Does MDS actually save fuel?

[Hemi395]

I decided to add all 8 Injector PW PIDs to my Trinity so I could see an approximation of fuel flow. injector PW measures how long the injector is opened for or "fires" for.

When the truck goes into MDS you can see the 4 cylinders shutting down which I was expecting. What I wasn't expecting was the 4 cylinders that are still active to essentially double the fuel output.

How does this save fuel if it just doubles the fuel into the 4 active cylinders?

MDS off

MDS on

 

[AFMoulton]

Wow! Thanks brother, not that MDS ever comes on in my 6.4! But this is interesting, it tells me the little thing on the dash is a liar too, when the Eco light comes on, your MPG bar goes through the roof. Doesn’t look to be true.


Sent from my iPhone using Tapatalk

 

[U&A]

my super unscientific opinion. If I drive for a full tank without using tow haul mode which will let MDS activate.... and then drive another full tank entirely in tow haul mode while MDS cannot activate and my RPMs are running higher my fuel mileage is basically identical.

MDS is garbage. Its a feel good the thing. All it does is make the MPG on the EVIC, and we lnow the evic is not correct with MPG.


JMO

I’m very interested to see what others have experienced or learned with the MDS system

 

[69GWC]

Yeap the MDS is just like 5w20 oil, its forced BS on the auto manufacturers by the government to try to get better fuel mileage out of these trucks.

Problem is this crap only works in a perfect world or in there lab and dont do **** in real world every day driving.


Thanks for posting that up.

 

[U&A]

Wow! Thanks brother, not that MDS ever comes on in my 6.4! But this is interesting, it tells me the little thing on the dash is a liar too, when the Eco light comes on, your MPG bar goes through the roof. Doesn’t look to be true.


Sent from my iPhone using Tapatalk

What year is yours? My 2016 ( built in sep of 15) the MDS is very active around town but not at all once i am going over 50 mph

 

[AFMoulton]

What year is yours? My 2016 ( buolt in sep of 15) the MDS is very active arpund town but not at all once i am going over 50 mph

18


Sent from my iPhone using Tapatalk

 

[Hemi395]

The Eco light is somewhat more accurate because when the mpg goes to 99 when you're coasting down a hill all 8 injectors go to 0 so essentially the pcm is cutting fuel completely from the engine. Found that out by using these PIDs.

But that has nothing to do with MDS. It cuts the fuel even when in manual shift or tow/haul mode...

 

[West27]

Wow that is some good data!! Such BS

 

[Jwithing]

The Eco light is somewhat more accurate because when the mpg goes to 99 when you're coasting down a hill all 8 injectors go to 0 so essentially the pcm is cutting fuel completely from the engine. Found that out by using these PIDs.

But that has nothing to do with MDS. It cuts the fuel even when in manual shift or tow/haul mode...

Wait... These things have an Eco light? Ive had the truck for a year and honestly didn't know that lol.

 

[BrianJE]

I have found the same thing in my 6.4L MDS does not help at all. All my calculations are done by hand not by the EVIC lie meter.

 

[Hemi395]

Wow that is some good data!! Such BS

I was surprised to see that. One would assume that when it cuts the fuel to the MDS cylinders the fuel flow other 4 stay about the same. I mean thats how to save fuel. But we all know what they say about assuming....

 

[Jwithing]

Sounds like a grounds for a class action lawsuits lol

 

[Burla]

Next time I go on a long trip I will test with a fill up before and a fill up after to be exact as I can. 55mph on cruise control as much as possibe, and I will do a t/h trip versus a mds trip, so everything would favor the mds trip as the rpm's will be higher in th, and I still wager at best it is equal.

MDS Japanese tech even if it isn't, huh? inside joke

 

[Hemi395]

Next time I go on a long trip I will test with a fill up before and a fill up after to be exact as I can. 55mph on cruise control as much as possibe, and I will do a t/h trip versus a mds trip, so everything would favor the mds trip as the rpm's will be higher in th, and I still wager at best it is equal.

MDS Japanese tech even if it isn't, huh? inside joke

Definitely interested in this. I tried to do this about a year ago but I could never get the tanks to be comparable. I'd have to do a lot of city driving for one and highway for the other. Plus the temp and humidity change almost daily here so thats a factor as well.

As soon as I pass the MA inspection in May I'm tuning MDS out again.

 

[69GWC]

Ha inspections whats that....

 

[Burla]

Frk'n Commies.

 

[Hemi395]

Yeah MA inspections are RIDICULOUS. Don't even get me started on this. The inspection stations have cameras for the inspector to take pictures of various things. Need I say more.

 

[69GWC]

Kansas has ZERO inspections...
and no permit to carry..lol

and I am going to use my old oil to start and burn my brush pile off and and dont need a permit...lol


Sorry back to MDS sucking...lol

 

[Burla]

Yeah MA inspections are RIDICULOUS. Don't even get me started on this.

In our defense, you started it

 

[Hemi395]

In our defense, you started it

Lol true