The new GC with Hemi

Thanks for the articles. I wrote to DC as follows:

DaimlerChrysler Customer Assistance Center P.O. Box 21-8004 Auburn Hills, MI 48321-8004

Attention: Alan Falkowski

Gentlemen:

I recently purchased a new, 2005 Jeep Grand Cherokee limited with the HEMI(R) MDS engine option. My VIN number is:

1-------------------------. I took delivery of the Vehicle last Friday 12/10/04 from Smith Haven Automotive Group, St. James, NY.

There are two things I feel during acceleration in the range of approximately 1700 to 4000rpm:

1) Acceleration is uneven. With steady throttle pedal pressure, the vehicle accelerates unevenly with bursts of power similar to that of a 2 stroke motorcycle power band. This is not to be confused with normal shifting of the transmission. This is a real unevenness with bursts of power at different intervals from 1700 rpm through 4000rpm with a steady, even foot. 2) During acceleration multiple, mini interruptions in power or hesitations occur. Although these hesitations are minor, they are frequent during acceleration and noticeable. It almost feels like the motor may be hindered by some type of malfunction in the MDS system or that normal operation of the MDS system may cause the engine to hesitate.

The above conditions occurred from the first time I drove the vehicle.

The vehicles check engine light came on within 15 minutes of driving it off the lot at Smith Haven Auto Group in St. James, NY. I returned the vehicle and they reset the light which came on as soon as I left the lot for the second time. I dropped off the Jeep the following day. The dealer spent almost 2 full days trying to determine the problem. I reported the hesitation to them as well. They had told me that they had been on the phone with your engineers and had determined that a chaffed wire behind the engine block, connected to the MDS system may have been the culprit. I visited them while they worked on my Jeep and saw that they had the entire top section of the motor apart.

The check engine light is no longer illuminated but both the problems I mentioned above still exist.

I am not a letter writing wacko. I'm concerned. My vehicle feels as if it can't be trusted. I believe unreliable is the term I'm looking for. If there's a problem that Chrysler engineers are aware of, that's fine with me. Just keep me informed and I'll wait out the fix. I will even volunteer as a guinea pig if it will help them resolve these issues. If there are no similar complaints than I'm afraid I may have a vehicle which I am almost certain has some huge power train issues that were there prior to purchase.

Please pass this message along to the Chrysler Engineering staff so that this issue gets the attention it most likely deserves. I am also willing to part with the vehicle for some time if Chrysler wishes to inspect the vehicle further.

On a side note; I am pleased with the Dealer and their efforts to accommodate me. Special thanks to Tim Burk who has made buying a new Jeep a pleasant experience. I am also pleased to own a new Jeep with such cutting edge technology. Let's try to work out these bugs together.

Patrick proclaimed:

At that point the bank explains the terms "with recourse" and "without recourse" to you.

I'm even more sure you don't.

Mike Romain proclaimed:

No, not that bad. Different technology, somewhat more reliable by being a rather simple trick.

I think he got a lemon, either as a dealer or a vehicle. I know of 4 vehicles with the 8/4 hemi and none of them have any troubles. One driver wasn't even aware they had a variable displacement engine. Plus have hotrodded the Hemi GC at the lo cal dealer myself and it has no hesitation I can detect. And loves onramps.

The fuel delivery system is much more advanced than the GM effort. Sounds like he might have a problem with the fuel delivery system, though...

Check to make sure they didn't pull the bulb on the Check Engine light.

Just curious:

Have you heard of any failures with the lifters yet? Given their "role" in the whole cylinder deactivation scheme, I'm concerned with their longevity. I can't imagine that the lifters are cheap to buy, either.

I tend to keep vehicles for quite a long time, so I'm mostly concerned with hefty repair bills when vehicles get over the 100,000 mile mark.

-John

Not the same engine Bill. The one they stick in the Jeep tries to run on 4 cylinders by shutting down the valve lifters with oil cut off solenoids. They starve them for oil so they collapse and the engine staggers along on 4 cylinders.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

"L.W.(ßill) Hughes III" wrote:

Here's a description of GM's version of MDS. I saw an acticle about Daimler's in the past, but darned if I can find it now:

The relevant text is a follows:

"Currently, we could disable just the fuel delivery," says Meagher, "but the valves would still be opening and closing and each cylinder would still be doing work pumping air in and out. So there would be no net gain in efficiency--you wouldn't have eliminated the pumping losses at all."

and:

"We disable the valves through a device called a switching lifter," explains Meagher. "This differs from a normal lifter in that there is an inner body and an outer body connected by a spring-loaded pin. For V-8 operation, the pin is fully expanded by the spring so the two pieces act as one and the lifter acts like a regular lifter. When we want to disable the valve operation, we deliver high-pressure oil to a groove in the lifter that leads to the outside end of the pin, forcing the pin to collapse the spring. Now the two parts of the lifter are free to move relative to one another and as the cam lobe pushes on the follower the inner portion of the lifter pushes against another spring at the top of the lifter and does not transfer force to the pushrod."

I believe that Eaton developed the lifter and that both GM and Daimler are using it. Don't quote me on that, though...

-John

One word, Never buy a new release vehicules... stay away for at least 1 year....

-- LE CLONE

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snipped-for-privacy@leclone.com

From this site:

Quote: The system deactivates the valve lifters. This keeps the valves in four cylinders closed, and there is no combustion. In addition to stopping combustion, energy is not lost by pumping air through these cylinders. End.

Sounds sweet, eh. LOL!

Mike

"L.W.(ßill) Hughes III" wrote:

So there's a vacuum in the cylinder ?

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

It would be acting like a compression stroke so there would be minimal vacuum as long as the rings were perfect. Get a little worn and I can see severe drag really fast.

Mike

Dave Milne wrote:

As far as the Fly by wire accelerator, My FSM on my Ram 1500 Hemi says to turn the key to the on position and let it sit for >10 secs to calibrate the accelerator. You shouldn't have to do this very often unless the battery is disco'd or a PCM flash is updated.