What Does Honda VCM Engagement and Running "Feel Like"?

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May 7, 2025
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My wife and I bought a new 2025 Honda Pilot Elite in May of this year. We just got home from a round trip to Wisconsin and I realized, I don't know what the Pilot should "feel like" when the VCM is engaged. The one thing I felt on the trip was like the new winter tires were out of balance, but only intermittently, and usually when going up a long grade at highway speeds at just the point before the transmission would downshift. This out-of-balance feeling was in the butt, throughout the entire vehicle, including steering wheel. It was noticeable enough for me to mention to my wife I needed to take the car to Discount Tire while in Madison and have the tires rebalanced. And then I wouldn't feel it again for a while.

The type of road surface didn't seem to matter. I've felt tires out of balance, and what I was feeling just didn't make sense.

What does the Honda J35Y8 engine feel like when VCM is active?

This is the third long trip since we bought the car, and the last OCI I noticed the AMSOIL Signature Series with 5.6k miles was very dark and there was quite a bit of carbon in the oil filter when cut open. There was speculation on BITOG and elsewhere this could be due to having switched to running 87 octane, Top Tier fuel instead of a diet of mostly Shell premium. I made a conscious effort, and a few route deviations, to use only Shell premium with V-Power blah-blah-blah. Octane varied between 91 and 93, with two places showing their premium was ethanol-free. Only once did the car see a different brand, and that's because the Kansas Turnpike Authority has lined their pockets and gave a contract to Love's Travel for ALL the service centers along the turnpike between Oklahoma and Kansas City. I wasn't going to make it to a Shell, so filled up with their premium. On the way home, I filled with Shell right before the turnpike and barely made it to the first Shell station in Oklahoma. The Pilot seems to get about 20-22mpg at sustained highway speeds and an unfortunate headwind (going last week and coming home yesterday and today).

Can extended VCM activation cause carbon deposits? The Amsoil had 150 miles on it before we left on the trip and it's getting noticeably darker (not horrible) in the 2600 miles this past week.

This was the range remaining when we made it to the first Shell station in Oklahoma. I'm not sure the effort to use only Shell premium was worth it. I guess we'll see. Took 16.889 gallons to fill the Honda specification 18.5 gallon fuel tank. I continually preach to my wife about not waiting to fill the tank. This time we both engaged in the "experiment". Glad she was driving, had it failed and we ran out of gas.

Screenshot 2025-11-29 at 15.40.38.webp
 
I can only detect mine kick in on really smooth asphalt. On rougher roads the road noise and normal vibrations drown it out. The sensation is similar to driving on smooth a road with low frequency ripples in surface. My VCM only kicks in at light throttle and lasts a maximum of 30 seconds before it turns off. I suppose the computer is trying to maintain cylinder and catalyst temperatures so it can't leave the cylinders inactive too long.
 
I can only detect mine kick in on really smooth asphalt. On rougher roads the road noise and normal vibrations drown it out. The sensation is similar to driving on smooth a road with low frequency ripples in surface. My VCM only kicks in at light throttle and lasts a maximum of 30 seconds before it turns off. I suppose the computer is trying to maintain cylinder and catalyst temperatures so it can't leave the cylinders inactive too long.
The newer VCMs alternate which cylinders and how many are disabled. It’s possible even when you think the 30 seconds has elapsed, it’s simply changed which cylinders are “dead” and it may simply convince you that the small surge as it changed cylinders was resuming regular operation.
 
I was able to get 30 mpgs with the VCM disabled on our 19 with 90K. 87 octane, top tier sometimes. Next oil change I’ll cut open the filter.
 
Well, after experiencing this, I'd be all over a muzzler if one was available for the 2025 Pilot. I'm starting to believe this is the source of the carbon deposits, not the brand, or even octane, of fuel. The car has very few short-trip miles, so suspect it's spent a lot of time with VCM active. :mad:
 
Take a normal V6 and pull half the plug wires. That’s what it feels like, but with special motor mounts to disguise it.

Get a VCMuzzler or similar device IMO… reciprocating engines are only truly happy when all cylinders are firing, if you pardon the pun.
VCM-4 has no mass made defeat yet as it’s a more complex system. The only known reliable way to defeat it is to drive in Sport mode.
 
VCM-4 has no mass made defeat yet as it’s a more complex system. The only known reliable way to defeat it is to drive in Sport mode.
Wish I'd known this for our trip. I'd have taken the potential fuel mileage hit and drove in Sport mode. I may continue to drive in Normal mode for this OCI to see just how bad the carbon deposits get, but then again, why would I do that to the engine? Based on how relatively dark the oil has already gotten, I'd say there's enough data to know whether the deposits were coming from the use of 87 octane, Top Tier fuel or not. Darn VCM! Now I have to hope HPL's PPPCMO will clean them up going forward (switching from AMSOIL Signature Series to HPL). I'll call Mary Jane at HPL tomorrow and see if she can add a bottle of EC30 to my case of PPPCMO I ordered yesterday.

IIRC, once you turn the engine off after driving in Sport mode, the mode defaults back to Eco or Normal, whichever was selected prior to putting in Sport mode. Muscle memory already turns off Auto Start/Stop. Adding changing driving modes shouldn't take long to add to the MM.

Thank you for the bit of knowledge, @I<oil
 
Feels like nothing honestly except when it engages or disengages in a 2015 Pilot. A light that says Eco indicates it
No light has ever come on showing when active on our 2025 Pilot in Normal mode. Maybe if ECO mode was selected a light might come on indicating you're now in planet-saving mode and the slow destruction of your engine has been activated?
 
No light has ever come on showing when active on our 2025 Pilot in Normal mode. Maybe if ECO mode was selected a light might come on indicating you're now in planet-saving mode and the slow destruction of your engine has been activated?
The destruction of engine stuff is overblown. It happens but not as much as internet shows.
 
No light has ever come on showing when active on our 2025 Pilot in Normal mode. Maybe if ECO mode was selected a light might come on indicating you're now in planet-saving mode and the slow destruction of your engine has been activated?
The eco light is on older models for VCM. Since 2017, the light hasn’t come on anymore.
 
The destruction of engine stuff is overblown. It happens but not as much as internet shows.
Whilst it’s not as prevalent as like GM’s 5.3l or Ram’s Hemi engines dropping lifters and cams, there are forums scattered with piston ring jobs and whatnot. So it is becoming a more prevalent issue unfortunately.
 
Wish I'd known this for our trip. I'd have taken the potential fuel mileage hit and drove in Sport mode. I may continue to drive in Normal mode for this OCI to see just how bad the carbon deposits get, but then again, why would I do that to the engine? Based on how relatively dark the oil has already gotten, I'd say there's enough data to know whether the deposits were coming from the use of 87 octane, Top Tier fuel or not. Darn VCM! Now I have to hope HPL Premium Plus PCMO will clean them up going forward (switching from AMSOIL Signature Series to HPL). I'll call Mary Jane at HPL tomorrow and see if she can add a bottle of EC30 to my case of HPL Premium Plus PCMO I ordered yesterday.

IIRC, once you turn the engine off after driving in Sport mode, the mode defaults back to Eco or Normal, whichever was selected prior to putting in Sport mode. Muscle memory already turns off Auto Start/Stop. Adding changing driving modes shouldn't take long to add to the MM.

Thank you for the bit of knowledge, @I<oil
Oil color is not an indication of “dirtyness”, as things called aminic antioxidants darken rapidly when exposed to high heat.
 
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