Honda VCM Disabling Questions

[t1snwrbrdr12]

Any Honda VCM disabling knowledgeable people here?

Likely buying a new Honda w/ v6 and VCM. I’ve never liked the idea of cylinders shutting down on anything. At least Honda doesn’t seem to have mechanical failures (lifters) that can still arise even if VCM is disabled. I know they clog up and get sticky piston rings, but if it’s disabled and well maintained I would think this is a non-issue.

My concern is all the VCM disables are simply skewing the coolant temp. I’ve tried to read up on it. Some claim they have a “processor” that tricks the coolant temp, but still relays the actual temp at the same time? I’m not techy, but sounds like some BS? How is it good for any modern computer controlled car to think engine temp is in the 160s all the time? In my mind that’s doing other harm, although obviously disabling the VCM which is the main point.

S-VCM and VCM Muzzler II claim they aren’t using a fixed resistor, that they have a logic and blah blah.

Are any of these VCM disablers legit? Would you use them on a new car? The advantage to S-VCM is it’s plug n play and could be removed in a matter of minutes for warranty work, but I don’t understand how it achieves its goal if it does (and doesn’t) skew the coolant temp readings all at the same time??

Just wondering if there’s any experts or anyone who understands this more that can shed some light. These guys on the Honda and Acura boards are just gung-ho “do it, add some Techron, and you’ll solve all your cars problems ever, even if it was burning 2 quarts per thousand miles, this will 100% fix it all”

 

[Hall]

One (or more) of the disablers are more than a simpler resistor that just tells the ECU what it needs to see in order to keep VCM from kicking in. My only experience is with the one made by a guy in Canada (I'll check my emails to see which it is). It's this one: https://www.svcmcontroller.com/

Someone will correct me, but I believe Honda has improved their VCM system over the years. Of course, some people don't care and just want it disabled 100%, so the market still exists. The guy I linked still makes them and indicates he has units that fit 2017 and newer models.

 

[Dave Sherman]

I put the S-VCM on my Pilot at 100,000 miles, though I will say other than the annoying shudder it didn't have the oil consumption issues. The active motor mounts still can (and do) wear out from trying to dampen the vibrations when cylinders are deactivated, so disabling VCM is not a bad thing. I had tried one of the fixed resistor disablers a while back, and while it did disable the VCM, it eventually triggered a CEL for apparently running too cold. The S-VCM is a bit better, it doesn't cause enough change to trigger a CEL, but enough to keep VCM inactive. The selling point of the S-VCM is if the engine actually does get well above normal, it deactivates so the gauge correctly shows that it's overheating.

All of the disablers skew the normal temperature reading so they fool the ECU into thinking the engine isn't up to operating temperature yet. The temperature gauge keys off that same sensor, and yes, even with the S-VCM I can see the temperature gauge is just a hair below normal.

I haven't had any issues with emission testing with the S-VCM, though at least one person on the Piloteers forum says it did cause an issue.

 

[t1snwrbrdr12]

One (or more) of the disablers are more than a simpler resistor that just tells the ECU what it needs to see in order to keep VCM from kicking in. My only experience is with the one made by a guy in Canada (I'll check my emails to see which it is). It's this one: https://www.svcmcontroller.com/

Someone will correct me, but I believe Honda has improved their VCM system over the years. Of course, some people don't care and just want it disabled 100%, so the market still exists. The guy I linked still makes them and indicates he has units that fit 2017 and newer models.

That’s one I was more interested in due to its simplicity and removal in case of warranty work. I guess I just don’t understand technology and electronics enough, I don’t see how it can fool it into a temp. to disable VCM but not report an inaccurate or skewed coolant temp at the same time.

 

[RooflessVW]

I have S-VCM on my '22 Odyssey.

It shows just under half on the gauge when at operating temp.

S-VCM is designed to lower the temp the ECU sees until there is an overheat condition then it shows actual, which is why I chose it.

 

[t1snwrbrdr12]

I put the S-VCM on my Pilot at 100,000 miles, though I will say other than the annoying shudder it didn't have the oil consumption issues. The active motor mounts still can (and do) wear out from trying to dampen the vibrations when cylinders are deactivated, so disabling VCM is not a bad thing. I had tried one of the fixed resistor disablers a while back, and while it did disable the VCM, it eventually triggered a CEL for apparently running too cold. The S-VCM is a bit better, it doesn't cause enough change to trigger a CEL, but enough to keep VCM inactive. The selling point of the S-VCM is if the engine actually does get well above normal, it deactivates so the gauge correctly shows that it's overheating.

All of the disablers skew the normal temperature reading so they fool the ECU into thinking the engine isn't up to operating temperature yet. The temperature gauge keys off that same sensor, and yes, even with the S-VCM I can see the temperature gauge is just a hair below normal.

I haven't had any issues with emission testing with the S-VCM, though at least one person on the Piloteers forum says it did cause an issue.

So you didn’t notice any issues with running conditions? No crazy increase in fuel consumption? Just what you’d expect from using all 6 cylinders all the time?

 

[Dave Sherman]

So you didn’t notice any issues with running conditions? No crazy increase in fuel consumption? Just what you’d expect from using all 6 cylinders all the time?

Nope. I haven't seen any noticeable change in gas mileage. Getting rid of the occasional VCM shudder is nice though.

 

[brages]

A new Honda would have VCM3 -- it's maybe a bit early to tell, but from what I read, VCM3 seems to not have the problems of the earlier generations. I would be hesitant to defeat VCM on a modern Honda.

I have a 2010 Odyssey (VCM2) and the S-VCM works well. The one that I had initially failed, and the seller sent me a new one.

 

[t1snwrbrdr12]

I have S-VCM on my '22 Odyssey.

It shows just under half on the gauge when at operating temp.

S-VCM is designed to lower the temp the ECU sees until there is an overheat condition then it shows actual, which is why I chose it.

Peak efficiency is dialed in for whatever the desired parameters (coolant temp included) are, which is why I have a hard time thinking that fooling the computer into seeing a skewed temp is good. Maybe it’s still in peak or closed loop range or whatever, just wish there were another way to disable VCM

 

[RooflessVW]

Nope. I haven't seen any noticeable change in gas mileage. Getting rid of the occasional VCM shudder is nice though.

My Odyssey also had a weird condition where the cruise would allow the car to slow to 2mph below the set point, then drop a gear and accelerate to 1mph above the set point.

S-VCM fixed it. I suspect that the car didn't have enough power to maintain speed in 8th or 9th with VCM active.

 

[Bill7]

I have 4 Honda Odyssey's with VCM.
I keep the VCM enabled on all of them for the fuel efficiency gains of running on 3 cylinders.
I drive with a light foot and I hypermile them by and maintaining momentum / coasting with foot on floor as much as possible.
I've been able to get 25 to 27 MPG on them doing rural and high way driving (I have scan gauge on each dash to monitor real time MPG).
My excel spreadsheet of gasoline purchases with mileages has verified the scan gauge MPG numbers.

VCM is very hard on the oil, with extreme engine temps over the front 3 cylinder heads which can cook the oil and turn it
into varnish or sludge.

With VCM enabled, it's important to use a short oil change interval.
See post #17 on this thread:

2014 Odyssey Sludge/Varnish

Did an oil change on our 14 odyssey tonight. It is closing in on 70k miles. It is my wife’s dd, so most use is extremely short drives, a mile or two at a time. We also use it for family trips of course. It has had the VCM disabled since maybe a thousand miles. These last two OCIs were Rotella...

bobistheoilguy.com

The OCI I use is: 4k miles/6 months which ever comes first with a good full synthetic 5W-30 (not 20 weight oil).

 

[JustN89]

I have the S-VCM installed on my RDX. As others have alluded to, the fact that it will override in case of overheating was the big selling point for me. No noticeable changes to MPG, either. I’d recommend them.

 

[parshisa]

I've been running S-VCM for the past 1.5yr or close to 15k miles on my '16 Pilot. Car drives a lot smoother (no weird downshifts when coasting), mpg hasn't changed at all. Doing a D&F every 10k, and running OEM ATF cooler.

 

[JHZR2]

Any Honda VCM disabling knowledgeable people here?

Likely buying a new Honda w/ v6 and VCM. I’ve never liked the idea of cylinders shutting down on anything. At least Honda doesn’t seem to have mechanical failures (lifters) that can still arise even if VCM is disabled. I know they clog up and get sticky piston rings, but if it’s disabled and well maintained I would think this is a non-issue.

My concern is all the VCM disables are simply skewing the coolant temp. I’ve tried to read up on it. Some claim they have a “processor” that tricks the coolant temp, but still relays the actual temp at the same time? I’m not techy, but sounds like some BS? How is it good for any modern computer controlled car to think engine temp is in the 160s all the time? In my mind that’s doing other harm, although obviously disabling the VCM which is the main point.

S-VCM and VCM Muzzler II claim they aren’t using a fixed resistor, that they have a logic and blah blah.

Are any of these VCM disablers legit? Would you use them on a new car? The advantage to S-VCM is it’s plug n play and could be removed in a matter of minutes for warranty work, but I don’t understand how it achieves its goal if it does (and doesn’t) skew the coolant temp readings all at the same time??

Just wondering if there’s any experts or anyone who understands this more that can shed some light. These guys on the Honda and Acura boards are just gung-ho “do it, add some Techron, and you’ll solve all your cars problems ever, even if it was burning 2 quarts per thousand miles, this will 100% fix it all”

I dont think your facts on the vcm muzzler is right.

The older one had a fixed resistor. It came with a couple for different weather conditions. The newer one has a variable resistor that you can adjust to your liking. In theory it could still turn eco/vcm on in some but not all cases then.

I’m not sure that a muzzler will solve issues. It may prevent them, for sure. It might even revert something if it isn’t too far gone. One issue I know happens is engine mount degradation. I suspect if one has bad mounts and then adds a muzzler, perhaps it will give some new life to them because the engine won’t shift due to going between deactivation levels.

Regarding the temperature sensor, as I recall there are two things:

1) I believe the vcm takes temperature from the gauge sensor, which is different from the ECU sensor. Thus the engine internal computations and operations are not affected.

2) I had read that the needle will be slightly offset. I’ll tell you this, I removed ours recently on a road trip. I do this maybe for a few hundred miles every 20k or so, so that the system can actuate and operate. I couldn’t really tell that the needle was in any different place.

That said, as related anecdotal evidence, I pulled the muzzler during a fuel stop when the engine was hot. It threw a CEL. I think the code was for a big change or reading below a certain resistance. So the ECU was watching it. And from the feel of driving it wouldn’t illuminate the eco light but would deactivate cylinders.

So that’s what I know. Good preventive maintenance, at a cost. I want to say we got 29.7 mpg average once it was enabled, while we got more like 25-26 with it off. I have nearly hit 30 with it disabled once under truly ideal conditions but it does make a difference even on the highway. But I keep ours disabled long term.

 

[I<3oil]

Mines working great, no difference in MPG. And yes, they're legit.

 

[t1snwrbrdr12]

[QUOTE="I Mines working great, no difference in MPG. And yes, they're legit.
[/QUOTE]
Which do you use?

 

[t1snwrbrdr12]

I dont think your facts on the vcm muzzler is right.

The older one had a fixed resistor. It came with a couple for different weather conditions. The newer one has a variable resistor that you can adjust to your liking. In theory it could still turn eco/vcm on in some but not all cases then.

I’m not sure that a muzzler will solve issues. It may prevent them, for sure. It might even revert something if it isn’t too far gone. One issue I know happens is engine mount degradation. I suspect if one has bad mounts and then adds a muzzler, perhaps it will give some new life to them because the engine won’t shift due to going between deactivation levels.

Regarding the temperature sensor, as I recall there are two things:

1) I believe the vcm takes temperature from the gauge sensor, which is different from the ECU sensor. Thus the engine internal computations and operations are not affected.

2) I had read that the needle will be slightly offset. I’ll tell you this, I removed ours recently on a road trip. I do this maybe for a few hundred miles every 20k or so, so that the system can actuate and operate. I couldn’t really tell that the needle was in any different place.

That said, as related anecdotal evidence, I pulled the muzzler during a fuel stop when the engine was hot. It threw a CEL. I think the code was for a big change or reading below a certain resistance. So the ECU was watching it. And from the feel of driving it wouldn’t illuminate the eco light but would deactivate cylinders.

So that’s what I know. Good preventive maintenance, at a cost. I want to say we got 29.7 mpg average once it was enabled, while we got more like 25-26 with it off. I have nearly hit 30 with it disabled once under truly ideal conditions but it does make a difference even on the highway. But I keep ours disabled long term.

I’m sure I’m wrong, I don’t pretend to know. Just trying to get a better sense of what’s really going on to make VCM inactive and how it’d affect other things. Thanks for the details, makes me feel a little better about them. I did read somewhere that there’s 2 coolant temp sensors, that the disabling device only piggybacks into and skews one of them.

 

[The Critic]

I really hope you're not planning to buy a first-year model, regardless of brand.

 

[t1snwrbrdr12]

I really hope you're not planning to buy a first-year model, regardless of brand.

Depends…. The DOHC Honda v6 has been out a year or two it seems. So in the case of the engine, it’s a little new for my liking. But this Palisade is a POS and ready to jump out of it asap. We will see. Nothings a done deal.

 

[UncleDave]

I have 4 Honda Odyssey's with VCM.
I keep the VCM enabled on all of them for the fuel efficiency gains of running on 3 cylinders.
I drive with a light foot and I hypermile them by and maintaining momentum / coasting with foot on floor as much as possible.
I've been able to get 25 to 27 MPG on them doing rural and high way driving (I have scan gauge on each dash to monitor real time MPG).
My excel spreadsheet of gasoline purchases with mileages has verified the scan gauge MPG numbers.

VCM is very hard on the oil, with extreme engine temps over the front 3 cylinder heads which can cook the oil and turn it
into varnish or sludge
With VCM enabled, it's important to use a short oil change interval.
See post #17 on this thread:

2014 Odyssey Sludge/Varnish

Did an oil change on our 14 odyssey tonight. It is closing in on 70k miles. It is my wife’s dd, so most use is extremely short drives, a mile or two at a time. We also use it for family trips of course. It has had the VCM disabled since maybe a thousand miles. These last two OCIs were Rotella...

bobistheoilguy.com

The OCI I use is: 4k miles/6 months which ever comes first with a good full synthetic 5W-30 (not 20 weight oil).

So you ignore the MM, and Hondas choice of oil grade altogether.

Curious, how is the VCM very hard on the oil when it only activates and extremely low loads?

How are these front 3 cylinders somehow hotter at 5-7% throttle at low speeds on flat ground, than they would be at 30-40% say climbing a hill in 100 degree weather?