MDS Questions

[Grizeg]

Is MDS actually bad? I hear about the wiped cam lobes, in fact a friend of a friend has a Ram with a wiped lobe at 112k miles... HOWEVER he says it's cylinder 3... I thought it was Cylinders 1, 4, 6, 7 that were affected by MDS... I however had not actually looked at the cam myself... but that's what his mech tells him...

I unplugged mine at 1600 miles on my 2018 1500
I'm now at 8300 and enjoy the way the car responds without it.
However I am tired of looking at the CEL, and now I will not know if I throw a code for something else...
I plan on doing a cam in February around tax time... with that comes the delete kit, and a tuner.

I guess my Questions are as follows...

Is it actually bad?
Has anyone gotten more than 150k with or without it?
Has anyone else unplugged it on a new truck while the truck was at low miles and how long has it been unplugged and were they any negative effects?
Will it actually save a factory cam and lifters being disconnected....
And is it 1,4,6,7 that is affected...

Thanks.

 

[Grizeg]

Does no one have any answers, or has this **** been asked to many times... what gives.

 

[huntergreen]

Some Rams have a lifter and roller fail which wipes out a cam lobe. Many don't. It is not related to MDS. If you take a look a look at the synthetic oil thread, you find many believe the issue is caused by by the recomended 5/20 oil and run a 5/30 oil. Specifically red line 5/30. The reasons for this is posted in the syn oil thread.

 

[Fitz-0518]

This forum has a ton of threads on MDS. I have followed the thoughts and opinions. It seems there are two thoughts or groups. One, hates the feature as they claim they can hear the difference in their exhaust system and feel it when it activates. Those with the 8 speed trans tend to be more sensitive to the activation. Others do not notice it after their trans goes through the learning curve. In my 2018 6.4 6 speed, I could feel the MDS activate and cancel during the first 1000 miles. Since the trans has taken a set, we don't notice it "as much"
There are those who always deactivate MDS when they take off. Believe that having 4 cylinders fire while dragging the other 4 along cannot be good for an engine, long term. The mileage benefit of MDS is not significant. I have not read any where that MDS is thought to be a contributor to the valve train issue that some 5.7 and 6.4 Hemi's have.

 

[UnsatFC]

How did you unplug it?

 

[Fitz-0518]

How did you unplug it?

Didn't. We just use the gear shift setting at 6 to keep it out of MDS.

 

[UnsatFC]

Ah ok, thought you knew something I didn’t but that’s what I do too.

 

[Grizeg]

How did you unplug it?

If you take the plastic cowling off the top of the engine, on top of the engine, driver side close to firewall, there's a 4-5 pin plug, that i unplugged on mine, it throws a CEL but it never activates it again... I say 4-5 because mine was a 5 but its an 18 and everything i read online about it says it was a 4 pin... I'm guessing they added something new to that connector on my year, and if i had to guess i would say its the cam sensor as i get a light for that too... however the truck runs and drives fine, i assume the timing it off the crank sensor when the cam sensor is unplugged, i don't like have the CEL but I was tired of shifting it every time i took it out of gear or got into the truck... sooner or later i will order the tuner for the delete and later a new cam, lifter and delete kit.

cheers

thanks for the responses.

 

[huntergreen]

Didn't. We just use the gear shift setting at 6 to keep it out of MDS.

I thought tow/haul mode also deactivated MDS. Is this not true ?

 

[Fitz-0518]

I thought tow/haul mode also deactivated MDS. Is this not true ?

I can't say that I have gotten a clear answer to that question. Some postings say yes other no. When towing we are now engaging tow/haul and setting trans select at 6.

 

[huntergreen]

I can't say that I have gotten a clear answer to that question. Some postings say yes other no. When towing we are now engaging tow/haul and setting trans select at 6.

Thanks Fitz.

 

[Longhorn1500]

^^ I know on my '14 1500, the cylinder deactivation still operates in tow/haul, unless (as stated earlier) the transmission is in gear-limiting mode. This surprised me since I thought the system would understand that when in tow/haul, you would not be able to maintain the "eco" mode (due to load) much and it would be turning on and off a lot.

 

[Ramnewbie]

I thought tow/haul mode also deactivated MDS. Is this not true ?

From what I've read and my experience it depends on what year and what transmission. Some with the 6 speed say yes T/H disables MDS. My 17 with 8 speed T/H changes shift points and MDS doesn't activate as much but still does activate. The only way for me to completely shut it off is with the shift buttons.

Sent from my XT1650 using Tapatalk

 

[jws123]

My cam went bad so i 100% removed mds with non mds lifters and cam also tuned it out and i don't miss it 1 bit would never go back. It was just a ****** idea to get people to buy the truck thinking it would save them money and gas when in reality it doesn't.

 

[Fitz-0518]

Thanks Fitz.

I went back and checked some of the archive post on this. Hunter it looks like this feature and how it functions depends on the year. I am reasonably sure that in our 2018 CC 2500 66RFE 6.4, MDS is fully off with tow on and gear select set at 6. Now I do not think doing this will cause any trans issues or the engineers would not have allowed us to be able to do this. But, that is just my logic.

 

[pacofortacos]

For most with the 8 speed trans, tow/haul does NOT disable MDS.
But using ERS does, once dropped out of D and into any of the 8 speeds via the steering wheel buttons disables MDS.

 

[ram1500rsm]

I have mine tuned out in the calibration, there are no I'll effects for not having it enable and your exhaust sounds like it should if you have aftermarket mufflers. Transmission doesn't care about mds either.

I have a 10 Silverado that my wife drives, and I did disable the DOD (MDS) when I bought it used with 28k miles, that truck has now 102k miles, and has never seen 4 cyl ever again since then.
I had an 09 Pontiac G8GT that came with DOD as well, feature disabled the moment I drove it out of the dealer with 6 miles on it, sold the car years later with 160k miles and had zero issues.

 

[grizzstang]

I am not sure why you would unplug the MDS on a new truck and stare at a CEL when you can turn it off with the shift buttons. If you ever went in for warranty work I would love to hear what the dealer has to say about unplugging the MDS.

Put it in D hit the - shift button on the steering wheel (you should see a 1) then hit the + button up to 8. Done. It is a bit of a hassle to do this every time you put it in drive but it won't mess with your warranty.

 

[jws123]

I am not sure why you would unplug the MDS on a new truck and stare at a CEL when you can turn it off with the shift buttons. If you ever went in for warranty work I would love to hear what the dealer has to say about unplugging the MDS.

Put it in D hit the - shift button on the steering wheel (you should see a 1) then hit the + button up to 8. Done. It is a bit of a hassle to do this every time you put it in drive but it won't mess with your warranty.

Or you can buy a tuner for bout $200 turn mds off and uninstall it every time you go to the dealer so it doesn't void warranty have seen alot of people do this.

 

[grizzstang]

^^^There is more to it than that with the new trucks, the PCM is locked, so you either need to have it unlocked or get a new unlocked PCM. Both would be noticed by dealers if they looked hard enough and would definitely have warranty implications.