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Unread 12-22-2011, 02:10 PM   #31
Redboots
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2005 TJ Wrangler 
 
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Just returned from a 700 mile round trip. Left Lake Havasu, Arizona (450' elevation) and drove to southern Utah (elevation 5200'). The GC Overland Hemi turned 1000 miles on the trip. Using 87 octane gas, and driving full time between 65 and 80 mph, the MPG was 20.7 I'm happy with that. Might even do better after it's broken in a little more. BTW, no oil consumption.

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Unread 03-31-2013, 07:17 AM   #32
sim51
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Hi,
Thanks for the information on MDS system. I have a 2007 Grand Cherokee with the Hemi 5.7 V8 in it with only 30,000 miles on the clock and i'm having a misfire on cylinder 1 and the occasional stall at idle, but only when its starting or just started. I'm starting to look fairly hard for answers through forums as i have had most things replaced including PCM lifters and all the common stuff. Do you think it could be related to MDS somehow as its cylinder 1? The car has been in and out, but mostly in the jeep dealership for the last year and a half. This is the thread if you are interested in more info and any help is much appreciated trust me! http://www.jeepforum.com/forum/f67/5-7-hemi-1500784/

Thanks again
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Unread 03-31-2013, 07:42 AM   #33
Redboots
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The GC has about 14k miles on it now. Mileage is still varied between around 15 and 20 mpg depending on driving conditions, speed, etc. (just what you would expect). Oil consumption has gone to zero between 5000 mile oil changes, that's good (it was using about a quart per 1500 miles until the first oil change). My only concern remains that when I have someone follow me on a trip, they always comment on the rather substantial puff of white smoke the tail pipes emit, apparently as it goes to ECO mode. It doesn't do it every time, but pretty frequently. Sometimes it's described as a pretty substantial puff of smoke. My guess is it's unburned fuel as it drops a cylinder, but it just makes GC look cheap and broken when someone is following.
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Unread 03-31-2013, 07:43 AM   #34
CoupeHauler
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Ram2 said "Why would I buy a Hemi to drive 65mph or slower? "

I bought the Hemi to pull a car hauler - wanted the power and HD tow equip - not particularly interested in the high speed aspect the GC offers as the Police seemed to do a good job of taming the wild one in me
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Unread 07-28-2014, 11:44 AM   #35
falconst
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I know this is an old thread but I have a question on the MDS.

Is it possible to have the MDS set so it becomes active when sitting in traffic?
The info states from 12 to 65 mph but I would think that running 4 cylinders while idling and sitting in traffic would also help out.

Also, does the MDS cause a sensation of jerky or sputtering feel while cruising at certain speeds?

Thanks.

2011 WK2 Overland 5.7
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Unread 07-28-2014, 12:31 PM   #36
2014RedHemiGC
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Not possible without extensive reprogramming. Would suspect noise and vibration issues at that low rpm. Totally seamless on my '14.
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Unread 07-28-2014, 12:40 PM   #37
falconst
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Thanks for the update RedHemi,

Thought maybe with the Diablo Tuner that I keep reading about, then again I didn't get the Hemi to sit still. :-)

I'll have to look more into the TSB's to see if any are due on my WK2.
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Unread 07-28-2014, 12:54 PM   #38
hemispin
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Quote:
Originally Posted by falconst View Post
Also, does the MDS cause a sensation of jerky or sputtering feel while cruising at certain speeds?
You can feel it engage and disengage, but it's barely noticeable. It mostly comes on during coasting or very light load.
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Unread 07-28-2014, 01:05 PM   #39
Bullheadbud
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I have a 2013 Ram hemi that has the MDS. Highway cruising speeds 65 to 70 with the MDS or without makes no measurable difference in my mileage. I think it was designed and put there to satisfy pollution standards and not to save on fuel. Good write up though.
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Unread 07-29-2014, 09:16 AM   #40
falconst
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Quote:
Originally Posted by hemispin View Post
You can feel it engage and disengage, but it's barely noticeable. It mostly comes on during coasting or very light load.
Maybe that is what I am feeling.

I have become very sensitive to vibrations and feel of a vehicle especially since I started riding my motorcycle. I am at the point where I can tell when it's time to adjust air pressure, the chain, sprocket wear, etc...
When on two wheels everything MUST be perfect so maybe I am feeling it in the Jeep more than I should.

Thanks for the info.
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Unread 07-29-2014, 04:22 PM   #41
loveracing1988
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Quote:
Originally Posted by Bullheadbud View Post
I have a 2013 Ram hemi that has the MDS. Highway cruising speeds 65 to 70 with the MDS or without makes no measurable difference in my mileage. I think it was designed and put there to satisfy pollution standards and not to save on fuel. Good write up though.
I also have a 2013 Ram, i can see the instant mileage drop by 1 to 2 mpg's shutting off mds, it comes right back up when it is turned back on. Maybe yours isn't engaging because it works great for me.
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Unread 07-30-2014, 02:11 PM   #42
chowner
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Quote:
Originally Posted by falconst View Post
I'll have to look more into the TSB's to see if any are due on my WK2.
That's not how TSB's work.
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Unread 07-31-2014, 09:20 AM   #43
falconst
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Quote:
Originally Posted by chowner View Post
That's not how TSB's work.
I should restate.
I'll check to see if any there are applicable Service Bulletins for fixes to the situations I am experiencing.

I did look and found the "Fish Bite" TSB, 18-035-14, for 2012-2013 Cherokee and Durango. The TSB symptom/condition sounds exactly what I feel occasionally; a surge, shudder / pulsation at cruising speeds.

So it may not be the MSD activation/deactivation that I am feeling but the "fish bite" others are having.
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