2016 5.7 Hemi, 1500 truck.......clattering from MDS

[DonFitzwater]

Any software updates available for my mom's 2016 1500 4x4 with 5.7 hemi/auto? VIN is 3C6RR7LT6GG359085

Truck runs great at speed but at low speeds in hilly terrain the engine clatters like violent pinging when in 4 cylinder mode. This only happens under load and not when cruising. My dealer is less than capable and unless I can find a TSB they won't even know where to look. Thanks

 

[TFucili]

Have not heard of that one. You can prevent it from going into MDS mode by using the shift switches and selecting top gear, at least that's how it worked for my 2500.

 

[DonFitzwater]

Have not heard of that one. You can prevent it from going into MDS mode by using the shift switches and selecting top gear, at least that's how it worked for my 2500.

This one behaves very differently than my 2500 with the 6.4 (my 2500 had a horrible drone/violent transition at low speeds from the MDS but was cured with a software update). I can't seem to turn off the MDS at all. It's all dependent on throttle setting and at part throttle/high load like climbing a hill at low speed, the clatter is significant, more so just before the engine switches back to 8 cylinder mode. Highway cruising is great.

 

[TFucili]

So, if you use the gear switches and set it to 6 or 8, depending on trans, in the EVIC it still goes into MDS mode?

 

[DonFitzwater]

Dealer just called. They said I have to run premium fuel.....................We'll see how things go after we run premium for a while.

EVIC doesn't tell me when MDS is active or not, it's all by ear and seat of the pants feel. The dash is pretty basic in this truck. It's very obvious when it's happening.

 

[JR]

Dealer just called. They said I have to run premium fuel.....................We'll see how things go after we run premium for a while.

EVIC doesn't tell me when MDS is active or not, it's all by ear and seat of the pants feel. The dash is pretty basic in this truck. It's very obvious when it's happening.

I am not familiar with year to year changes but I almost daily drive a 14 Hemi/8spd auto. LOTS of idle time and LOW speed, off highway driving. That truck has never seen anything but 87 octane and it's yet to have an engine related issue. I can check the engine hours/mileage tomorrow if you would like.

On the EVIC, it does say "Eco" when MDS is active. If your newer rig doesn't I'd really question why. That's just odd!

 

[TFucili]

I think you have to enable the Eco light via the settings. But I thought even the lowest trim/EVIC would indicate what gear you have selected if you use the ERS or whatever they call the up and down arrow buttons. On the various gasser forums, folks have been avoiding the dreaded MDS by selecting the top gear for a long time it seems. It should then utilize all available gears, but not use MDS???

Doesn't the owners manual say 89 Recommended, 87 Acceptable? I call bull on needing premium.

 

[JR]

I think you have to enable the Eco light via the settings. But I thought even the lowest trim/EVIC would indicate what gear you have selected if you use the ERS or whatever they call the up and down arrow buttons. On the various gasser forums, folks have been avoiding the dreaded MDS by selecting the top gear for a long time it seems. It should then utilize all available gears, but not use MDS???

Doesn't the owners manual say 89 Recommended, 87 Acceptable? I call bull on needing premium.

I should have mentioned trim. It is an Express, as far as I know the bottom of the barrel. And I'm not certain for sure but I'm pretty sure the Eco mode is default. Which is contrary to what Don is saying. I can verify tomorrow if it will help.
One thing I can absolutely verify is, this truck has seen nothing but 87 it's entire life with zero effect aside from possibly mpg.

 

[DonFitzwater]

There is a blurb in the owner's manual that details running mid-grade fuel or premium for best engine performance and that running regular can cause engine pinging and no harm will be done.

Truck is now filled with premium and isn't pinging any more during the MDS operation. I will add this, the truck has been in Cordova, Alaska all summer and has been running coastal regular which is garbage brought up from Washington so there is no telling what kind of fuel quality we had. We ran all the old gas out two days ago driving from Whittier to Fairbanks and then filled up on premium after the dealer visit. She's running like a champ. I will also mention that not all regular unleaded fuels are created equally. Regular in western canada is much higher octane that regular in Alaska. My sleds run much better on the canadian juice.

 

[Ozymandias]

And only use 5W-20 Oil in MDS engines.
Heavier weight oils make the MDS go nuts.

 

[Wayne M.]

Don, exactly what oil is in it? Any check engine light? Is it using oil? May I suggest pulling the plugs and looking for oil deposits?
My ‘14 Durango stays on all 8 with the eco button hit and not lit up. And yes, the book does call for 89 octane.

 

[TFucili]

And only use 5W-20 Oil in MDS engines.
Heavier weight oils make the MDS go nuts.

6.4s come with 0W40, and tons of people run 5W30, I ran 5W40 to try to keep the dreaded tick away, and never a CEL.

 

[JR]

I'm surprised a N/A engine - a V8 at that - in today's tech - calls for 89. Even Ford's little mini power plant 4 and 6 cylinder DI turbo engines can do it on 87.

 

[TFucili]

My 6.4 got a steady diet of 87, even pulling heavy, and never pinged or had issues. MDS is a waste.

 

[Wayne M.]

I'm surprised a N/A engine - a V8 at that - in today's tech - calls for 89. Even Ford's little mini power plant 4 and 6 cylinder DI turbo engines can do it on 87.

All the American V8’s ping and rattle. I hear them weather GM, Chrysler or Ford. I think I hear Tahoes rattling away from traffic lights the most. Pinging real bad.

 

[DonFitzwater]

Don, exactly what oil is in it? Any check engine light? Is it using oil? May I suggest pulling the plugs and looking for oil deposits?
My ‘14 Durango stays on all 8 with the eco button hit and not lit up. And yes, the book does call for 89 octane.

We run Mobil full synthetic 5w20 and change oil in 4K mile intervals. No check engine lights and no oil consumption. Drove it around today and she’s quiet as a mouse and snappy. Premium has done the trick.

 

[JR]

All the American V8’s ping and rattle. I hear them weather GM, Chrysler or Ford. I think I hear Tahoes rattling away from traffic lights the most. Pinging real bad.

I wonder if what you hear is related to variable timing. Ford 4.6 and 5.4 are pretty noisy at idle at operating temps. When it was new I brought the wife's 4.6 back in because it just sounded horrible at idle. Cold start, the engine was whisper quiet, once up to temp the cam phasers would get really noisy. The mechanic reassured me that it was normal and they all do it. He even took me out and started his personal truck with over 100k miles. It sounded identical to ours. 10 years and 150k miles later....it still sounds horrible
But she runs like a top.

 

[Wayne M.]

JR, when I’m in traffic, I’m always looking and listening. Missing wheel fasteners and auto stop freak me out.
Anyway, I hear these things when the light goes green. The fuel knock and noises out of these newer vehicles are disturbing. If I ever hear my 5.7, it’s when I whip it on a hill. I have some short, steep ones around here.

 

[sag2]

My 14 Hemi never made a sound and I ran 87 except when towing. Even if I ran 87 towing it never pinged. The knock sensors allow a little more timing if you run higher octane.

 

[DonFitzwater]

FYI- Mother in law has driven from Fairbanks to Northern California on premium and reported no clatter and 1-2 mpg better than average.