kurek
Senior Member
- Joined
- Aug 7, 2019
- Posts
- 2,662
- Reaction score
- 3,815
- Location
- Northwest
- Ram Year
- 2015
- Engine
- Hemi 5.7
I wanted to add here since we're talking MDS there is also the little eco indicator on the instrument cluster that reports when you're driving in a fuel conserving way. I'm not here to debate how closely that is or isn't related to MDS operation but I think it would be hard to argue that MDS operation and the eco light are not both looking for similar conditions.
I have outfit slightly larger than stock tires on my truck and before I corrected the tire size in the PCM the truck would almost never display "eco" when traveling 60+ mph (GPS reported) and even when it was on, even the slightest dip in the road or gust of wind would cut it back off. As I said before I can't hear any change with MDS on my side exit exhaust so I don't know what that was doing.
After correcting the tire size in the PCM, the behavior of the eco light is unmistakably much more consistent. If the MDS uses some of the same criteria to choose when to operate then it adds another reason to calibrate your truck for bigger tires, beyond just having an accurate speedometer and odometer.
I have outfit slightly larger than stock tires on my truck and before I corrected the tire size in the PCM the truck would almost never display "eco" when traveling 60+ mph (GPS reported) and even when it was on, even the slightest dip in the road or gust of wind would cut it back off. As I said before I can't hear any change with MDS on my side exit exhaust so I don't know what that was doing.
After correcting the tire size in the PCM, the behavior of the eco light is unmistakably much more consistent. If the MDS uses some of the same criteria to choose when to operate then it adds another reason to calibrate your truck for bigger tires, beyond just having an accurate speedometer and odometer.