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Disabling MDS

JJMalone

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Anyone else thinking of disabling the 392’s MDS ?
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0II392II0

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Yes, but after warranty, from what I read it was more then just a tune.
 
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JJMalone

JJMalone

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I don’t think the tune plays any part in this. 4 cylinders have different lifters and two oil ports. The eco mode lifters have two modes of operation and two oil ports. One oil port fills the lifter like all the others and all valves operate normally. In eco mode the alternate oil port is used, and the lifter is allowed to collapse and not open the valves, but the lifter follows the cam as the lifter has an internal spring that takes up the lash and returns lifter; the pushrods and valves do not operate. Thus, the engine runs on 4 cylinders while the other 4 have non-operating valves. In eco mode the injectors for the non-operating cylinders obviously are not fired either. At least it looks like a better and more robust system than Chevrolet uses on their LS engines. They have an internal pin that locks the lifter for normal run and the pin is retracted in their eco mode and their lifters also have an internal spring that allows the lifter to follow the cam without opening valves. They have had a lot of failures.
 

0II392II0

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I don’t think the tune plays any part in this. 4 cylinders have different lifters and two oil ports. The eco mode lifters have two modes of operation and two oil ports. One oil port fills the lifter like all the others and all valves operate normally. In eco mode the alternate oil port is used, and the lifter is allowed to collapse and not open the valves, but the lifter follows the cam as the lifter has an internal spring that takes up the lash and returns lifter; the pushrods and valves do not operate. Thus, the engine runs on 4 cylinders while the other 4 have non-operating valves. In eco mode the injectors for the non-operating cylinders obviously are not fired either. At least it looks like a better and more robust system than Chevrolet uses on their LS engines. They have an internal pin that locks the lifter for normal run and the pin is retracted in their eco mode and their lifters also have an internal spring that allows the lifter to follow the cam without opening valves. They have had a lot of failures.
From your first post couldn't tell you prior knowledge, seems you are more familiar with the process then I am. This is something I starting skimming information a while ago. It seemed from my searches that problems if they are going to arise, they started showing around plus or minus 100k, some earlier some with out issue. Again this is all going off what I've read, but would like to discus this because this is on my list of things to do at payoff/warranty which ever comes first really. It seemed that the lifters were the moving parts that took the brunt of the system and were failing. Seems there are lifer/cam kits to eliminate the MDS. I do all my own wrenching and have yet to do a cam in V8 so it knocks something off my bucket-list anyway (done more then a bakers dozen on some Harley TC's). I plan on driving this till the brakes fall off or they stop selling fuel, so this sound like something to address before the lifters fail and start the domino effect. Was this something your looking at down the line or relatively soon?
 
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JJMalone

JJMalone

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From your first post couldn't tell you prior knowledge, seems you are more familiar with the process then I am. This is something I starting skimming information a while ago. It seemed from my searches that problems if they are going to arise, they started showing around plus or minus 100k, some earlier some with out issue. Again this is all going off what I've read, but would like to discus this because this is on my list of things to do at payoff/warranty which ever comes first really. It seemed that the lifters were the moving parts that took the brunt of the system and were failing. Seems there are lifer/cam kits to eliminate the MDS. I do all my own wrenching and have yet to do a cam in V8 so it knocks something off my bucket-list anyway (done more then a bakers dozen on some Harley TC's). I plan on driving this till the brakes fall off or they stop selling fuel, so this sound like something to address before the lifters fail and start the domino effect. Was this something your looking at down the line or relatively soon?
No internal work or changing lifters, just disabling eco mode right after delivery. It can be turned back on for any dealer visits for warranty but the lifter running in normal mode should have the same service life as the non-eco lifters if it is never run in eco mode. There are videos of folks doing this with other dodges with the 392.
 

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0II392II0

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What? I'm going to have to look into this, every fuel saver technology I've experienced in any vehicle as been more of a annoyance than anything. If you plan on doing so please share, seems the long term benefits would be greater the sooner it's disabled.
 
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JJMalone

JJMalone

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What? I'm going to have to look into this, every fuel saver technology I've experienced in any vehicle as been more of a annoyance than anything. If you plan on doing so please share, seems the long term benefits would be greater the sooner it's disabled.
I agree. The best fuel saver tech to me would be good engine design running efficiently with the right gear ratio. I'm old school tho.
 

Crawldad

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i had the mds in my 2015 challenger rt. v8. was fine. tons of power. got like 26-27mph highway, but have all the power you need whenever. actually too much power. many many many times i caught myself cruising at 85 and it felt like 65. you will have no shortage of hp or torque or power when you want it.

not sure what you are trying to accomplish. i dont see a purpose or end goal.
 
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JJMalone

JJMalone

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Did you successfully disable MDS?
After driving it a few thousand miles I’ve decided to leave it alone. I’m not too worried about the anecdotal lifter failure tales. After all if all the stuff reported on this forum about the 3.6 was going to happen, by now my ’20 JLR with 91K miles on it should have required new rear main seal, new steering box, new rear axles ‘cuz locker sensors leaked, etc. I don’t think Dodge’s MDS system is the cause of lifter/cam failures. Internal lifter springs allow the lifter to follow the cam and not operate the pushrods/rockers/valves in MDS, and when not in MDS the lifters work normally. I don’t see any more failure risk on this system than if there was no MDS. All the same loading on all the same parts. (I would like to know how much fuel this saves or what mileage improvement they claim for MDS.)
 
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Young04

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After driving it a few thousand miles I’ve decided to leave it alone. I’m not too worried about the anecdotal lifter failure tales. After all if all the stuff reported on this forum about the 3.6 was going to happen, by now my ’20 JLR with 91K miles on it should have required new rear main seal, new steering box, new rear axles ‘cuz locker sensors leaked, etc. I don’t think Dodge’s MDS system is the cause of lifter/cam failures. Internal lifter springs allow the lifter to follow the cam and not operate the pushrods/rockers/valves in MDS, and when not in MDS the lifters work normally. I don’t see any more failure risk on this system than if there was no MDS. All the same loading on all the same parts. (I would like to know how much fuel this saves or what mileage improvement they claim for MDS.)
Did I read that correctly? Your 2020 Jeep has 91K miles on it? How?
 

areuriding

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Look into RANGE Technology. I purchased this for my 6.2 Yukon Denali and love it, simple plug into your OBDII.
 
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JJMalone

JJMalone

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Did I read that correctly? Your 2020 Jeep has 91K miles on it? How?
I'm retired and drive a lot, coast, mountains, shooting spots, remote favorite places, etc.
 

Outrun

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MDS on the 6.4 is not even an issue.
 
 



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