MDS turned off

[vetteyog]

New to the Mopar life, I always put my truck in manual mode 6 when I drive it to disable the MDS. What are the advantages or disadvantages of doing this? Does it make any difference in cam/lifter failure issues? Know it is supposed to save fuel but I don't really care about that.

 

[mikeru]

There isn't much data on this but plenty of opinions. Here's just one thread where it is discussed to death. I suggest reading through all 19 pages if you're really curious to know what people think about that subject...

For the guys who think deactivating the mds via a tune is a good idea

=AZXcfuqWYbC_PPIfMwz6Tct1NEi-bxooGBgMOJPipiKmkHcPaPHf6yt_L9edGk5pG-I_jnWJ2GWbIJCihKx86jt6riMu1aUpLlDdjK5dRqjxnZDD9moF3DUfyJVgtPgrtspfQGHN97CXnaEwevkNEv2wjK3rrSfIu9kGULTQIRFCIvdTcKD1cMBV8O5LXTixPZFei1XGVk-smlITIajlOy3sfqNDkf92cz5hXnR1G4grpHEtcZudtXX1cThisKciZyTgKxZd77OqIYPyelhXwQid&__tn__=-UC%2CP-...

www.ramforum.com

 

[vetteyog]

There isn't much data on this but plenty of opinions. Here's just one thread where it is discussed to death. I suggest reading through all 19 pages if you're really curious to know what people think about that subject...

For the guys who think deactivating the mds via a tune is a good idea

=AZXcfuqWYbC_PPIfMwz6Tct1NEi-bxooGBgMOJPipiKmkHcPaPHf6yt_L9edGk5pG-I_jnWJ2GWbIJCihKx86jt6riMu1aUpLlDdjK5dRqjxnZDD9moF3DUfyJVgtPgrtspfQGHN97CXnaEwevkNEv2wjK3rrSfIu9kGULTQIRFCIvdTcKD1cMBV8O5LXTixPZFei1XGVk-smlITIajlOy3sfqNDkf92cz5hXnR1G4grpHEtcZudtXX1cThisKciZyTgKxZd77OqIYPyelhXwQid&__tn__=-UC%2CP-...

www.ramforum.com

Thanks!! Now I'm really torn on what to do !

 

[mikeru]

Thanks!! Now I'm really torn on what to do !

You're welcome! Hey, you're the one who asked

 

[62Blazer]

Maybe MDS does cause lifter failure, but it's all speculation and theory. For every person who makes a post that MDS is the cause of lifter failure there is a person who posts and states it's idling that causes the failures. There have also been several posts from people stating they had a lifter failure but it was not on an MDS cylinder.

 

[JHoward]

Thanks!! Now I'm really torn on what to do !

Well, from what I'm understanding from what I've read here in the RAMforum, is to let the normal function of MDS operate to allow for better oiling of the "Drama Queen" HEMI's internals, lifters/cam.

I've drove around in my HEMI most of my ownership(2017)with MDS manually selected "off" and now I let it do its MDS thing. All is still good for the moment.

Less idle time is an good practice to do, as that's also a "bad thing".

"Drive it like you stole it" is the helping concept for possibly longer HEMI engine life, leave Paw Paw Skibblebanks at home.

Hammer down and happy motoring!

 

[DILLIGAF]

The idle thing is nonsense. every stock HEMI in Alberta would be dead by now. Everyone idles for hours up here for months on end.

Its the low rpm set at the factory, combined with the garbage oil they recommend that probably ***** the engine up.

Bumping it to 750rpm give 50psi at idle with factory pump.

 

[JHoward]

Good note, however not everyone has invested in a tune to bump up the idle speed or install a higher volume oil pump, so therefore wouldn't it be worthy for those folks to reduce idling for long periods?

 

[Wild one]

Thanks!! Now I'm really torn on what to do !

If you didn't watch this video,spend the 16 minutes it takes to watch it.

Is MDS Damaging Your HEMI? The Answer May Surprise You!

I feel like MDS has been unfairly made the culprit for the lifter failures we see on Gen 3 Hemi engines. In this video I explain exactly how the system works...

www.youtube.com

 

[huntergreen]

IMHO, mds does not cause lifter failure. If mds mode bothers you, invest in a tuner that will delete mds mode. Me, I don’t notice when it’s on or off so I just let it do its thing. Drive and enjoy your Ram. If I do drop a lifter and wipe out the cam, my dilemma will be which cam to use to get a little more oomph! or stick with stock under lifetime warranty. I’m sure Wildone can guide through this if I have an old man crisis.

 

[Mojo88]

MDS on my truck sucks, it sounds like a farm tractor when MDS kicks in. For me, it's gonna be MDS off all the time, either manually for each drive, or a Diablo tuner at some point to shut it off for good.

I change oil/filter every ~3K, so maybe that will help.

 

[diymirage]

Good note, however not everyone has invested in a tune to bump up the idle speed or install a higher volume oil pump, so therefore wouldn't it be worthy for those folks to reduce idling for long periods?

Would you be able to bump idle speed with alfaOBD ?

(I plow with mine and it would be nice to keep the alternator spinning)

 

[DILLIGAF]

No

 

[diymirage]

Boo!

Thanks

 

[Docwagon1776]

The idle thing is nonsense. every stock HEMI in Alberta would be dead by now. Everyone idles for hours up here for months on end.

Few vehicles idle more than police cars, but fleet data doesn't show hemis dying left and right. They tend to outlive the transmission. Fleets use oil that meets spec, but they aren't doing top shelf synthetics and additive packages. Electronic gremlins were the most prevalent issue by far over the years when I had access to fleet data.

Note the news stories about Indiana State Police and the oil coolers for the Durango sidelining their fleet. Their vehicle before that for years was the hemi equipped Charger. If the Durango failures are newsworthy you could be sure Charger failures would be as well.

 

[Docwagon1776]

New to the Mopar life, I always put my truck in manual mode 6 when I drive it to disable the MDS. What are the advantages or disadvantages of doing this? Does it make any difference in cam/lifter failure issues? Know it is supposed to save fuel but I don't really care about that.

Advantage: Saves a small amount of fuel, reduces emissions by a small amount. *May* effect oiling in a positive way.

Disadvantage: Some trucks have some level of vibration. Some have none. 8 speed trucks seem to be more likely to have noticeable vibration, and if you have rock rails or anything that stiffens the frame it will amplify it a bit.

Aftermarket exhaust may sound worse.

That's it. It's just something guys like to complain about to complain about for the most part.

 

[mikeru]

C'mon guys, this has been discussed to death in other threads. Lets not rehash it all over again. The OP's question has been addressed.

 

[Ken226]

The idle thing is nonsense. every stock HEMI in Alberta would be dead by now. Everyone idles for hours up here for months on end.

Its the low rpm set at the factory, combined with the garbage oil they recommend that probably ***** the engine up.

Bumping it to 750rpm give 50psi at idle with factory pump.

My employer has a fleet of about 100 pickups and SUV's, of various brands. About 1/3 of them are Rams and Durangos, all of which have the 5.7 Hemi, ranging from 2015 up to 2021 year models. They get huge amounts of idle time.

I checked the EVIC about a month ago on a 2015 Ram, and it has over 9,000 hours of idle time. Not a single one of them has had a cam failure yet. They all get 5000 mile oil changes at the local Jiffy Lube type place, using whatever oil and filter the lube place cares to put in.

Edit to add:

According to their website, my employers oil change place uses Mobil 1.

 

[huntergreen]

No

How do you bump up idle ? Thanks

 

[Wild one]

How do you bump up idle ? Thanks

Tuner,or a rock on the skinny pedal,lol