Dodge/Jeep Hemi DOD

[Sleek-Jet]

I found a late model Grand Cherokee that has checked all the boxes, but I didn't realize that these later model V8s from Stelantis had displacement on demand.

Any feed back on the system, can you disable it by changing driving modes in the car or is there a box (like is available for GM) that plugs into the harness and turns it off for good?

I guess, like GM, the ultimate solution is a cam and lifter change.

I'm also not so concerned with the VVT, since frequent oil changes are the ticket there. Just don't know a whole lot about these engines.

 

[Bigbore500r]

They USED TO MAKE an OBD-II plug in similar to what is used on the GM stuff, to keep the "MDS" system off on the mopar stuff.
For some reason, it's no longer available anywhere i can find!

https://www.rangetechnology.com/products/discontinued_product/parts/RA004?srsltid=AfmBOoq2OQ0ZgRifhKjceOf4KLG089wYehn6MGid0QQjEov-lor9J40t

The Hemi motors have a separate issue from the the typical "AFM" style lifter failure (collapse of the plunger mechanism) - They suffrer from poor oiling of the camshaft at idle / low rpm, causing the lifters to die an early death in vehicles that are idled alot. Check the engine hours of whatever your buying - if they are disporportanately high for the mileage, move on to the next candidate or get the expended warranty!

Other known issues seem to be fuel injector failures, i know a few people who have been thru that. The dealer will try to hit you out of warranty for 8 new injectors and the entire fuel rail assembly, as they don't want to troubleshoot or risk a come-back. Easy fix ,but something to know.

 

[JUSTWANNARACE]

I found a late model Grand Cherokee that has checked all the boxes, but I didn't realize that these later model V8s from Stelantis had displacement on demand.

Any feed back on the system, can you disable it by changing driving modes in the car or is there a box (like is available for GM) that plugs into the harness and turns it off for good?

I guess, like GM, the ultimate solution is a cam and lifter change.

I'm also not so concerned with the VVT, since frequent oil changes are the ticket there. Just don't know a whole lot about these engines.

Just take it out of OD and the MDS/ECO mode will not kick in. I have an '11 GC with the 5.7 and that's how I drive it cause the ECO mode drives me nuts. That reminds me, I should probably go drive that thing it's been sitting for months

 

[JUSTWANNARACE]

I have 9ver 200k or close to it on mine all I've had to do is a water pump and heater core. Ohh and a blend door actuator. I do my oil changes every 3k.

 

[Sleek-Jet]

Thanks guys, this is a 2022 with about 30k miles on it, if I get it I think I have a fighting chance... LOL.

 

[JUSTWANNARACE]

They tow great too. I've towed my Carrera with a bunch also.

 

[84miller]

I have 6.4 with the 6 speed auto trans. In tow mode it disable's MDS (Mult-displacement system) which tursn off 4 cylinders (same ones every time not random). I can also take it out of MDS using the manual selection on the gear shift it allows me to select gear 6. That being said, I also have a 2006 300 c with the 5.7 with MDS. Saying that, both MDS systems have worked without issue. Things to do to make them work smoothly. Check your owner's manual and see what gas is required. The 5.7 must have only 89, nothing else period. The 6.4 in my Ram 2500 must have 87 nothing else. Also allow a little warm up time on starting as in park MDS is disabled. Never allow the engine to be turned off if it is out of park. Lastly, most of the engine failure occur when people are driving on the highway and are in 4-cylinder mode and get off to get gas or food or just stop without getting it back in 8-cylinder mode. Rule either put it in park and let it idle a couple of minutes or down sift a gear and put it in 8-cylinder mode of and drive a while. You need to warm up the head/valve for a few minutes on the non-functioning 4 cyclinders as the heads are alumina values are harden steel. Heads heat up quicker, the valve clarence is minimal and the colder valve drops through the headed head.

 

[CLdrinker]

I have 6.4 with the 6 speed auto trans. In tow mode it disable's MDS (Mult-displacement system) which tursn off 4 cylinders (same ones every time not random). I can also take it out of MDS using the manual selection on the gear shift it allows me to select gear 6. That being said, I also have a 2006 300 c with the 5.7 with MDS. Saying that, both MDS systems have worked without issue. Things to do to make them work smoothly. Check your owner's manual and see what gas is required. The 5.7 must have only 89, nothing else period. The 6.4 in my Ram 2500 must have 87 nothing else. Also allow a little warm up time on starting as in park MDS is disabled. Never allow the engine to be turned off if it is out of park. Lastly, most of the engine failure occur when people are driving on the highway and are in 4-cylinder mode and get off to get gas or food or just stop without getting it back in 8-cylinder mode. Rule either put it in park and let it idle a couple of minutes or down sift a gear and put it in 8-cylinder mode of and drive a while. You need to warm up the head/valve for a few minutes on the non-functioning 4 cyclinders as the heads are alumina values are harden steel. Heads heat up quicker, the valve clarence is minimal and the colder valve drops through the headed head.

This

 

[Bigbore500r]

Thanks guys, this is a 2022 with about 30k miles on it, if I get it I think I have a fighting chance... LOL.

Extended warranty and send it!

 

[spectras only]

Just take it out of OD and the MDS/ECO mode will not kick in. I have an '11 GC with the 5.7 and that's how I drive it cause the ECO mode drives me nuts. That reminds me, I should probably go drive that thing it's been sitting for months

Wife's car is a 2010 Grand Cherokee, 85k miles on it. Yes, take it out of 'D' and use 5th as final drive cruising around town. I only use the overdrive on highways. The GC with its all wheel drive, fuel economy is no better in 'D' than taking it out of O/D.
Hemi is no longer offered, which is a shame. The Hemi GC tow capacity is 7200lbs, which is great for most trailerable boats in the 5000/6000 lbs range on the trailer. 21 foot boats like my old 20 Spectra, wouldn't feel it being behind it.