No kiddin'! And I thought I was patient... Hemi09Challenger R/T, driving mostly in autostick won't affect your warranty. You should try that if you want to stick with your car. I know I would've thrown the towel at the second engine replacement: what an inconvenience, warranty or not, and how can you trust the car? Sorry to hear about your troubles, man...
I'm really confused with this issue. We've been speculating our heads off, but the same 'weak' chain goes into a lot of other Hemis and only the Challenger autos seem affected. We blame the MDS, but other models have it too and seem trouble-free. The Challenger autos (many daily drivers and commuters) probably see more miles than the manuals (many garage queens and weekend toys), that's a given, but what about the Chargers? Those get driven a lot (I put 20K miles a year on mine and imagine the highway patrol ones). Does the Challenger have a different MDS setup? What gives?
Again, the most depressing thread on CT makes me think of going 6-speed (or even Pentastar!) for my next ride when it's an automatic I need (and a V8, um, make that a Hemi)...
That is a good summary of what we know so far. The one thing I can think of that could potentially explain the specificity to auto Challengers is the simple matter of mds handover threshold in the programming. If they decided to run a distinctly different threshold in the Challenger version of firmware, that could be the culprit out of all of this. It's not that mds is present or that mds is operating, but something as simple as mds tapping-out at the 70 hp mark vs say 55 hp in previous Hemi cars (numbers just chosen as an example). ...or maybe the difference is the lower rpm bounds that would trigger a tap-out? I think this is worth some consideration. Of course, if there is no difference in thresholds between Rams or Chargers or Challengers, then it is a dead end idea.
It's not that I really needed 370 hp...but having 150+ hp riding shotgun at a moment's bidding w/o a 6000 rpm moonshot is what makes me feel like I'm in the right car for me. The roar of a v8 seals the deal!
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Last edited by randycat99; 08-10-2012 at 01:56 PM.
My car has 63000 miles on it and the timing chain broke cruising at 70mph on the highway.... Since it is now out of warranty I am having to make the repairs myself in hopes that my engine hasnt grenaded. I recently purchased the Manley timing chain set part #73205 which I was told would be compatible with my engine....tried to install new part tensioner bracket would not fit....called Manley tech support where they tell me that it will not work on the engines with MDS. I was under the impression that all the later engines have this. I am now looking for a stock upgrade because the stock timing chain looks like it belongs on my lawnmower. Any help will be appreciated.
My car has 63000 miles on it and the timing chain broke cruising at 70mph on the highway.... Since it is now out of warranty I am having to make the repairs myself in hopes that my engine hasnt grenaded. I recently purchased the Manley timing chain set part #73205 which I was told would be compatible with my engine....tried to install new part tensioner bracket would not fit....called Manley tech support where they tell me that it will not work on the engines with MDS. I was under the impression that all the later engines have this. I am now looking for a stock upgrade because the stock timing chain looks like it belongs on my lawnmower. Any help will be appreciated.
My condolences to another victim. You fit in the typical scenario. And the Manley setup won't work for you, that's true, it's been discussed earlier here. As for that chain, I hear ya, but they use the same in the SRT models so I doubt it's the issue. I'd look into upgraded tensioner parts (Chrysler), but at least one failure has been reported with those already. Since out of warranty you can disable the MDS with a handheld (tune) or run your car in autostick mode from now on.
The one thing I can think of that could potentially explain the specificity to auto Challengers is the simple matter of mds handover threshold in the programming. If they decided to run a distinctly different threshold in the Challenger version of firmware, that could be the culprit out of all of this. It's not that mds is present or that mds is operating, but something as simple as mds tapping-out at the 70 hp mark vs say 55 hp in previous Hemi cars (numbers just chosen as an example). ...or maybe the difference is the lower rpm bounds that would trigger a tap-out? I think this is worth some consideration. Of course, if there is no difference in thresholds between Rams or Chargers or Challengers, then it is a dead end idea.
I'll buy that because what else could it be? We've discarded the bad parts batch theory a long time ago due to the spread in the cars affected.
I gotta say that the MDS seems to come on right around 65 mph, and I believe is still on at 70 mph, depending on the load, on my Charger, however (I can't be too sure because I've driven my car in autostick for most of its life... and especially lately). They probably set the MDS to be active for the average mileage conscious commuter (around the speed limit). But it could still be a programming difference that's Challenger-specific.
As for that chain, I hear ya, but they use the same in the SRT models so I doubt it's the issue.
Just to clarify. The 2008-2010 SRT's used a different timing chain and tensioner, the strongest of the bunch. The new 392 is based on the 5.7L engine and thus it uses the same chain and tensioner. We won't know if the 392's are affected with this issue until some begin getting up there in mileage.
I'll buy that because what else could it be? We've discarded the bad parts batch theory a long time ago due to the spread in the cars affected.
I gotta say that the MDS seems to come on right around 65 mph, and I believe is still on at 70 mph, depending on the load, on my Charger, however (I can't be too sure because I've driven my car in autostick for most of its life... and especially lately). They probably set the MDS to be active for the average mileage conscious commuter (around the speed limit). But it could still be a programming difference that's Challenger-specific.
Mind you, I was speaking particularly of engine load, not vehicle speed, even though the numbers could be mistaken as such. I really do mean 70 horsepower vs 55 horsepower, as examples. These could occur at any sorts of vehicle speeds, actually. 65 hp, by the reading on my ScanGauge, mds seems to be working pretty hard. I've never seen 70 hp in mds, as the threshold probably resides right in that area, hence the transition happens before my SG can read it. At 50 hp, mds is just lightly humming away, but not particularly strained.
As far as vehicle speeds in my Challenger, I've seen mds operate at anywhere from 20 mph to 80 mph. I am typically at 65 mph on the hwy (it's rural TX, after all) with mds, and the engine load at that speed could vary anywhere from 20 hp to 65 hp, depending on the particular scenario. Lately, I am more cognizant of proactively activating full-v8 mode by around 60 hp, I'm guessing. Usually, I am actually watching the instantaneous mpg read-out for if it falls below the 20 mpg mark. 20 mpg probably maps to 60-ish hp when in top gear at hwy speeds...point being, I'm not using mds to do any straining on 4000 lbs of car as far as hills or accelerations. It's all light duty use whenever mds is running, which also coincides with when it is pulling in those 25-30 mpg numbers.
Last edited by randycat99; 08-10-2012 at 03:05 PM.
I sold my 2006 Charger R/T for my 2010 Challenger. I can say the MDS on the Challenger is way more intrusive, being it activates way more often. Seems the programming to be more aggressive.
First thing the predator did was to disable the MDS.
As a potential/probable buyer I'm wondering if ANYONE here has emailed this thread to Chrysler corporate & asked if they are addressing this problem and what was their response?
Just to clarify. The 2008-2010 SRT's used a different timing chain and tensioner, the strongest of the bunch. The new 392 is based on the 5.7L engine and thus it uses the same chain and tensioner.
Thanks for that, raVenX. I'm still only a prospective owner and therefore a student of the Challenger. I forgot that the standardization is a new development.
@randycat99: yeah, I did notice that you were addressing load, not speed. The second happens to be easier to monitor for us without eco mode or gauge, but I realize that it is not a very good indicator. This is why I often state feeling transitions in & out of MDS more than its actual operation, because besides a little vibration I'm often guessing.
Like you I do get MDS operation at pretty low speeds (in city driving), and it's that 'straining' feeling that makes me nervous and causes me to use the autostick or accelerate out of MDS mode. I've been trying Drive on surface streets only recently due to this thread, because its usually straight to autostick on the freeway offramps for me. I only mentioned the highway speed because this seems to be the accepted danger zone for a crap-out.
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