Yes, Diablo has had the tuners out for years on the hemi. For the 09 Ram, Chrysler has put up roadblocks to make it harder to change. Some ECU pathways are full of digital nonsense to make it impossible to decode without the proprietary tuning equipment. I guess you could always use a higher viscosity oil to shut it down.

 

Yes, I have the 5.7. The reason I found it strange was because I did not have any such issue in my 06 Charger R/T which also had the 5.7 with MDS. I even had aftermarket headers and exhaust and when the MDS kicked in it still didn't cause as much vibration/buzzing sensation as I feel in my truck. There is definitely a different pulse going through the exhaust when MDS is active, but I wouldn't have thought it would cause this issue.

Dr. Bill, I agree with you that I can also feel it through the steering wheel and the floorboard. The gas pedal was just the most obvious place.

Based on what I am seeing here it appears to be normal though. So I'll not worry about it. I was concerned perhaps a part could be in the early stages of failure (such as a bearing).

Secret Agent Man, you are correct about them doing a great job as far as making the activation of MDS almost seamless. It's very much improved compared to my Charger.

 

For somebody who has the "Fuel Saver" indicator, do us a favor. I'm curious about this. On the LX cars, you could keep MDS off simply by staying in autostick. As soon as you switched to the autostick mode, it immediately turned off MDS and would not come on if you stayed in autostick mode (or Electronic Range Select (ERS) as they call it now). I would be anxious to see if the trucks are the same way.

 

When you take the same engine and shut down half of its cylinders and turn it into a 4 cylinder motor, you greatly increase the number of resonance frequencies you need to filter out.

Good point, I would like to add to it if I may. Your concept is sound; however it is also possible that switching the number of active cylinders changes the frequency (as opposed to quantity) of engine vibrations. Since objects resonate to frequency, different objects will become excited as engine vibrations (and all those harmonics) vary. Despite mathematical attempts to predict all this, real world effects often produce unanticipated results. Your gas pedal vibrations may one of those mathematical escapees For what its worth, I have not experienced anything of this type in my regular cab 09.

 

could it be a vibration caused by something else then? or maybe we just have motors with "better" frequencies then the others?

 

It is actually a bit sticky, things such as different cab configurations (different interior dimensions) can become significant variables. It can be a pretty involved study and way out of my area of expertise so I wouldn't even hazard a guess. Now, I do know the result of pressing that pedal all the way to the floor

 

The chassis mounts are completely different on a standard cab than they are on a crew cab truck. Each wheelbase, powertrain and cab configuration is tuned independently. NVH is tricky stuff.

 

just to mention, i was under the truck putting my steps on and i saw large, round pieces of cast iron(?) mounted to the body via rubber. i am only assuming they are to help dampen vibrations?

 

I do not have the MDS indicator light. I tried the auto stick technique and saw no difference in the buzz. IMO, if it is MDS induced, the trucks don't kick MDS out in auto stick mode. Somebody with a light, let us know on the stick please.

 

Yes, they're big ugly mass dampers. I am tempted to take them off and see just how bad it feels.