[GTyankee]

You should not feel your engine going into or out of Cylinder Deactivation/Activization
Sometimes you may hear a change in tone coming out of the exhaust

Many people go by the ECO Light, but that is only an indicator that tells you that you are driving in the most efficient manner possible while the engine is functioning in Multi-Displacement System mode (MDS)

Your engine can be in MDS, without the ECO Light coming on
but
The ECO Light can't turn on, unless the engine is in MDS mode

On earlier Engines that had the MDS system which began in 2006 on the Ram with the HEMI engine.
The ECO light was indicated with the words FUEL SAVER

 

[farmadillo]

Thanks for the response. I guess I need to have the MDS looked at then. I previously had a 2002 Dodge Ram SLT 4.7L and it did not have the MDS or wasn't available back then.

 

[rcairflr]

Your engine can be in MDS, without the ECO Light coming on
but
The ECO Light can't turn on, unless the engine is in MDS mode


[/U]

Huh? Are you sure about this?

 

[Ramzaq]

Couple of things here, make sure you are running the proper weight oil for the Hemi, 5W - 20W. Another thing to be concerned about is the trans and the TC not disengaging properly from overdrive. When was the last trans oil change? Sometimes the computer is slow to react when it is monitoring all the input signals.

MDS works in milliseconds, faster than the blink of an eye. I think it is in the 400 ms range so you should never feel it

 

[GTyankee]

You will feel it in conjunction with other things
If you are using Cruise Control & beginning to go up an incline
The MDS will go into 8 cylinder mode, the Speed Sensor will notice a drop in speed, usually 3 to 5 mph drop, it signals the main computer, it tells the RPM to speed up to hold the Set Speed & at the same time the transmission shifts out of Drive to the next lower gear

Now if your driving on flat ground using Cruise Control & your ECO light is on
You can push the + one time & gain 2 mph, then hit it again & gain 2 more, but if you do it too quickly, it will go into 8 cylinder mode & your ECO light will go out

rcairflr, i am almost 100% positive about

Your engine can be in MDS, without the ECO Light coming on
but
The ECO Light can't turn on, unless the engine is in MDS mode

I believe that if you were to go to the Engineering Chat that was posted a few years back on this RamforumZ, you could read it for yourself

A former member on the Z was a very good Tech, he used the screen name of Ramtech
& he explained it in laymans terms.
Unfortunately he left because some people insisted on calling dodge dealerships by the name of stealerships & he took offense because he took pride in his job


i believe this is the chat

http://www.ramforumz.com/RamZoneChat.html

 

[farmadillo]

Thanks

Thanks GT Yankee for your help on this. I will look at the thread you posted.

 

[farmadillo]

Thanks Ramzak

Thanks for the reply Ramzak. I bought the truck used a couple of months ago with 120,000 miles. I have changed the oil with 5W-20 Mobil 1. I have not changed the transmission fluid. I will do that and have the MDS looked at. Thanks everyone for all your help!! :smileup::smileup::smileup:

 

[rcairflr]

GT Yankee, I am pretty sure you have it completely backwards. The ECO light can be on without being in MDS mode indicating you are driving economically, but the ECO light will be on if in MDS mode.
Maybe someone else will chime in on this.

 

[Thunderhorse]

GT Yankee, I am pretty sure you have it completely backwards. The ECO light can be on without being in MDS mode indicating you are driving economically, but the ECO light will be on if in MDS mode.
Maybe someone else will chime in on this.

This is correct, the ECO light can be on even with MDS disabled in ERS mode.

The 4.7 never had MDS, it was a SOHC engine. One big reason it got canned after 2013 is it made less power than the Hemi because it was smaller, but also got worse fuel mileage.

 

[Ramzaq]

Using ERS will turn off MDS.

Tow Haul will not turn off MDS

In normal operating "ECO Mode" or "Fuel Saver" for early 2009s, MDS will not be on unless you are in the two former modes.

If you turn off the dash display, the above two mentioned modes, the truck will still enter MDS under the right conditions

 

[bones007]

According to the owners manual the ECO light is the indication that the MDS is engaged... but others say not so , why can't Dodge be like GM where it actually shows how many cylinders are in operation right on the dash at any given moment?....would be less confusing....

 

[SouthernBornRebel]

GT Yankee, I am pretty sure you have it completely backwards. The ECO light can be on without being in MDS mode indicating you are driving economically, but the ECO light will be on if in MDS mode.
Maybe someone else will chime in on this.

Agreed.... ECO seems to be merely with gas pedal positioning, therefore is more electronic pedal sensor rather than accurate readings, same with the "prediction" of how many miles left with tankful of gas and the electronic "gas mileage" you are getting, neither are correct, manual mathematics is the only way to tell actual gas mileage
I run a Pedal Commander and ECO comes on all the time when off pedal or lightly on it, goes off under more stern acceleration positions....

 

[14vern]

This was last posted to 5 yrs ago.