I am under the impression that our cars have the variable cylinder management. Lately I have been noticing that when the engine switches between these modes I can feel a jolt or shudder throughout the car. This is only felt while cruising on the freeway and when I try to speed up for passing or even when I lightly feather the gas pedal to keep up with faster traffic. I know this is not from the transmission trying to downshift because the RPM barely changes. It has started to become more frequent. It is a 16 RLX SH with 19k miles now. Any ideas? I called the dealership about this and I am scheduled to take it in next week.

 

I think George Knighton had a similar issue. I do not feel this transition at all. I can only tell by looking at the instant mileage when I'm at low throttle, cruising on the highway.

 

In my case, your symptom was one of other symptoms that I experienced.

It led to my car being out of commission for about a week while they imported VCM rocker arm assemblies, and they just replaced everything to do with it.

It has fixed the issue, so far, and the car performs excellently.

There is no TSB for this, but there is an advisory that all dealers should be able to access.

There is anecdotal information that the issue will pop up here and there across a wide range of J Motors with VCM, and there is anecdotal information that it might somehow be related to oil additives that Honda did not anticipate that dealers would use even though Honda advises against it.

Again...that's anecdotal, and should not be presented as absolute proof of anything.

The information is there, but there is not enough information to know anything other than that the issue just pops up every now and again.

And just because that's what the problem was in my case does not mean it is the same problem in your case.

Because you have a KC2, I am discounting the transmission cooling TSB as irrelevant.

When you are in normal mode (not Sport Mode), and you put your foot down, does the car take a while to respond or is it almost instantaneous, like within ¼-½ second?

 

Prepare for a loaner car. :-)

 

Check out this Acura Service News article:

B16060G - Engine Intermittently Rattles or Runs Rough with MIL Blinking?

https://acurazine.com/forums/third-g.../#post15791387

 

Thank you. That sounds like the bulletin to which Karen Radley's service department referred.

 

I would not say VCM is totally transparent. In that 30 - 60 mph range, cruising steady I could feel the VCM. It took awhile for me to identify the sensation as I do not do a lot of highway cruising these days. As I mentioned in another thread, when VCM engages all cylinders I would feel a slight 'tug', somewhat like a smooth gear shift. And when EV transferred to ICE I would sense a slight 'bump' as if someone barely bumped my rear bumper. These power shifts would occur when there was a slight incline in the road, or I applied slight throttle. It is blended very well, considering all the power sources and the dynamic configurations the car chooses. I think the 30-60 mph range is where the most opportunities are for the car to 'relax' ICE power, but that is also a range where wind resistance, road incline or increasing throttle will re-engage ICE to all cylinders (or by switching from EV to ICE). Several Honda J series owners I know with VCM have all commented that VCM is noticeable and only became more obvious as they became familiar with the car's driving sensations. And that without being a torque vectoring AWD hybrid. The Odyssey and Pilot owners may have more obvious experience with this as their profiles are less aerodynamic and drag situations more frequent, thereby affecting VCM.

All that said, I have not heard any rattle or felt vibrations. Nor have I experienced any warning lights. The J series owners I have discussed this with never mentioned that either. So I would summarize without the vibration or rattle, simply noticing the VCM would be normal. But should the symptoms be greater - definitely pursue the TSB.

Am I the only SH driver that perceives VCM this way? It may be more transparent to Bob as his lead foot likely keeps all cylinders engaged a greater percentage of his driving experience! *ducking behind sofa*

 

yes I do feel a lag upon application of pedal input. I had mentioned that on this forum a while back.
this new anomaly is more of an obvious tug like downshifting although the transmission is in the same gear and hence I chalked it up to VCM engaging all cylinders. The only other way I can tell something has changed is that the fuel efficiency meter goes down to 25 or so..

 

This has been more so an issue over the last 2k miles or so...previously i could tell VCM engagement only by noticing the chnages in the fuel efficiency meter. Now I can feel it and can consistently reproduce it by letting the car cruise and have the cyliders deactivated and then slightly feathering the pedal to engage all cylinders. Also it is worse when it is cold.

 

This seems to describe the issue...although there is no lights
and I would call it more of a jerky feeling than a pronounced rattle. But great info to discuss with the service advisor.
I hate how they are always dismissive and in their head are thinking "user error" when these concerns are brought up.

 

I am one that agreed with you on your other post......
I can feel it every time it engages, or disengages.
It does not bother me, because I have no rattles or vibrations.

 

Definitely check with dealer, especially since you can re-create. You have more miles than I do, so it may have developed with mileage. Please do keep us posted as to any diagnosis. There are only about 500 of these cars on the road (US) so I expect Honda would be very interested in repeated reports.

 

Yes you did pgeorg! But I am old and cutting back on caffeine.
I too expect what we sense is normal for VCM. But watching for a pattern developing and also mileage impact. VCM is in PAWS models too, but SHs have other non traditional sensations with power shuffling. This is one attribute of new tech cars where I miss my former RL. That car was so smooth, even with a pokey transmission and that version of the J series engine was like a Rolex watch. In 10 years it never sputtered, vibrated, revved inconsistently or delivered odd sensations.

 

Ha! Who are you kidding, your memory is exceptional.......

I totally agree with you. My 2012 TL SH-AWD was the same, that 3.7L V6 was extremely smooth and powerful. If I remember correctly that engine did not have VCM.....

My SH has 15,000 miles right now, and its one year old.......hopefully the engine will not develop the VCM rattle any time soon.

 

I never had any lights come on, either.

 

The 3.7 in the 6-6 did not have VCM. But I think the 3.5 in the automatics had VCM

 

^^
I don't think either the 3.7, or the 3.5 used in the TL had VCM. I could be wrong though.....

 

Honda / Acura models with VCM. But it is incorrect on the model years for the RLX SH.

 

^^
I saw that, but I don't know how much I trust wikipedia.....
All the documentation on Acuranews.com have no mention of VCM on the 2009-2014 TL.

 

Here's the quote from American Honda's press release at the time of the 4G TL's introduction.

I was checking it out just to see. I must remember wrong, because if it'd have had VCM, I think they'd have mentioned it as a part of what they were at the time calling good fuel economy for the performance level.

 

4G TL.... Damn, that was a really great car for its day.

I wish they'd been more popular.

 

Yes they were, George! I traded mine in with 68,000 miles in 2014.

 

More than 41,000 on the Blackbird, and no issues at all regarding the VCM engagement. I still get a kick out of driving it every time. It is the only car I have ever driven that feels like it is supercharged, but isn't. Very unique.

 

'Cuz 'murica! That's what we do here. All kidding aside, I've never felt VCM activate. I appreciate your description of the sensation. Never felt it. Is it time that Hondacura included a description of the sensation of VCM activation to cover those who are susceptible to noting it?

 

My first experience with VCM was in an RDX loaner. Same conditions, cruising steady across the bay causeway. First I noticed the MID mpg's jumping up, no sensation. Then when the mpg's dropped to typical level, I could sense all cylinders kick in with that slight 'tug' I speak of. This cycled a dew times as I cruised @ 50 mph steadily. If I had not noticed the MID readings, I may not have noticed the sensation,,,or at least not so immediate when driving a vehicle I was not familiar. I would think if you are cruising north of 60 mph, VCM is less likely to kick in, or at least not many on / off cycles.

 

Because of this thread, I watched closely as I put 300+ miles on the SH-AWD this weekend. Mostly highway, mostly steady 65-75 mph. I could definitely see the MID instant-mpg gauge going up and down as I went from slight inclines to slight declines and vice-versa, all while the tach and speed stayed as constant as I could keep it. But try as I might, I could not actually feel anything as the instant-mpg changed. So either my aging senses have gotten muted, or I'm not doing it right.

 

Fsmith you should let it be, because once you sense there is no forgetting it :-)

 

It is like seeing a bear in the woods. Once you see one, then they follow you around all the time.