Engine vibration at low rpm................

[00masterchief]

Low rpms at lower speeds can vibrate slight amount. When I'm driving 70km and other lower speeds if my rpms are below 1500 in MDS/ECO mode I think the 4 cylinders are struggling to maintain the speed at that low of rpm. My question is, is this normal or common and should I bring it in to be looked at under warranty. Like I said the vibration is so slight I'm not that concerned but it almost makes me want to either hit the gas to change speed so it stops or turn off MDS until I'm on the hwy cause at higher speeds the 4 cylinders usually are higher to maintain speeds against the wind resistance.
Has anyone experienced this and is it a normal operation of the engine and driveline, I'm not sure where its emanating but I assume the engine.
The White knight is mine

 

[Ken226]

It's normal.

If/when the day comes that I gotta do a cam and lifter replacement, I'll probably use a MMX no-tune cam and non MDS lifters.

Although, the "Truck Norris" cam does have a ring to it!

 

[RamInfo]

Hit the gear- button on the steering wheel to turn off MDS, then use the + or - buttons to set it to 8 and motor on smoothly.

Best,
RI

 

[Docwagon1776]

Low rpms at lower speeds can vibrate slight amount.

Running in 4 cylinder mode causes vibration as the forces aren't equalized left/right any longer since some counter strokes are basically bouncing on a trampoline of air vs being fired by combustion.

Some trucks it's more noticeable than others. 8 speed seems to make it more noticeable. Anything that stiffens the frame, like rock rails, will make it more noticeable.

There are counter-vibration devices installed on the frame which work kind of like noise cancelling headphones to provide counter-vibrations to diminish it. It's possible you have an issue, but it's likely just the normal shake.

*edit* My 2012 1500 with the 6 speed, you can't feel it at all. My 2021 PW with rock rails, I can feel it at lower speeds. At highway speed I can feel it through the gas pedal if I really concentrate, but otherwise it's invisible.

 

[JHoward]

... help me to understand.

What is ECO mode?

My 2017 RAM has never shown anywhere on the instrument cluster/gauges that some type of ECO mode is active or "on" ... or MDS for that matter, is active ...

 

[Ken226]

How to active “ECO” light in ram 1500 hemi

This will show you how to activate the ECO light on your dash which displays when the truck has kicked down into 4 cylinder mode.

youtu.be

 

[Docwagon1776]

... help me to understand.

What is ECO mode?

My 2017 RAM has never shown anywhere on the instrument cluster/gauges that some type of ECO mode is active or "on" ... or MDS for that matter, is active ...

Short version: it's the computer telling you that you are driving in a more fuel efficient manner than when it's not on. How it does that depends on the generation. 5th gen, it coincides with MDS. 4th gen, it does not. How it's displayed depends on which cluster you have.

 

[JHoward]

How to active “ECO” light in ram 1500 hemi

This will show you how to activate the ECO light on your dash which displays when the truck has kicked down into 4 cylinder mode.

youtu.be

I haven't any desire to activate "eco mode", thanks for the info.

 

[Ken226]

I haven't any desire to activate "eco mode", thanks for the info.

Unless you've done an MDS delete or disabled it with a tune, I think ECO mode is always there.

That setting just turns on the dash indicator.

 

[JHoward]

Unless you've done an MDS delete or disabled it with a tune, I think ECO mode is always there.

That setting just turns on the dash indicator.

My 2017 RAM 5.7 is bone stock.

Interesting, there never has been any indication anywhere on the "dash" or instrument cluster that my truck is in "eco mode" or MDS mode.

 

[Wild one]

Unless you've done an MDS delete or disabled it with a tune, I think ECO mode is always there.

That setting just turns on the dash indicator.

Even if you've done the mds delete with block off plugs,and completely removed the mds harness under the intake,a 4 th Gen will still show ECO mode if you have it turned on in the Evic.
Eco mode just tells you ,you're driving in an economical manner,has nothing to do with MDS.
My truck hasn't had the mds solenoids or the wire harness for them,for the last 9 years,and still turns on the Eco light

 

[Wild one]

My 2017 RAM 5.7 is bone stock.

Interesting, there never has been any indication anywhere on the "dash" or instrument cluster that my truck is in "eco mode" or MDS mode.

It's probably never had the light turned on J,it can be turned off or on via a setting in your radio

 

[JHoward]

... all of my 4th Gen RAM trucks,(2009,2011,two 2014's and 2017) RCSB Express lower packaged/options except for my 2009 which was, believe it or not, an Bighorn Edition RCSB with the 5 speed tranny and 3:55 gears/5.7 HEMI, did not show "ECO mode"/MDS mode on the dash or instrument cluster ...

It's why I asked ...

 

[Wild one]

... all of my 4th Gen RAM trucks,(2009,2011,two 2014's and 2017) RCSB Express lower packaged/options except for my 2009 which was, believe it or not, an Longhorn Edition RCSB with the 5 speed tranny and 3:55 gears/5.7 HEMI, did not show "ECO mode"/MDS mode on the dash or instrument cluster ...

It's why I asked ...

It has to be turned on in the radio. If the dealer never turned it on,good chance the owners didn't know about the eco light,and never turned it on either.They all have the eco light function,including the cars,except maybe the HD's,those i'm not sure about.

 

[Docwagon1776]

...,except maybe the HD's,those i'm not sure about.

2500 does, at least mine does.

 

[MyNewRam]

For the green eco light to show on the dash, scroll through your menu settings using the arrow buttons on the steering wheel. Under the menu is a page for fuel economy. If you pull that up, and leave it up, it’ll tell you whenever the motor goes into eco mode.

Side note, you can leave any one of those menu screens up on the display and they will stay up, regardless of turning on/off the truck. To go back to a. Blank screen, you have to go back into the menu and select the menu off.

Hope this helps.

 

[MyNewRam]

Also…. My ‘18 vibrates a little as well when it’s in eco mode. It also sounds odd…..like it’s really struggling and underpowered. I tested another and it does the same thing…so it’s doing what it should be doing.

 

[greywolf2112]

Running in 4 cylinder mode causes vibration as the forces aren't equalized left/right any longer since some counter strokes are basically bouncing on a trampoline of air vs being fired by combustion.

Some trucks it's more noticeable than others. 8 speed seems to make it more noticeable. Anything that stiffens the frame, like rock rails, will make it more noticeable.

There are counter-vibration devices installed on the frame which work kind of like noise cancelling headphones to provide counter-vibrations to diminish it. It's possible you have an issue, but it's likely just the normal shake.

*edit* My 2012 1500 with the 6 speed, you can't feel it at all. My 2021 PW with rock rails, I can feel it at lower speeds. At highway speed I can feel it through the gas pedal if I really concentrate, but otherwise it's invisible.

THANK YOU - this may explain what I'm feeling on my new-to-me 2020 1500. It is barely noticeable, and only occurs at 1200-1500 RPMs, and not all the time. Hopefully that's all it is.