Unusual engine operation

[morrpar]

I am posting this to find out if anyone else has experienced similar engine operation.
In normal driving, with a light load on the engine, I experience a intermittent sound/feel that seems much like the engine returning to normal mode after being in ECO mode (cylinder deactivation). The ECO mode indicator light is not on at these times.
In fact, this truck only goes into ECO mode when coasting. Once I apply the throttle from a coast, ECO mode light goes off and I hear/feel the boom or bump of the deactivated cylinders returning to normal operation.
But at times with light throttle, I hear/feel the same noise or vibration that is experience when the ECO mode goes off. This does not happen under medium to heavy throttle.
This happens even when ECO mode is turned off (gear selector). It also happens in tow/haul mode.
I have my first dealer oil change coming up, so I will have them look at it. I just wanted some context from anyone else who has experienced this.

Thanks,

 

[vincentw56]

Do you have eTorque?

 

[morrpar]

Indeed

 

[Rick3478]

I was going to suggest maybe an artifact of the ATM system, if your truck is so equipped.

 

[vincentw56]

It is possible that depending on when it happens in light throttle, it could be the eTorque going into regen mode.

 

[morrpar]

Great thoughts, thanks.
I wish there was some type of display that indicates the status of the Etorque system. It would be nice to know when it kicks in to contribute and when it is introducing a drag on the system.
Other than auto-start, the times when I feel Etorque operation the most is during braking. It reminds me of the exhaust brake on a diesel. Not as strong, and you have to initiate it by light brake application, but you can really fell the braking force being applied that is not in proportion to the force being applied to the brake pedal.
I hope to find out more About what I have been experiencing. I will share any pertinent information.
thanks agin!

 

[morrpar]

By way of an update: Had the truck to the dealer for 10,000!? mile oil change and tire rotation. I also had them check the issue that I described above. The service writer said that there was a "massive" update to the software that "should take care of it". They did not take the time to actually test drive the truck to:
1. Verify the issue.
2. Verify that the update resolved the issue.
As you might imagine, no change; I still have the same intermittent, odd "surging". I will go back to the dealer and try to get an answer.

 

[Darksteel165]

eTorque regen is really strong.
I notice it as soon as I take my foot off the gas if i'm going under 50mph (I think).
It feels like i'm slamming on my breaks when I take my foot off the gas, enough that the truck jerks me forward. Going over 50 and it's silky smooth.

I don't have ECO mode enabled and I don't use start stop so I think i'm getting a lot worse mpg in city driving since i'm just essentially breaking whenever I take my foot off the gas.
Lots of times I will need to touch my peddle ever so slightly or else my truck will slow down too much below the speed limit on roads.

All that said there have been several updates for eTorque that need to be applied by the dealership that affect the regen breaking and also the start stop features.
Pre-update after start-stop my truck would bounce forward, and now after updates it just sits there (unless I put my foot on the gas).

It only takes 10 minutes to do. I had a dealership do it on the whim for me and I just waited outside for 15 minutes and it was done.

 

[morrpar]

I guess my experience with eTorque is a bit different. When coasting, I would have told you that the eTorque does not re-generate.
It seems counter-intuitive, since when I am coasting, I am not necessarily braking. I am coasting-not accelerating and not braking. I am using the energy that was expended durring acceleration to get me on down the road. Not sure regeneration durring coast is in keeping with the purpose of the system-to increase efficiency.

I can't find anything in the manual that explicity explains the sequence of operation for the eTorque system. Most scources, however, indicate that in fact, during coasting, the eTorque does regenerate. This is from a dealer website:

The eTorque system uses a three-stage regenerative braking system that is based on how you are driving and applying the brakes.

• When coasting or applying the brakes lightly – The eTorque system does not use the disc brakes on the truck. Instead, the truck is slowed by friction from the eTorque motor, capturing energy from the vehicle.
• When applying the brakes normally – The eTorque system is used in combination with the conventional brakes. Your brakes will do most of the work to slow your vehicle down, with the motor capturing energy too.
• When braking hard – The eTorque regenerative braking system is not used at all when you have to slam on the brakes, such as when making emergency maneuvers.

So, I do not sense the eTorque regen-ing durring coasting. However, I do feel it when I apply the brakes lightly. And it seems that I can use that eTorque regenerative braking (in part) to slow the truck pretty well. It seems possible to modulate the force by varying the pressure on the brake pedal.

I have never experineced the agressive slowing force that DarkSteel165 discribes in coast mode.

Byond that, the experince that I am describing happens on light-to mid-light throttle, not coasting or braking. It is so similar to when MDS turns off and the four cylinders resume operation, that I gotta assume it is some spurious MDS operation. If I could find the harness to unplug the solenoids for MDS, I would perform a little experiment...

Back to the dealer. Thank for your help!

 

[Louhound88]

Is it possible you're in eco mode at times when the light isn't on? That sounds like how mine handles when in eco mode. I can be in mode and slightly hear it, but with light acceleration I can stay in eco while accelerating for a few seconds, then have it sort of "pop" back into 8cyl mode.

What you can do to test, is turn off eco mode for a few days/week to see if the problem still happens. Just every time you get in your truck hit set the gear selector to 8, and it will keep it from going to eco. Not sure if this still works for 22's, but mine is a 21 and it keeps me in 8cyl mode at all times when I set it like this.

 

[Darksteel165]

The eTorque system uses a three-stage regenerative braking system that is based on how you are driving and applying the brakes.

• When coasting or applying the brakes lightly – The eTorque system does not use the disc brakes on the truck. Instead, the truck is slowed by friction from the eTorque motor, capturing energy from the vehicle.
• When applying the brakes normally – The eTorque system is used in combination with the conventional brakes. Your brakes will do most of the work to slow your vehicle down, with the motor capturing energy too.
• When braking hard – The eTorque regenerative braking system is not used at all when you have to slam on the brakes, such as when making emergency maneuvers.

So, I do not sense the eTorque regen-ing durring coasting. However, I do feel it when I apply the brakes lightly. And it seems that I can use that eTorque regenerative braking (in part) to slow the truck pretty well. It seems possible to modulate the force by varying the pressure on the brake pedal.

I have never experineced the agressive slowing force that DarkSteel165 discribes in coast mode.

You are probably just used to it.

If you drive another pickup truck of a very similar build you would notice the Ram feels extremally heavy and wants to slow down.
Generally I need to gently apply breaks going 20-45mph. With the Ram and eTorque I don't really need to use my breaks at all.
Also being behind people going downhill, the truck should fly and need to brake, but instead I go slower then the car\truck in front of me (who is using their brakes).
If we are going 50+mph downhill I do need to use my brake but under that I don't.

It's kind of like driving a really old car on the highway and turning over drive off.
Soon as I take my foot off the gas it's just starts slowing down right on the spo. If I put my foot on the gas at 1% just so it sees it, the truck rolls like you would expect.

There has been several updates to eTorque via software from the dealership that does greatly change the way it functions so it's possible yours might not be attempting to regen as hard as mine is but that's just a guess.

 

[morrpar]

Great thoughts, friends-thank you.
Regarding the thought about the eco mode test, I have done that test. It does not seem to make any difference with it on or off.
My truck will only enter eco mode when coasting. As soon as you apply the slightest throttle, the light goes off and the feel/sound is the usual "returning to 8 cylinder" operation feel/sound.

The unusual operation that I experience that feels/sounds like eco mode turning on and off (and the eco light does not illuminate) happens only at light throttle. At light throttle, the engine seems to intermittently have the feel/sound like eco mode engaging and disengaging.
I have been experimenting with eco on and eco off; tow/haul on and two/haul off none of these changes seem to make a difference.

I have also been trying to observe general engine/transmission operation to see if it may be something unrelated to eco or eTorque.
So far, it is so similar to eco mode, that I am pretty sure that it is the eco mode engaging/disengaging without the eco light illuminating.

On the eTorque system, my experience is much different than DarkSteel. When I let off of the throttle, the truck will coast like any other vehicle that I drive.
I have had this truck since September. The previous truck was a 6.4 gas 2500. I would say that this truck would coast longer than that truck did.
I do not feel any slowing until I touch the brake pedal. If I lightly touch the brake, the eTorque seems to impede forward movement a bit and then with greater pressure, I get into the service brakes.

The dealer did do an update when it was in for this issue two weeks ago. The truck drove differently for most of a day (seemed slower) but eventually seemed to "learn" my driving patterns and returned to familiar operation.

I plan to go back to the dealer and insist that WE go on a test drive, so that I can point out the issue. I will keep you posted.

 

[Louhound88]

Great thoughts, friends-thank you.
Regarding the thought about the eco mode test, I have done that test. It does not seem to make any difference with it on or off.
My truck will only enter eco mode when coasting. As soon as you apply the slightest throttle, the light goes off and the feel/sound is the usual "returning to 8 cylinder" operation feel/sound.

The unusual operation that I experience that feels/sounds like eco mode turning on and off (and the eco light does not illuminate) happens only at light throttle. At light throttle, the engine seems to intermittently have the feel/sound like eco mode engaging and disengaging.
I have been experimenting with eco on and eco off; tow/haul on and two/haul off none of these changes seem to make a difference.

I have also been trying to observe general engine/transmission operation to see if it may be something unrelated to eco or eTorque.
So far, it is so similar to eco mode, that I am pretty sure that it is the eco mode engaging/disengaging without the eco light illuminating.

On the eTorque system, my experience is much different than DarkSteel. When I let off of the throttle, the truck will coast like any other vehicle that I drive.
I have had this truck since September. The previous truck was a 6.4 gas 2500. I would say that this truck would coast longer than that truck did.
I do not feel any slowing until I touch the brake pedal. If I lightly touch the brake, the eTorque seems to impede forward movement a bit and then with greater pressure, I get into the service brakes.

The dealer did do an update when it was in for this issue two weeks ago. The truck drove differently for most of a day (seemed slower) but eventually seemed to "learn" my driving patterns and returned to familiar operation.

I plan to go back to the dealer and insist that WE go on a test drive, so that I can point out the issue. I will keep you posted.

I agree with how your eTorque works. Mines the same way, and I don't have any braking feeling when coasting, only when I start to apply the brake do I feel extra braking from the eTorque. But normal coasting is like any other truck I've had.

As for the eco feel with the light off, I wouldn't be surprised if that's happening. I know I have 3.21 gears but I do have heavier tires and my truck still slips into eco mode pretty often. So long as I don't use cruise control I can get into eco mode traveling at highway speed. Driving in town I'll get into eco quite a bit, and sometimes I can very lightly accelerate while in eco before it pops out with a more noticeable than usual pop. With my exhaust I can tell when I slip into eco mode just from the change in tone and it'll do it pretty often. Never paid much attention to the light to see if it matches but seems like it does.

I tend to drive pretty spirited. Stop signs and red lights I'll take off quick and let it get higher in RPM than what i would consider "normal" driving. Not full on flooring it but getting on it somewhat. So my learned transmission lets me stay in gears longer without needing to force it. If I have a week or so where I ease up and drive calmly I'll find it wants to short shift more and keep me out of the higher RPMs. At times I'll want to accelerate and feel i'm in a gear too high, but it'll take an extra second or so before dropping gear. As if it wants to be sure I planned to accelerate and drop a gear. But even those times it's a different feeling than popping in and out of eco mode.

 

[morrpar]

Great input Louhound! I am trying to evaluate the circumstances when I feel the anomaly. Getting other's experiences helps me to focus on or dismiss certain things. I wonder if any of the OBD devices that are available would give me better data, real-time. I could then see (hopefully) when ECO is engaged. And possibly see eTorque operation.
Just wondering what the capabilities of these tools are?
Anyone that has used an OBD tool or tuner for trouble-shooting please chime in!

Thanks all!