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Discussion Starter #1
I bought a 2017 Volt last week to replace a 2013 I've had for nearly 5 years. It's a nice upgrade, particularly the longer EV range, improved efficiency, LED lighting, and improved interior/user interface (yay, actual buttons). It drives great on electric, but on gas.....not so much.

The gas engine seems to be running kind of rough. Particularly at low RPMs there's a bit of what feels like hesitation or stuttering. It's improved somewhat since I've been driving the car a while now, but it's still there. My question is: Is this normal? I realize the Gen 2 Volt has a different drivetrain, and this might cause different driving characteristics. But I don't think it should be running this rough.

The car has been sitting around unsold for nine months, so it's hard to say how old the gas may be or what might have happened to it since it was delivered to the dealer. It had 200 miles on it when I bought it, and more than half of them were gas.

I took the car in for service. The tech ran engine diagnostics and found no issues. I don't think they drove it, though. I'm planning to go drive some of the other Gen 2 Volts to see how they compare, but I just wanted to see if anyone else who's driven both have noticed the Gen 2 on gas to be much rougher than Gen1.
 

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I thought I noticed some rough idling sometimes on ours. That has since ceased. They issued a lot of software updates for the 16 for various issues, so I think one of those took care of it. Maybe see if there are any outstanding updates for your 17?
 

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While I don't have many gas miles on my 2017, it seems to run fine when it does switch. I may take it on a trip next weekend that would use gas, I can report back if I do.


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Of the 11,800 miles on my 2017 only 350 are on gas. And I too have noticed the ICE appears to run a little rougher than either my 2012 or 2013 Volt. One might describe it as a "slight studder".

Am hoping with more miles I'll be putting on over the winter due ERDTT that it will smooth out.

But since I put so few ICE miles on or Volt's I guess in the big scheme of things it's not a big deal.
 

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I also went from a Gen 1 to a Gen 2. You're not imagining it--the Gen 2 is a hot mess on ICE compared to the Gen 1.

GM sold Gen 2 as "smooth" ICE operation and I thought it would be even better than my Gen 1. But it's not--it's just got different pluses and minuses. Gen 2 excels in sound isolation (better) and keeping the ICE off much of the time at lower speeds--no more roaring at stoplights and rare operation below 15 MPH. Heck--I've driven up to 4 miles at slow speeds in range extended mode without the ICE starting. For some owners, these improvements might be more important.

But for me, Gen 2's drawbacks bother me more--especially the transmission of the PHYSICAL connection of the ICE to the driver. Gen 2 FEELS like an ICE powered car (because it is). It's a totally different design that abandoned the "serial" hybrid preference of Gen 1. In range extended mode, it's an ICE car masking as an EV--not an EV using an ICE as a generator.

So it shakes, shudders, chuggles, whirrs, flares, and all other kinds of "NORMAL" behaviors--inherent to ICE cars. These are not problems--they are by design.

On the good side, I've got about 1000 miles now on ICE and some of this seems to be smoothing out--although I just noticed the other day how absolutely horrible it was shaking at a stoplight while idling (ICE warm-up). Other Gen 2 owners have said that it gets better over time, so I'm hoping that to be the case.

I believe these issues will only ever be noticed by Gen 1 owners because others coming from ICE vehicles will be so accustomed to these ICE 'characteristics' that they would think Gen 2 is whisper quiet. But we Gen 1 owners know GM can do better....
 

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But for me, Gen 2's drawbacks bother me more--especially the transmission of the PHYSICAL connection of the ICE to the driver. Gen 2 FEELS like an ICE powered car (because it is). It's a totally different design that abandoned the "serial" hybrid preference of Gen 1. In range extended mode, it's an ICE car masking as an EV--not an EV using an ICE as a generator.

So it shakes, shudders, chuggles, whirrs, flares, and all other kinds of "NORMAL" behaviors--inherent to ICE cars. These are not problems--they are by design.
And, i suspect, that's part of the vastly improved CS fuel economy. Gen 2 gets 50 MPG pretty easily, under the same conditions that Gen 1 gets 40. But part of that comes from extracting more miles out of the dino-juice rather than JUST generating and then using up electricity, under changing conditions.
 

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I have over 8000 miles on my Gen II now, about 60% is ICE driving at speeds above 45mph. I don't ever recall hearing the ICE running at low speed or idle. But when the car switches from electric to ICE I sometimes notice some roughness. This has been very intermittant and I doubt it is a problem, but even so, I much prefer the car to be running on electric only. The car is so quiet and smooth normally that when you do get this occasional engine roughness it makes it more noticeable and disturbing to me. Can't wait to have a pure BEV.
 

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I have over 8000 miles on my Gen II now, about 60% is ICE driving at speeds above 45mph. I don't ever recall hearing the ICE running at low speed or idle. But when the car switches from electric to ICE I sometimes notice some roughness. This has been very intermittant and I doubt it is a problem, but even so, I much prefer the car to be running on electric only. The car is so quiet and smooth normally that when you do get this occasional engine roughness it makes it more noticeable and disturbing to me. Can't wait to have a pure BEV.
I have a 2018 LT and mine is very smooth on ICE and electric, of course. In fact you barely notice a change when you switch into HOLD mode. It is very smooth. I have never driven a GEN 1 so I can't compare, obviously. But I have no complaints about my 2018 LT so far.
 

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And, i suspect, that's part of the vastly improved CS fuel economy. Gen 2 gets 50 MPG pretty easily, under the same conditions that Gen 1 gets 40. But part of that comes from extracting more miles out of the dino-juice rather than JUST generating and then using up electricity, under changing conditions.
Good point, and--unlike the Gen 1--they also purposely built the 5ET50 to be easily repurposed to other vehicles, like the Malibu Hybrid. They needed a powertrain that relied more on ICE to handle the load in range-extended mode with minor battery assist.

I believe this is GM's first foray into the modified "e-CVT" realm so I would imagine they will continue to fine-tune the NVH while on ICE. Certainly the software updates handed out to '16 early adopters showed they were still working out some kinks.

Regarding MPG boost, I'm hoping the extra MPG shows up consistently. I get incredible low-speed MPG (up to 67 at one point!) in the Gen 2 but my highway numbers so far (only 1000 miles on ICE) are in the same ballpark as my Gen 1 with the same roads, techniques, etc. My last two ice trips got me to 42, so maybe I'm starting to finally cross the threshold.
 

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I think there is correlation between lack of ice usage and roughness. When new my ‘16 was rough and chugged, but updates and lots of fresh gas miles on trips have yielded a smooth runner at 33K mi. Forget about setting EV usage records and use the ice now and then —and don’t baby it.
 

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there is definitely a difference, it is anything but seamless with my 17. Oddly even when coasting down hill with the ICE engaged I have felt the car be indecisive with how it was managing it. does not seem to matter if I am at highway speeds or not, it should be smooth but you can definitely detect the surging/chuggle/callitwhatyouwill. It reminds of an automatic hunting for the right gear
 

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The experience with my early build '17 (Feb,'16) has been excellent. I have not noticed any rough running ICE miles. Currently have 5000 miles on the ICE. In fact, most of the time, when the ICE starts at highway speed, the only indication that it is actually running is the display changes from battery to gas.
 

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I had a rumor of a chuggle when engaging the ICE at highway speeds for the first 1000 ICE miles or so ... haven't felt it in quite some time.
 

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The experience with my early build '17 (Feb,'16) has been excellent. I have not noticed any rough running ICE miles. Currently have 5000 miles on the ICE. In fact, most of the time, when the ICE starts at highway speed, the only indication that it is actually running is the display changes from battery to gas.
It's these comments that make me wonder if there are some variations with the manufacture of this drivetrain that require more "break-in" for some owners than for others. Maybe it also has something to do with how long a Volt is sitting around without any ICE usage before sale. Mine sat for about 9 months on the lot and has been more bumpy on ICE.
 

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It's these comments that make me wonder if there are some variations with the manufacture of this drivetrain that require more "break-in" for some owners than for others. Maybe it also has something to do with how long a Volt is sitting around without any ICE usage before sale. Mine sat for about 9 months on the lot and has been more bumpy on ICE.
This could make sense, I bought my late model year 2017 when it was still in transit so it was as brand new as could be and it seems very smooth. I don't have many gas miles yet but so far so good.


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Good point, and--unlike the Gen 1--they also purposely built the 5ET50 to be easily repurposed to other vehicles, like the Malibu Hybrid. They needed a powertrain that relied more on ICE to handle the load in range-extended mode with minor battery assist.

I believe this is GM's first foray into the modified "e-CVT" realm so I would imagine they will continue to fine-tune the NVH while on ICE. Certainly the software updates handed out to '16 early adopters showed they were still working out some kinks.

Regarding MPG boost, I'm hoping the extra MPG shows up consistently. I get incredible low-speed MPG (up to 67 at one point!) in the Gen 2 but my highway numbers so far (only 1000 miles on ICE) are in the same ballpark as my Gen 1 with the same roads, techniques, etc. My last two ice trips got me to 42, so maybe I'm starting to finally cross the threshold.
Not to be a Debbie Downer but your improved mpg might be attributable to worn tires, that is, tires with less rubber resulting in less hysteresis loss. You will go back to your earlier numbers when running new tires.
 

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Discussion Starter #19
Thanks for the feedback. Yeah, I appears my Volt does have the chuggle. Hopefully it will continue to improve as a drive it. It's not such a huge deal since I don't drive on gas that much anyway, but I do wish GM could have made a smoother gas drivetrain.
 

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I noticed the same thing when I first got my 2017. What could best be described as a "stutter", particularly at sub-40mph speeds. But after about 3k of ICE driving, it is all but gone. I had read plenty about it here, so I was expecting it. And sure enough like others reported, it gradually went away. Though it took a few months to get that many ICE miles.

The only thing I notice now is the initial switch from EV mode to ICE mode when moving at speed. And also while in ICE mode I can sometimes feel the switching between the different modes (there are 3 driving modes while using gas) particularly when coming to a stop. Though it doesn't feel any different from a auto transmission up/down shifting.
 
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