Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Trouble Shooting/Problems/Service (http://www.jeepgarage.org/f107/)
-   -   Rumbling Noise (http://www.jeepgarage.org/f107/rumbling-noise-68484.html)

bill_de 11-26-2013 10:17 PM

Rumbling Noise
 
I thought the sub woofer was going as I was getting a rumbling noise. It isn't very loud, but it is such a low tone I can feel it slightly in the steering wheel.

So, I eventually turned off the radio, but it didn't stop. It's a low rumbling noise that comes and goes for no apparent reason. It is not speed related. If I go at a steady speed (cruise control) and the noise starts, slightly pressing the gas pedal for a second makes it stop for a short time, but then it comes back.


:confused::confused::confused:



---

Peter_K 11-26-2013 11:09 PM

Since you have the 5.7 I'm willing to bet its MDS activation you're describing. It changes the engine and exhaust harmonics and you'll sometimes hear it as a bit of a rumbling noise and can sometimes feel it. When you press down on the accelerator you're deactivating it as you're putting more load/demand on the engine and the PCM is commanding it off until it re-senses a stable low/steady load situation.

bill_de 11-27-2013 07:14 AM

Re: Rumbling Noise
 
A couple of things. I have almost 6,000 miles on the Jeep and it just started doing this a few weeks ago.

Would MDS be doing this at 25 mph?



----

TurboRush 11-27-2013 08:01 AM

Yes it will. I wish I could turn it off personally... Feels exactly what you would expect if a 4 cylinder was trying to move a 2.5 ton truck along at 1200rpms. My avalanche had MDS too, should have known it drive me nuts again... Just give me all 8 cylinders all the time!

bill_de 11-27-2013 10:23 AM

Re: Rumbling Noise
 
I went out this morning and turned eco mode off. The car was as quiet as it used to be with eco mode on.

I guess I'll turn eco mode off every time now.



Thanks to both of you for the input.


---

Peter_K 11-27-2013 10:39 AM

Eco mode doesn't just strictly affect the transmission shift schedule. The engine will tend to go into MDS operation easier and more frequently (and stay in it more) with Eco mode enabled.

jeepman917 11-29-2013 07:21 AM

Re: Rumbling Noise
 
So - I've had the same issue - driving me crazy since July. I have to agree - its MDS - and - I find that by shutting ECO down it makes it less noticeable - less frequent - especially on acceleration at slow speeds (traffic). I not only find it to have minima the problem - I believe the car is more enjoyable to drive - with a feeling of more 'direct' power. In sport mode - I feel and hear growl - but not as much acceleration if you will.

ECO off is my new go to for daily driving.. try it ...

I find no difference in gas mileage - on or off.

bill_de 12-03-2013 03:42 PM

Re: Rumbling Noise
 
I stopped by my dealer yesterday and had one of the techs drive my Jeep. He confirmed it was the MDS. He said if enough people complain to Jeep they may raise the speed that it will first become active. He said it can kick in at 21 mph as it is now. It is strange that I never noticed it for the first 5,000 miles.

I agree, Eco off is the new normal, except maybe out on the highway.


---

not_too_shabby 12-03-2013 11:11 PM

Quote:

Originally Posted by bill_de (Post 939778)
I stopped by my dealer yesterday and had one of the techs drive my Jeep. He confirmed it was the MDS. He said if enough people complain to Jeep they may raise the speed that it will first become active. He said it can kick in at 21 mph as it is now. It is strange that I never noticed it for the first 5,000 miles. I agree, Eco off is the new normal, except maybe out on the highway. ---

I wonder if they prevent it from coming in before 5000 miles to make sure the engine doesn't break in unevenly?

jeepman917 12-31-2013 07:31 AM

It's possible. I didn't notice it until.around 5k miles. I won't drive the car with eco on now. Love the way it performs with it.off... how much extra gas could.I.be using? Negligible I'd say...

bill_de 02-06-2014 09:24 AM

Re: Rumbling Noise
 
Quote:

Originally Posted by jeepman917 (Post 952553)
It's possible. I didn't notice it until.around 5k miles. I won't drive the car with eco on now. Love the way it performs with it.off... how much extra gas could.I.be using? Negligible I'd say...

I just came across something in the manual that may have something to do with the MDS not making itself known right away.

"NOTE: This system may take some time to return to full
functionality after a battery disconnect."

Maybe we just need to disconnect the battery every few thousand miles, and won't have to remember to turn eco off every time we start up. :lol: Actually it has become habit. It's the damn exit/entry button I keep forgetting.


---

jeepman917 02-08-2014 01:43 AM

Interesting.... I'll tell you though, when I forget to shit Eco off I'm reminded within the first minute of driving by the way the jeep performs and rumbles.... I then hit Eco and I'm good.. Annoying... I bet some don't even notice it.. Also wonder if the rumble is pronounced based on driving habit and how the vehicle adapts...


All times are GMT -5. The time now is 09:00 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community