How to turn off MDS(cylinder deactivation) for free

[Mcsteve]

TOW MODE disables the MDS!....(or pay $7,000+ and have the camshaft, Lifters and ECM replaced, it's up to you - LOL!)

I’m new to this whole disabling of the MDS but did discover that doing so with the manual shifter helped quite a bit last time I was towing my box trailer (about 4500lb) instead of using T/H mode which changed the shift pattern. How does this impact what you are referencing?

Stephen

 

[392DevilDog]

I agree the original poast is a bit suspect (may turn out to be harmless at best) but I still am not sure why there is a such an urge to turn MDS off. I have had my Ram for almost 8 years and I don't even notice it but I do know that without it your gas mileage will suffer. Also for the guy who has the fuel sender error, it may indicate other issues other than no MDS. I had that error and it was due to critters chewing the wiring as well as the gas tank. I don't like riding around with error messages since they tend to pile up and then you're driving a piece of junk. For me at least, when it breaks, I fix it. Everybody else can do what works for them.

The fuel level sensor only affects my gas gauge. But. It sets the check engine light. Which turns MDS off.

Many here have replaced it only to have it go bad again. Fuel pump is fine. I use the trip meter as my gas gauge.

I check my stored codes once a week...just to make sure one did not sneak in.

Thanks for the concern.

 

[JoeCo]

I agree the original poast is a bit suspect (may turn out to be harmless at best) but I still am not sure why there is a such an urge to turn MDS off. I have had my Ram for almost 8 years and I don't even notice it but I do know that without it your gas mileage will suffer. Also for the guy who has the fuel sender error, it may indicate other issues other than no MDS. I had that error and it was due to critters chewing the wiring as well as the gas tank. I don't like riding around with error messages since they tend to pile up and then you're driving a piece of junk. For me at least, when it breaks, I fix it. Everybody else can do what works for them.

I turn it off because I find it extremely noticeable (and have in all 4 of my rams, stock exhaust or not). Between vibration/noise/feel I can't stand when MDS kicks in.

It's just one of those things some people notice and others don't, but if you do it can drive you crazy so we just turn it off.

 

[Zoe Saldana]

Hello Everyone,

I recently came across a product video that also had an interesting bit of information in it. You can quickly and easily cycle the MDS(cylinder deactivation) on and off.
Check it out here: Turn off MDS(cylinder deactivation)

Let me know if you guys have any other features that you found in the comments below.

-LifeinOverdrive

Isn't it easier to put it in tow/haul?

 

[ramffml]

Isn't it easier to put it in tow/haul?

Easier if you find 3 seconds is too long, yes, but TH changes your shift points which will be a plus/negative depending on your preference. I don't like TH when I'm not pulling, because hanging onto 6th or 7th gear for 30 seconds longer than needed seems... excessive.

 

[mikeru]

I agree the original poast is a bit suspect (may turn out to be harmless at best) but I still am not sure why there is a such an urge to turn MDS off. I have had my Ram for almost 8 years and I don't even notice it but I do know that without it your gas mileage will suffer. Also for the guy who has the fuel sender error, it may indicate other issues other than no MDS. I had that error and it was due to critters chewing the wiring as well as the gas tank. I don't like riding around with error messages since they tend to pile up and then you're driving a piece of junk. For me at least, when it breaks, I fix it. Everybody else can do what works for them.

It's a preference thing for me. And MDS is more noticeable on some trucks than on others, especially if you've done any exhaust upgrades. I always turned it off on my previous truck. Even when it had stock exhaust it was very pronounced. I could not only hear it but feel it too. On my new truck I haven't been turning it off very often. That's because I wasn't really able to tell when it was active. I disabled the ECO light for a while, and I really couldn't tell when it was active. Lately though I've started noticing it more. Not sure why, but I've started disabling it again because of that. If fuel economy is affected I haven't noticed it.

 

[Farmer Fran]

So, if permanently disabling MDS is bad, and tow haul disables MDS...what about the people that only use them to tow. I know a couple of people that tow more than 95% (probable more like 99%) of the time the truck is moving.

 

[392DevilDog]

So, if permanently disabling MDS is bad, and tow haul disables MDS...what about the people that only use them to tow. I know a couple of people that tow more than 95% (probable more like 99%) of the time the truck is moving.

It is the same as 87 vs 89 vs 93 octane. Or brand of oil. Or oil change interval. Great things to argue/conversate about.

 

[jmc921]

How much does mds save you?

I have never done any hard comparison - running through a tank with and without MDS - but, when I had a warning light on and the MDS wasn't working, I seemed to go through about a half a tank (26 gallon tank) in only a few days of fairly short trips. Normally, I barely see the gauge move over the same time frame and similar usage.

 

[jmc921]

It's a preference thing for me. And MDS is more noticeable on some trucks than on others, especially if you've done any exhaust upgrades. I always turned it off on my previous truck. Even when it had stock exhaust it was very pronounced. I could not only hear it but feel it too. On my new truck I haven't been turning it off very often. That's because I wasn't really able to tell when it was active. I disabled the ECO light for a while, and I really couldn't tell when it was active. Lately though I've started noticing it more. Not sure why, but I've started disabling it again because of that. If fuel economy is affected I haven't noticed it.

That's the bottom line, your own personal preference. Also, I don't see how disabling MDS can damage the engine. Makes no sense to me but maybe there is some sort of computer/electrical issue. I can't see how it can affect the engine at all.

 

[Docwagon1776]

I've seen this several times, when I engage t/h mode on my 2017 Bighorn, it does not disable MDS. Only manually selecting gears does. Am I missing something?

It's just a difference in having the 8 speed vs the 6 speed. I *think* every year of the 8 speed requires you to use manual gear select, but the older 6 speed will allow for either.

 

[boblonben]

Hello Everyone,

I recently came across a product video that also had an interesting bit of information in it. You can quickly and easily cycle the MDS(cylinder deactivation) on and off.
Check it out here: Turn off MDS(cylinder deactivation)

Let me know if you guys have any other features that you found in the comments below.

-LifeinOverdrive

Don’t no need to.

 

[mikeru]

I've seen this several times, when I engage t/h mode on my 2017 Bighorn, it does not disable MDS. Only manually selecting gears does. Am I missing something?

You have a 4th gen. MDS is not disabled by using T/H mode for your truck. On 5th gens it is disabled if you use T/H.

 

[Zoe Saldana]

So, if permanently disabling MDS is bad, and tow haul disables MDS...what about the people that only use them to tow. I know a couple of people that tow more than 95% (probable more like 99%) of the time the truck is moving.

They are going to die!

 

[Docwagon1776]

So, if permanently disabling MDS is bad, and tow haul disables MDS...what about the people that only use them to tow. I know a couple of people that tow more than 95% (probable more like 99%) of the time the truck is moving.

There truck explodes, obviously.

 

[Dusty]

And we're supposed to believe what you say why?

Why in the world would they design an engine in such a was as to be damaged at the time when it's working the hardest (towing or hauling)?

I agree with you that everyone should at least try to do their own research on things rather than believe what people say in a forum. But your first two sentences are doing exactly what you said not to believe.

Agree. This claim doesn't make any sense for a number of reasons besides the very point you're making.

The lifter receives oil in two ways: the internal hydraulic operation is oiled through the pushrod, and the lifter body is oiled by an oil gallery on the bottom side of the lifter. Oil flows to the lifter roller from oil pressure surrounding the lifter body in the lifter bore. Both occur irrespective of being in MDS or not in MDS.

NOTE: You can see a fairly good demo of this at [ gen 3 Hemi Lifter camshaft failure Uncle Tony ultimate battle finale - YouTube ]. The commentator unfortunately is long-winded appears to be in some sort of pi!!ing contest with someone else.

There are at least two randomness features involved in this problem. At least two surveys of owners reporting which cylinder's lifter caused camshaft lobe damage (I believe one was on this site). One [The Fatal Flaw of the 5.7L Eagle Hemi V8 Engine Fully Explained (2009+ Lifters and Camshaft Failure) - YouTube] documented over 700 lifter failures and found that ALL cylinders reported lifter failures, MDS and non-MDS. The narrator states that in his survey the one cylinder that had the most failure reports was number 5, which is not even an MDS cylinder.

Then there's the one random issue that never seems to be addressed: why the vast majority of MDS engines DO NOT experience a lifter failure? And although there is no empirical evidence, the figure that gets the most attention is that these lifter failures occur in "five percent" of vehicles. If true, how are the other 95% of Hemis not experiencing the issue?

Of the several tech's that I've talked to, the only thing they are in agreement on is that Hemi lifter related issues have diminished considerably over the last year.

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: 064560 miles.

 

[CMG1012]

Dusty, so you’re the kid in class everyone copied the homework from, haha. Thanks for all that info.

 

[Dusty]

Dusty, so you’re the kid in class everyone copied the homework from, haha. Thanks for all that info.

Thanks, but I was just as likely to be found standing in a corner!

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: 064568 miles.

 

[farout75]

You have a 4th gen. MDS is not disabled by using T/H mode for your truck. On 5th gens it is disabled if you use T/H.

My 17 RAM with almost 102000 miles on it, has worked perfect when its in 4 cyc mode. I can only tell when the green light comes on/ I have on occasion put the gear selector in 3rd or 4th when I was in mud or deep snow. I see no advantage in wanting it disabled. If a better sound is what you want then change out the mufflers, then you have the best of both worlds.

 

[Octane]

My 17 RAM with almost 102000 miles on it, has worked perfect when its in 4 cyc mode. I can only tell when the green light comes on/ I have on occasion put the gear selector in 3rd or 4th when I was in mud or deep snow. I see no advantage in wanting it disabled. If a better sound is what you want then change out the mufontrol slectorflers, then you have the best of both worlds.

My 4th gen disables in tow/haul and with the range selector.And it is optimal from an i.c.e. standpoint to run off all cylinders.But the manufacturer did say the extra wear on the shutdown cylinders were negligible.But it can of course last many trouble free miles anyway.(In response to the statement about no advantage to disabling mds)