008052 miles.
 
Guys just bought my first new truck ever. It is a 2019 Ram 1500 Lone Star Crew Cab 4x4 in Rugged Brown Pearl. Thanks for all the info. I'm trying to learn about all the new Tech and this form is helping alot.

Thanks

2019 Ram 1500 (Rugged Brown Pearl) Lone Star Crew Cab 4x4, 5.7 Hemi/without etorque, 3.21 axle, factory exhaust, 20" wheels. 1450 miles.
 
Hutch70 said:
I don't know if this has been discussed before but, It Appears the MDS in my RAM doesn't engage like it should. while traveling at a constant speed it rarely engages, but when I take my foot off the gas or disengage CC the ECO tight comes on. I had a 2014 Charger R/T and it always kicked in when it was supposed to. I have the 3.92 rear end, don't know if that makes a difference.
Click to expand...
My 2012 ram 1500 did this and got horrible mpg so on a cross country trip I took along a half filled gas tank for backup drew the tank down to about 5 gallons and put 4 bottles of seafoam in it. Now with no head wind or verticle climbs, when it is on under 70mph it runs solid. I cruised from NM to NC with it and averaged 20mpg in speed ranges between 65 and 75 after treatment. Before that I was getting 13 to 19 highway depending on the conditions. Running a windows driven OBD I read there were some cylinder misfires. I'm not smart enough to know what this means and if it was related. But you might want to check for that.
 
My truck is also a 3.92 rear ... And my Eco light is on most of the time it seems. Since it's based on load, I'd think the 3.92 is beneficial since it takes less engine power to maintain a static speed, all other things being equal.
 
The transmission could play a role in that scenario. A 3.21 could be in another gear if they were directly compared. Would be interesting to see any differences in gear selection between the different rear ratios under the same loads.
 
I will back tdwill up here, I have managed auto dealerships for the last 20 years, most of the reps no less them many of my sales people. They are usually just a suit that doesn’t have any answers unless they contact somebody else, or they heard it from another sales person and pass on bad info. It goes back to when someone tells a story and it keeps getting passed on and the story changes completely. I’ve seen it 100 times. So I wouldn’t be able to tell you was wrong or right here but never rely on much info unless it is in print from the manufacturer.
 
So Im new to trucks in general. I keep seeing this MDS and ECO in the forums but haven't seen any light come on. I watched a few videos on how to enable the light via the settings but mine doesn't show that option. Do all Rams come with MDS?
I have a 2019 5th gen Ram bighorn Hemi with tow package.
 
Midnight1 said:
So Im new to trucks in general. I keep seeing this MDS and ECO in the forums but haven't seen any light come on. I watched a few videos on how to enable the light via the settings but mine doesn't show that option. Do all Rams come with MDS?
I have a 2019 5th gen Ram bighorn Hemi with tow package.
Click to expand...
ECO light is turned off by default. You need to enable it from within Uconnect in settings.
 
Midnight1 said:
So Im new to trucks in general. I keep seeing this MDS and ECO in the forums but haven't seen any light come on. I watched a few videos on how to enable the light via the settings but mine doesn't show that option. Do all Rams come with MDS?
I have a 2019 5th gen Ram bighorn Hemi with tow package.
Click to expand...

When you get a chance fill out your signature with your options etc. Makes it easier. Given you said you have a Hemi you have MDS (multi displacement system) which will shut down 4 of the 8 cylinders when they are needed. You can enable the “eco” light in the Uconnect settings so that you can see it illuminate in your instrument cluster when it engages.
 
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I saw on one of these replies that someone didn't notice the MDS kick in until they had around 400 miles. I get my Eco light on a good amount but I have never noticed a difference in sound or feel to indicate that MDS has kicked in and until I just looked back over my window sticker a few minutes ago, didn't even know I had MDS on the engine. I have had the truck since the 7th of this month so around 3 weeks now and only have around 370 miles on it. Most driving is back country roads doing 45-60 MPH here in NC and only had it on the highway once. You would think Mopar would put in a light or something to tell you that you were only running on 4 cylinders. I know Chevy does that in their truck with a light that comes on that says V-4 or something like that. So does it not kick on until the engine has "broken in" with a specific number of miles driven?

I know from other reading that the Eco light is just a light saying "hey you are driving efficiently" and doesn't nesecarilly correlate with MDS being active.
 
JordanS_2020RamBTSEdition said:
I saw on one of these replies that someone didn't notice the MDS kick in until they had around 400 miles. I get my Eco light on a good amount but I have never noticed a difference in sound or feel to indicate that MDS has kicked in and until I just looked back over my window sticker a few minutes ago, didn't even know I had MDS on the engine. I have had the truck since the 7th of this month so around 3 weeks now and only have around 370 miles on it. Most driving is back country roads doing 45-60 MPH here in NC and only had it on the highway once. You would think Mopar would put in a light or something to tell you that you were only running on 4 cylinders. I know Chevy does that in their truck with a light that comes on that says V-4 or something like that. So does it not kick on until the engine has "broken in" with a specific number of miles driven?

I know from other reading that the Eco light is just a light saying "hey you are driving efficiently" and doesn't nesecarilly correlate with MDS being active.
Click to expand...
You've been misinformed. When the ECO lamp is illuminated it does indicate that you are in the 4 cylinder mode.

On all three of my Ram 1500 with MDS there was a short period when new that the MDS would not activate. I believe by the time they got 200 miles on the engine the MDS began to activate regularly.

Best regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33 gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 03 June 2018. Now at: 038577 miles.
 
My first truck was an early build 2019 big horn. While it was level 2, it didn’t have Uconnect and there was no way to disable the light. My 2020 has it and the light was disabled by default. Once I enabled the light, it started illuminating in the correct conditions. But it did NOT engage MDS. I searched the forum and this was the first reference I found that it’s disabled for the first 400 miles - which makes total sense from an engine break-in standpoint. And since I’m still under 200 miles, that explains why I haven’t heard it yet. Assuming you have mostly regular hearing, and turn down the radio, you WILL hear it when it goes into mds. Mainly because it sounds like sh*t. Pretty much like you’d expect a v4 (not made by Lancia) to sound like. Which is why I think a lot of guys disable it, especially if you’ve done aftermarket exhaust...
 
210 miles in the clock, truck went into mds for the first time. So ~ 200 miles is key. A little harder to hear over the off road tires (wildpeak a/t) but definitely there.
 
Hutch70 said:
I don't know if this has been discussed before but, It Appears the MDS in my RAM doesn't engage like it should. while traveling at a constant speed it rarely engages, but when I take my foot off the gas or disengage CC the ECO tight comes on. I had a 2014 Charger R/T and it always kicked in when it was supposed to. I have the 3.92 rear end, don't know if that makes a difference.
Click to expand...

Mine never kicks in above 45-50 mph.. and even then it's rarely. I need dead level ground or downhill and it'll kick in for maybe 30 seconds to a minute, then kicks back out.. almost feels like a misfire. I've played around trying to keep it engaged.. but rarely can maintain speed for any length of time with it engaged.
 
Neurobit said:
No. There is not light for MDS.
Eco light will turn on (if enabled in UConnect first) if you are driving efficiently, regardless of MDS being active or not.
Click to expand...

Have to disagree with this. The Eco light always comes on/off with MDS in my truck. You can hear / feel the MDS kick on/off and it always corresponds with the ECO light.
 
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