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Switched from VCMuzzler to S-VCM

101K views 231 replies 60 participants last post by  Pedro Pozo 
#1 · (Edited)
I decided to take the plunge and switch from the tried-and-true VCMuzzler to the newer S-VCM. Having had the VCMuzzler on our van for over two years now, I feel as though I thoroughly understand how it works and what an owner can expect on a day-to-day basis from it.

I think it is important that I make one thing clear - I have absolutely no complaints about the functioning of the VCMuzzler. Even with the lowest resistance (blue) we only saw the ECO light on the dashboard a handful of times per year. I don't consider that a meaningful issue or a real cause for concern with respect to all the issues and symptoms regular VCM operation creates. The biggest reason for the switch is the fact that we anticipate that my wife will be making a few long trips this summer without me. And while she is an excellent driver and understands well what all the gauges in the instrument cluster are telling her and knows to monitor them all, I don't think I want her wondering about how far from the truth the temperature gauge is if the needle starts to crawl upwards. She knows about the VCMuzzler on our van and how it manipulates the ECU into thinking the engine coolant is cooler than it actually is.

I haven't seen a lot of pictures of the S-VCM being installed or how it looks in the engine bay, so I thought I'd snap a few pictures as I installed ours. First, here's what you get in the package:







You get the S-VCM controller and 4 little back zip ties to keep everything safe and tidy. It is a small little thing, designed to be only a little bit longer than the factory wiring harness lead to the ECT1 sensor.

Others have mentioned that the power lead to the battery is very small gauge, and they are right. This is the ring terminal at the end of the wire that gets connected to the positive battery post.



I removed both the engine cover and the front piece of the air intake to make it easier to reach both the ECT1 sensor and the positive battery post. The installation itself is quite straightforward and the instructions provided are good. If you follow them to the letter in terms of how to use the provided zip ties, the S-VCM is practically invisible when you look into the engine bay.

In this photo, the S-VCM is visible as a small grey rectangle underneath the wiring harness in the lower left corner of the picture. The black wire stretching across the middle of the picture is the power lead going to the battery (at this point it is not tied up, but just hanging loosely).



The remaining zip ties are used to secure the power wire to the positive battery cable and keep it out of the way. I found that using two of them was quite enough.



Once the installation is completed and the engine cover and air intake are replaced, here is what it looks like in my engine bay:



The S-VCM itself is hidden by the engine cover and the black power wire is very discreet. I believe it would take a well-trained eye to notice it.

For the time being, I am going to keep my VCMuzzler handy, just in case the S-VCM doesn't do what it claims or if the performance is not up to what I am expecting of it. The first drive this morning was just fine, which is what I expected. But I will periodically update this thread with my impressions and thoughts. I'm very much open to thoughts, questions, comments and discussion with my fellow Odyclubbers.
 
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#3 ·
I love the VCMuzzler but, here in Wisconsin the weather changes drastically all the time and I have to keep adjusting it so the ECO light doesn't come on. I still feel like people paid too much for the VCMuzzler. I don't feel like paying close to 100 for anotherome but, if this one works all year long with no adjustment, than I'm sold. Also, my VCMuzzler wasn't working properly for some reason from the beginning. 60-70% of my driving is highway. Sometimes it still comes on. I have noticed a huge difference especially in oil consumption. I haven't had to put any oil in yet which is rare. Usually I'm down a quart. Mine is an 07' by the way. Thanks for your post and pictures! I will have to buy this one for sure!

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#6 ·
I love the VCMuzzler but, here in Wisconsin the weather changes drastically all the time and I have to keep adjusting it so the ECO light doesn't come on. I still feel like people paid too much for the VCMuzzler. I don't feel like paying close to 100 for anotherome but, if this one works all year long with no adjustment, than I'm sold. Also, my VCMuzzler wasn't working properly for some reason from the beginning. 60-70% of my driving is highway. Sometimes it still comes on. I have noticed a huge difference especially in oil consumption. I haven't had to put any oil in yet which is rare. Usually I'm down a quart. Mine is an 07' by the way. Thanks for your post and pictures! I will have to buy this one for sure!
If you feel as though you have the VCM activating too frequently (even with the VCMuzzler), try a greater resistance. The blue resistor is the lowest resistance, followed by orange/brown and then red. That might give you a more satisfactory result.

There is nothing to adjust on the S-VCM - the controller is completely sealed and no user input from the outside is possible. You connect it to the ECT1 sensor, the van's wiring harness and the battery. That's all you can do with it. From there, the programming of the controller itself takes over and you get what you get.

We have not had VCM activate at all over the past two days and our van runs exactly as it did with the VCMuzzler installed (which is to say great). With that said, though, we have not done any driving that could be considered even remotely strenuous - it's been two days of puttering around town with very average ambient temperatures. Our first highway trip fully loaded is scheduled for this weekend, so I think that will be the first real test for us of how the S-VCM controller works under at least some strain. I will be paying close attention to the temperature gauge and whether it behaves any differently as we travel, especially as we get off the highway and re-enter an urban setting.
 
#4 ·
Another advantage of the S-VCM is that, should you want/need to enable VCM (say when gas tops $3/gal again ;) , or potentially for diagnostic purposes) temporarily, it is simplicity itself to wire in a switch for the B+ power wire. The S-VCM, when switched 'off' (power disconnected), returns the engine to designed (VCM enabled) function.
 
#5 ·
If anyone is having trouble seeing the pictures embedded in the first post, please have a look at the photo album "S-VCM Install" located in my profile. There are also a few extra pictures in there that I didn't use in the post.
 
#8 ·
Just want to note one thing incase some want to make the distinction. When the ECO light comes on, the engine is not always in VCM. It's just mean that it's being "economical."

But when VCM is on, it always equal to the ECO light being on.

This was true when VCM first came out on the Gen 3. I would think that's still true for the 4th Gen.

I get an ECO light on sometimes for a short while. Then it goes away. IMO, I don't think having the ECO light on at times is a big deal, as it does not mean the VCM is on. Even if VCM was on, it's for a very short while.
 
#9 ·
This is my understanding as well; the ECO indicator appearing in the instrument panel doesn't necessarily or automatically mean that VCM must be active. I don't know if there has ever been a definitive statement of all the criteria used to light the ECO indicator. If there has been, I don't think I'm aware of it. But I believe that for gen 4 Odysseys, the converse of that first statement is true - VCM never activates without the ECO light coming on as well. So the absence of the ECO light can be interpreted as the absence of VCM activation. Having VCM activate from time to time for a little while really isn't a big deal. In that respect, the resistor-based Muzzlers are perfectly fine. We only saw the ECO light a handful of times per year, and only in the summer. I won't stand here and pretend that's not good enough. It absolutely is.

For me, the major improvement S-VCM offers is a more realistic indication on the coolant temperature gauge while still suppressing VCM. That is what I am really after by making this switch. With a resistance-based Muzzler, there is no point in time at which the temperature gauge is showing a true reading (not that a coolant temperature gauge with no graduations or markings is especially accurate at the best of times, but still, the signal from ECT1 is always modified). When I first installed the VCMuzzler, I studied the temperature gauge and learned the "new normal" and feel very confident I could tell when the temperature was getting too high before anything bad happened. And truly, nothing bad ever did happen.

Like I said before, my wife knew about the Muzzler on our van and understands its purpose, but I don't think she is as closely attenuated to the behaviour of the temperature gauge as I am. I am not positive she would know that trouble was coming before it actually happened. I am hoping that the S-VCM controller will remove that potential hazard and keep her and the kids safer when they travel in the van without me.
 
#10 ·
I'm late to this thread and a newer 4th gen owner (and odyclub member). I have heard about some owners muzzling the eco boost, and wondering what the reasons are and/or detriments to just leaving it alone. I do notice more hesitation as it engages / disengages, and it is an interruption and a distraction more than anything. But is there a long term mechanical concern with leaving it be? I have not noticed any fluctuation in engine temp as was alluded to. If someone could quickly summarize the reasons for muzzling, I would appreciate it. Thanks all!
 
#12 ·
In a nut shell the long term mechanical concern is,, piston ring issues can developed leading to excessive oil in combustion chamber, which can screw with other thinks like plugs, cats...
 
#14 ·
An update after our first lengthy road trip this weekend:

The S-VCM definitely suppresses VCM activations very well - I never saw the ECO indicator even once during the whole trip. The coolant temperature gauge does behave a little bit differently than with the VCMuzzler.

Upon startup, I don't think the S-VCM does anything at all to the ECT1 signal. My impression is that the needle on the temperature gauge swung upwards more quickly than with the VCMuzzler, probably closer to what it did bone stock before I got the VCMuzzler. As the engine reached its normal operating temperature, the needle also swung a little bit higher, presumably because the S-VCM will let the gauge go all the way up to 166F. But after that, the needle stayed rock steady and the ECO light never came on.

I was especially interested what would happen when we got off the highway and re-entered the stop-and-go traffic of an urban setting. With the VCMuzzler, if it was hot enough and the traffic slow enough, we would sometimes get the ECO indicator coming on for a brief time. That did not happen this time around; the temperature gauge stayed exactly where it had been the entire time before reaching the city. It's impossible that the engine temperature did not go up at all, but it must not have reached the danger point where the S-VCM should turn itself off and let the temperature gauge shoot upwards to warn of a potential overheat condition.

I admit this impression-based commentary feels a little light and prone to confirmation bias ("He's already sunk money into the thing, so of course he's going to want to see it working the way he expects."). I think maybe over the summer I might reinstall the VCMuzzler and try to take some pictures or video of the temperature gauge in action, and then do the same with the S-VCM so that we can have a more objective basis for comparision. It would also be helpful to get some live data from an OBDII scanner, but I don't happen to own one of those right now. But for now at least, I am very pleased with the way the S-VCM controller works.
 
#15 ·
Is there a need to deactivate?

I have a 2016 Odyssey 6 speed. Cylinder deactivation on this vehicle engages and disengages imperceptibly - you can't feel it at all. No bumps, jerks or interruptions in smoothness that I can feel. Nada.

I have a vacuum gauge and a scan gauge on this vehicle, so I can see exactly when cylinders are deactivated and see the direct impact that deactivation has on mileage. The scan gauge reads instantaneous fuel mileage in tenths of a mpg, every second or so. It is easy to see when cylinder deactivation mode is operating. It is not so easy to see whether two or three cylinders are deactivated, but in time I have learned to see this too.

I have been using vacuum gauges on my vehicles since the early 80's. Vacuum gauges saved me gas by helping me to see the effect of small throttle movements - when I paid attention, that is. With the scan gauge and the vacuum gauge, I see that small throttle movements can significantly affect fuel mileage with little difference in vehicle acceleration. I have learned not to try and accelerate while going up hill, for example, and to speed up before reaching the bottom of a hill. And to lift off the throttle immediately when a traffic light changes to red. Depending on surrounding traffic.

When using the cruise control, cylinders remain deactivated longer than when using the throttle to control cylinder deactivation mode. The gas mileage while in cylinder deactivation mode is roughly 10% better when two are deactivated, and perhaps 15% better when three cylinders are deactivated.

No doubt that earlier years' cylinder deactivation have engagement and disengagement issues, so in this situation, deactivation is likely justified. But I can see no valid reason to disable cylinder deactivation on my vehicle. A dealer could argue that disabling cylinder deactivation would void the 5 year 60k factory powertrain warranty by disabling cylinder deactivation. If this is the case, one should attempt to get the dealer to either deactivate it or approve the fix beforehand. I also had a C7 Corvette stick shift with cylinder deactivation and that engaged and disengaged smoothly, but there was an increase in engine and power train vibration when it was active, that others found objectionable, but it could easily be turned off electronically. Nevertheless, these owners complained about it incessantly, but I could never figure out why.

I do see where it could possibly affect cylinder wear over hundreds of thousands of miles, but that is unlikely. Power output is in the low torque/power range when cylinder deactivation is in play, where combustion pressures are low - like around 10%-20% of available torque (and BMEP - Brake Mean Effective Pressure). Cylinder wear increases at high power and BMEP, not at low power and torque.

I had 248k on my 2000 Odyssey and was still getting 4500 - 5500 miles per quart of oil when a cow ran into this vehicle, totaling it. I might have gotten 6000 - 7000 miles per quart when it was new. I used synthetic Mobil One Extended Life oil for the last half of the vehicle's service life, often changing it near the recommended 15k change mark (after several conversations with Mobil engineers). Before that, 4000 miles was my change limit using several brands of conventional oil. In other words, cylinder wear over time was minimal with the 2000 Odyssey. If it was 2-3000 miles per quart, that would have been acceptable in an older vehicle with that mileage. And - the decrease in oil mileage could very well be the result of the hardening of the valve seals. Most manufacturers consider perhaps 1000 miles or thereabouts per quart acceptable on cars with remaining factory warranties. in other words, the ECO mode shouldn't cause a significant wear problem. Not to worry.

My complaint with cylinder deactivation is that keeping the engine in cylinder deactivation mode is touchy and very difficult to control with the throttle. In the range where deactivation comes into play, the throttle is overly sensitive. I wish I could fix THAT by altering the throttle curve in the deactivation and cruising range. I see very little increase in torque or acceleration in the last quarter of throttle movement, which seems wasted movement, to me. For years, throttle control has been designed by car manufacturers to cause the vehicle to accelerate strongly during the first quarter of throttle movement, making a vehicle seem and feel more powerful - but for me, that is no big deal.

If cylinder deactivation works smoothly and imperceptibly, as it does for me, I see no valid reason to arbitrarily disable it with aftermarket "fixes".

With my neighbor's 2014 Odyssey, 68k, deactivation is not smooth, according to him. I told him about the fix and he is considering it.
 
#198 ·
Is there a need to deactivate?

I have a 2016 Odyssey 6 speed. Cylinder deactivation on this vehicle engages and disengages imperceptibly - you can't feel it at all. No bumps, jerks or interruptions in smoothness that I can feel. Nada.

I have a vacuum gauge and a scan gauge on this vehicle, so I can see exactly when cylinders are deactivated and see the direct impact that deactivation has on mileage. The scan gauge reads instantaneous fuel mileage in tenths of a mpg, every second or so. It is easy to see when cylinder deactivation mode is operating. It is not so easy to see whether two or three cylinders are deactivated, but in time I have learned to see this too.

I have been using vacuum gauges on my vehicles since the early 80's. Vacuum gauges saved me gas by helping me to see the effect of small throttle movements - when I paid attention, that is. With the scan gauge and the vacuum gauge, I see that small throttle movements can significantly affect fuel mileage with little difference in vehicle acceleration. I have learned not to try and accelerate while going up hill, for example, and to speed up before reaching the bottom of a hill. And to lift off the throttle immediately when a traffic light changes to red. Depending on surrounding traffic.

When using the cruise control, cylinders remain deactivated longer than when using the throttle to control cylinder deactivation mode. The gas mileage while in cylinder deactivation mode is roughly 10% better when two are deactivated, and perhaps 15% better when three cylinders are deactivated.

No doubt that earlier years' cylinder deactivation have engagement and disengagement issues, so in this situation, deactivation is likely justified. But I can see no valid reason to disable cylinder deactivation on my vehicle. A dealer could argue that disabling cylinder deactivation would void the 5 year 60k factory powertrain warranty by disabling cylinder deactivation. If this is the case, one should attempt to get the dealer to either deactivate it or approve the fix beforehand. I also had a C7 Corvette stick shift with cylinder deactivation and that engaged and disengaged smoothly, but there was an increase in engine and power train vibration when it was active, that others found objectionable, but it could easily be turned off electronically. Nevertheless, these owners complained about it incessantly, but I could never figure out why.

I do see where it could possibly affect cylinder wear over hundreds of thousands of miles, but that is unlikely. Power output is in the low torque/power range when cylinder deactivation is in play, where combustion pressures are low - like around 10%-20% of available torque (and BMEP - Brake Mean Effective Pressure). Cylinder wear increases at high power and BMEP, not at low power and torque.

I had 248k on my 2000 Odyssey and was still getting 4500 - 5500 miles per quart of oil when a cow ran into this vehicle, totaling it. I might have gotten 6000 - 7000 miles per quart when it was new. I used synthetic Mobil One Extended Life oil for the last half of the vehicle's service life, often changing it near the recommended 15k change mark (after several conversations with Mobil engineers). Before that, 4000 miles was my change limit using several brands of conventional oil. In other words, cylinder wear over time was minimal with the 2000 Odyssey. If it was 2-3000 miles per quart, that would have been acceptable in an older vehicle with that mileage. And - the decrease in oil mileage could very well be the result of the hardening of the valve seals. Most manufacturers consider perhaps 1000 miles or thereabouts per quart acceptable on cars with remaining factory warranties. in other words, the ECO mode shouldn't cause a significant wear problem. Not to worry.

My complaint with cylinder deactivation is that keeping the engine in cylinder deactivation mode is touchy and very difficult to control with the throttle. In the range where deactivation comes into play, the throttle is overly sensitive. I wish I could fix THAT by altering the throttle curve in the deactivation and cruising range. I see very little increase in torque or acceleration in the last quarter of throttle movement, which seems wasted movement, to me. For years, throttle control has been designed by car manufacturers to cause the vehicle to accelerate strongly during the first quarter of throttle movement, making a vehicle seem and feel more powerful - but for me, that is no big deal.

If cylinder deactivation works smoothly and imperceptibly, as it does for me, I see no valid reason to arbitrarily disable it with aftermarket "fixes".

With my neighbor's 2014 Odyssey, 68k, deactivation is not smooth, according to him. I told him about the fix and he is considering it.
I have a 2016 odyssey with just under 100,000. Bought it 2 years old with 38,000 miles. Code popped for misfire on cylinder 1. Pulled the plug and it was all black and oily. Dealer wants almost 5,000 to rebuild the rings on pistons 1-3. I use synthetic oil every 5,000 miles. All maintenance is done on time. If I can spend 100$ to disable vcm to save 5,000, heck yea I’ll try it lol. And from what I’ve been reading, the 2016 wasn’t covered under the class action lawsuit for the extended warranty.. and it’s not covered under my extended warranty I bought either. Wtf. Might be time to dump it but I was hoping to have it longer than 4 years too..
 
#16 · (Edited)
Is there a NEED to deactivate VCM? "Need" is a very strong word, so the direct answer there is probably no. But the best answer is probably a little more nuanced than that.

It's really a case of different strokes for different folks - I hope the performance you're getting is now is what you will continue to get for as long as you own the van. Lots and lots of people do. But more than a few people don't, and this is for those who don't want fate or (mis)fortune to decide which group they'll fall into. Because it doesn't seem as though it's possible to know in advance whether or not you will have troubles. That's pretty much all it comes down to, at least until problems arise. The decision-making criteria change after being presented with a big repair bill. ?

There is no doubt that driving habits have a major impact on fuel consumption, regardless of any other technology. Being smart, efficient and proactive on the road is just good driving, and I'm totally with you on that.
 
#17 ·
It seems like one of the most popular threads on this forum are those concerning the Odyssey VCM and the installation of various after market VCMuzzler and S-VCM. Posters make it sound that if I don’t install one of these devices that an Odyssey engine is going to self destruct. To set the record straight my 2005 Odyssey EX-L was 13 years old and had 102,000 miles when I sold it. The only after market modification I made to that vehicle was the installation of a K&N Air filter which I cleaned every 20,000 – 30,000 miles. During those 13 years of ownership the only major problem I had with that Odyssey other than routine maintenance, and Tires and Brakes, was leak in the refrigerant line to the rear AC condenser. The engine never burnt any oil between oil changes, had any problem with spark plugs, motor mounts, or any of the other rather serious problems posters associate with the VCM system. As I remember my 2005 delivered between 18 to 24 Miles per gallon depending on where and how we drove it. I wonder if the Honda VCM system is so bad why after all of these generations of Odysseys does Honda still use the system?
 
#18 · (Edited)
It seems like one of the most popular threads on this forum are those concerning the Odyssey VCM and the installation of various after market VCMuzzler and S-VCM. Posters make it sound that if I don’t install one of these devices that an Odyssey engine is going to self destruct. To set the record straight my 2005 Odyssey EX-L was 13 years old and had 102,000 miles when I sold it. The only after market modification I made to that vehicle was the installation of a K&N Air filter which I cleaned every 20,000 – 30,000 miles. During those 13 years of ownership the only major problem I had with that Odyssey other than routine maintenance, and Tires and Brakes, was leak in the refrigerant line to the rear AC condenser. The engine never burnt any oil between oil changes, had any problem with spark plugs, motor mounts, or any of the other rather serious problems posters associate with the VCM system. As I remember my 2005 delivered between 18 to 24 Miles per gallon depending on where and how we drove it. I wonder if the Honda VCM system is so bad why after all of these generations of Odysseys does Honda still use the system?
With all due respect man, I have no interest in rehashing these tired conversations. They've been had a dozen times over in other threads - and in minute detail. I know no one feels like reading threads with thousands of posts in them, but if you really care to know the answers you'll put in the time.

The basic premise of this thread is that I (as a gen 4 Odyssey owner) have put in the time and effort to thoroughly research what VCM2 does and how it does it. I have researched, read, asked and studied far beyond this one forum, and I have reached the conclusion that disabling VCM2 is the correct choice for my family's vehicle. This means absolutely nothing for anyone outside my family. I'd encourage everyone else to do the same kind of research. Don't trust any one person or source exclusively, least of all me. No one out here on the interwebs knows me from Adam. Take anything I say or claim and test it against other sources of information. If you find me credible, test what others say against what I say.

Since I am operating here on the premise that VCM2 should be disabled, I am trying to convey how the different devices behave. I am not trying to convince anyone to do one thing or another - that's up to you. Your van, your choice. If you are having a great ownership experience without the use of a VCMuzzler or any of its counterparts, I'm happy for you. And you should definitely share that with the group because we need that balance of experiences - just do it in another thread.
 
#19 ·
Just bought a 2011 Touring Elite with 85k miles. The owner had never heard of this problem and never experienced any issues. Before I even took delivery I ordered a S-VCM because I hope to keep the van for a long while. My kids are 4.5, 1.5, and -.5. If my engine ends up not needing it then it was an insurance policy and I'm OK with that.
 
#20 ·
I suspect there may be two issues at play. 1) cylinder carbon 2) engine mount wear. I drive like you do, with a very steady foot on accelerator, trying to drive a steady speed, looking far ahead to minimize the energy lost to breaking. I never feel the VCM go in or out probably because I'm not asking for larger amounts of power. Now if I had more of a lead foot, accelerating quickly at lights, between cars, etc I can see the engine rocking when accelerating from a dead stop and each time the VCM goes in out out since this driving style would create a noticeable step increase or decrease in engine torque. This could increase the cycles on the engine mount creating accelerated wear on the engine mount, and early replacement. My odyssey only has 25K miles so its too early for either issue to be present. I don't have enough data to evaluate the cylinder carbon issue. There are all kinds of factors at play. Does the cylinder shut off cool those cylinders enough to affect combustion when turned back on? Are the rings adequate for the temps and pressures? I read Honda used the new rings for two years that lead to the class action lawsuit and an extended warranty for those years. Does the engine shut off lubrication to deactivated cylinders? Are cylinder walls over-cooled in deactivated cylinders? Are pistons over-cooled in deactivated cylinders? Is the deactivation complete keeping all fuel out of deactivated cylinders. I know that the new oils and engine tolerances are significantly better than 20 or 30 years ago. I have diesel engines at work that require special break in oil with reduced lubricating properties or they don't break in right. The new oils won't let the rings seat and bearings can take 500 hours to seat with new oils when they should be seated in the first 50 hours. The new oils are good and should protect the engines for hundreds of thousands of miles with regular changes. The new oils may lubricate well but they do not stop carbon build up in diesel engines. We've had diesel engines at work that spent 500 to 1000 hours at very low loads leading to low combustion chamber temperatures leading to wetstacking and stuck rings with excessive carbon build up. We've had to overhaul engines from wetstacking build up that wouldn't burn out under load. The engine problems described by various posters could be the result of carbon build up though I don't know the exact cause or failure mode if in the VCM system that would allow the carbon to build up in the cylinders.
 
#21 · (Edited)
You are correct; there are two different issues at play, both tied to VCM operation. The wear on the active engine mount is fairly straightforward - it's very difficult to get a V6 engine to run equally smoothly using 3 of 6, 4 of 6, or 6 of 6 cylinders, so Honda uses an electrically controlled active engine mount to help cancel the vibrations that naturally occur in 3 and 4 cylinder modes. That thing works very hard whenever VCM is active and I think it does an admirable job in most cases. But it simply wears out after a while; it is not a lifetime part. It is also a very expensive part that seems to nicely outlive the warranty so that owners are stuck with paying the hefty repair bill out-of-pocket.

The piston ring damage is harder to pin down, but here's where my current level of understanding is at: Lubrication to deactivated cylinders is not cut off, but fuel and spark are. Some oil is getting past the piston rings and collecting in the combustion chambers of deactivated cylinders. Why this does not seem to be an issue with the active cylinders is not totally clear to me, but the theory of a temperature difference between active and inactive cylinders affecting the way lubrication is managed seems plausible. When those cylinders are reactivated, that oil is being burned off in an incomplete combustion reaction which contributes to fouled spark plugs and carbon buildup. Eventually the plugs and buildup get bad enough that they begin to cause misfires which damages the pistons and rings further, the engine starts to burn more oil, and so the cycle perpetuates itself. Eventually the van runs so badly that the ECU starts throwing misfire codes on one or more cylinders and warning indicators light up the instrument panel like a Christmas tree.

3-cyl mode4-cyl mode6-cyl mode
Cylinder 1NYY
Cylinder 2NYY
Cylinder 3NNY
Cylinder 4YNY
Cylinder 5YYY
Cylinder 6YYY


The cylinders most prone to fouling and piston ring problems happen to be the same ones that are being turned on and off by VCM; that is, cylinders 1, 2, 3, and 4. Only cylinders 5 and 6 fire in all three operating modes of VCM2, and it is consistently cylinders 5 and 6 that do not have fouling and misfire problems. Conversely, it is so common for cylinders 1-4 to have these problems that they are the only ones which get repaired under the terms of the extended warranty Honda offered following that class-action lawsuit. Honda does not pay for new rings in cylinders 5 and 6 under the terms of the extended warranty.

So by deactivating VCM, what I am really doing with respect to the piston rings and spark plugs is ensuring that cylinders 1, 2, 3, and 4 are subjected to the same operating conditions as cylinders 5 and 6, which by all accounts (including Honda's) never seem to have any issues. And therefore my expectation is that while I might use a little more fuel over the lifetime of the van, I am not going to be faced with the potential of a partial engine rebuild and worn out pricey engine mounts. Honda's J35 engines that are not equipped with VCM (and especially VCM2) do not have problems with engine mounts and piston rings and fouled spark plugs and sudden excessive oil consumption. They are excellent engines that can run more or less forever. That's what I want. And so far, that is what I am getting; our van drives silky smooth, it's quiet, responsive, and never loses a drop of oil. When I did the last oil change, I got out more than 4.2 L out of a 4.3L capacity. If you consider that some oil is trapped inside the oil filter (and I spilled a bit getting the oil filter off :um:), that's pretty much all of it.

I don't know whether the piston rings are really the problem. It seems that Honda came up with new parts for the extended warranty program and for subsequent regular production, but there have been reports of people having these issues even in younger vans. More worryingly, there have also been reports of the problems resurfacing even after the extended warranty ring replacement. And part of the extended warranty deal is that Honda will only pay for the ring job once - if it has to be redone again in the future, the owner is on the hook for it.

Quite possibly the worst (or best) part of all of this is that there is no guarantee that any of this will happen to any given VCM2-equipped engine. It might not; but then again, it might. Lots of people have no issues (or practically no issues). There's no way to tell right up front whether you're in the lucky or unlucky group. But I believe that deactivating VCM changes the odds significantly in your favour.

I believe the complexity of the three-mode VCM2 and the problems that came with it are a major reason why Honda went back to a two-mode system (3 or 6 cylinders only) in the 2017+ gen 5 Odysseys. People with the current generation vans don't seem to be having these problems I think because the VCM3 system they have is a simpler design and better implemented.
 
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#23 ·
I am not try to stir the pot here but I believed the majorities of the Asian that owned the Odyssey don't even know they van equipped with VCM and they probably don't even know about the VCmuzzler either.
I do really love to hear from them in regard of the VCM issues.
Please excuse my English.
 
#25 ·
We have a 2012 we got with less than 3000 miles on it from a grandma who found it too big. I did all the oil changes myself with AMSoil Signature Series. But when I changed the Oil around 30,000 miles, I noticed it was very low. It was just after this when it threw the code for Spark Plug and missfire. Honda dealer did a ring job on 3 of the cylinders under warranty. I paid to have the last 2 spark plugs changed so they all had new. That's when I got the Muzzler and have kept it on since about 30k miles. At 80,000 now it doesn't use oil with 7000 to 8000 miles between changes.

VCM does cause oil consumption no matter what even if you don't have issues. Rings are supposed to move some but I think the lack of pressure on the pistons lets the oil gaps align and the oil blow by causes them to stick there compounding the problem on the J35Z8 engine. If you look at the 2017 and newer J35Y6 on the 2016+ Pilot and 2018+ Odyssey you will see that they keep the Spark plug firing to try and burn off the oil that bypasses when cylinders deactivate.

Last year, we got a 2017 Pilot and I put the VCMtuner on from the beginning after my experience with the Odyssey piston rings. I wanted to bring the engine in right. The tuner is more adjustable than the resister but otherwise functions the same. I'd be interest to try this S-VCM. It would be great if someone could design something like the S-VCM that could output the true temp along with the adjusted temp via Bluetooth or something.
 
#26 ·
*** Update ***

We just came home from a 1,600 km (1,000 miles) round trip holiday from Calgary to the Okanagan Valley in BC. Temperatures ranged from from about 26C to 41C (79F to 106F) and included a trip through Rogers Pass (elevation of 1330 m/ 4360 feet). Never saw the ECO light once, though the cooling fans were running full-on the overwhelming majority of the time. The temperature gauge did creep up well past the halfway mark when we got stopped by highway construction when it was about 36C outside, but I don't think we were ever in an overheat condition where the S-VCM would turn itself off. Because we were stopped and VCM doesn't activate regardless of other conditions when you aren't moving, I'm not completely sure whether the S-VCM controller ever switched itself off. I never saw the temperature gauge go to a dangerously high level, so we were probably safe enough the whole time. I left the engine running during the stoppages to make sure that the water pump kept the engine coolant circulating, as hot as it was.

Our fuel economy still hovered in the 28-29 mpg range over the highway portions of the trip without much care or effort. So far, it seems like the S-VCM is full value as advertised.
 
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#28 ·
You're welcome! :)

Thank you for the feedback - making it easier for others is exactly what I wanted to achieve with this thread. Everyone who has contributed has increased my knowledge and level of understanding too, and I appreciate it.
 
#29 ·
There are so many threads on the VCM topic I am not sure if proper etiquette is to post my question/comment here or to make a new thread. I will post it here and let moderators tell me.

I have a new to me 2015 Odyssey LX. I installed the SVCM last night. I was having driveability issues with VCM. Mainly when cruising at highways speeds and constantly varying cruise control speeds and the annoying drone noise. It was so bad my wife even complained, and that is saying a lot. I have a scanguage II so I am able to watch actual water temps. Before the SVCM install the temp was locked in at 176F. After the install temps are running 161F. Even before knowing how the SVCM and VCMuzzler systems worked I was thinking 176F was a bit cool for engine temps.

I wanted to install a higher temp thermostat to increase heat output and shorten cab warm up times. I have 4 small kids and want them to stay warm and not have to put on super thick coats as they are unsafe in car seats. My realization is this: Since I chose the SVCM I cannot change to a higher temp thermostat and have the VCM deactivated. I live in Minnesota. We are often below 0F. Sometimes for weeks at a time. I have read on other threads that the heat output at 176F vs say 195F coolant teamperature is quite noticeable.

I could have gone with a VCM Muzzler and used a higher resister to show that my 195F water is <165F to the VCM... but I went with SVCM and now I am stuck not being able to use a higher temp. thermostat.. Anyways, I am combining a couple of different topics in my comment but just wanted to let you guys in the cold climate have another thing to think about before choosing between SVCM and VCMuzzler.

My solution is going to be a car starter which was on the top of the priority list anyway. I am going to skip the higher temp thermostat.
 
#30 ·
My realization is this: Since I chose the SVCM I cannot change to a higher temp thermostat and have the VCM deactivated.
How have you arrived at this conclusion? I don't think I see how changing the thermostat affects what S-VCM does.

The S-VCM is supposed to receive the true coolant temperature from the ECT1 sensor as its input data and respond to whatever it reads. The fact that your coolant might be hotter to start with simply means that S-VCM's adjustment of the output signal would be greater (to keep the reported temperature below VCM's activation threshold), but that doesn't affect the actual coolant temperature or how your heater works.
 
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#32 ·
This is all very interesting. Thank you for the write-up. I’m new to VCM suppressors and only became aware of them from your very valuable comment in my other thread.


A few questions come to mind:


Instead of the simple resistive VCMuzzler, why not solder a resistor to the ECT#1 line, or perhaps even a small potentiometer instead of paying all that money for a resistor and a couple of connectors? With the potentiometer one could also tweak the resistance until they get the desired behavior.


For the temperature gauge, wouldn’t it be enough to derive the new temperature scale (would essentially be a compressed scale on the hot end)? I suppose one could even open the instrument panel and tape the new scale on the temperature gauge.


I imagine that with the S-VCM you would still see some compressed temperature readings on your instrument panel -- except when the S-VCM detects its pre-programmed overheat value (I wonder what that value is ) at which point it would let the true resistance through and you would see a sudden jump in the temperature gauge?


I would gladly put some sort of VCM suppression device on my 2012 Odyssey. However I’m concerned that a chronically suppressed temperature reading to the ECU may have other unintended consequences. For example alteration of fuel trims, more O2 or unburned fuel ending up in the catalytic converter and thus perhaps a shortened cat life, just to mention one.


Is there a way to capture the VCM activation output signal from the ECU on the OBD2 port? That would answer the correlation between VCM and ECO indicator on the dashboard.
 
#33 · (Edited)
All asked, answered and discussed ad nauseum in numerous other threads.

Variable resistor: Already done and can be bought with the MaxMuzzler and the VCMTuner.

Unintended consequences: None-other than you might get an occasional check engine light for a P0128 if you're suppressing the temp too much--that's why there are numerous different resistors or the variable resistor.

VCM activation can't be captured and disabled via the OBDII port.

Soldered in resistor: Yes, you can do that if you like your wiring harness hacked up and have no intentions of removing said soldered in resistor. You also open yourself up for corrosion or other damage to the harness, especially for those who live in salty road environments. Having a completely reversible method that can be installed in less than 60 seconds is not a bad deal for $100. S-VCM takes a few more minutes and does a bit more but similar end result and is reversible.
 
#35 ·
Not to worry se88GGnka - the information available on Odyclub alone is truly extensive; the number of posts dedicated to figuring out how best to deal with VCM number (without exaggeration) in the thousands. And then when you combine that with the bank of knowledge built up parallel to us here by people on the Accord, Ridgeline, Pilot and Acura forums, we're into the tens of thousands. VCM has given a lot of people a lot of pause over the years, and it has been years that people have been working on the various solutions that exist today.

The biggest advantage to the pre-made solutions is the ease of installation and removal; these devices are absolutely not endorsed by Honda at the corporate level and being able to easily remove them without a trace before going to the dealer for service or warranty work is really nice. Also, a cut wiring harness is an immediate red flag for a lot of people when it comes time for resale. A knowledgeable observer can tell if the wiring has been cut, no matter how good a job the person doing the cutting did. There are also some service procedures that require an unaltered signal on ECT1 to be completed properly, so the soldered-in approach isn't the best one. The popular resistance-based options like VCMuzzler and MaxMuzzler are very high quality pieces that have been shown to be dead reliable by thousands of users over (probably) millions of miles driven. S-VCM is a newer technology but it is also proving to be an excellent choice thus far.

I'm trying to keep this thread focused on S-VCM as much as possible, but the other options are truly excellent and they're well-documented in other threads.

You strike me as the type who would indulge in reading through at least some of the more comprehensive threads on mitigating VCM, and I would totally encourage that. I think it's interesting to watch the research and learning unfold as you read about how concerned owners (with no factory support) were stepping up to help each other protect their investments.
 
#37 ·
But I much prefer accurate Temperature readings, which the S-VCM provides. Especially important when pulling a trailer.

Switched out from the VCMuzzler to the S-VCM two weeks ago. No problems with the VCMuzzler during the time it was on the vehicle. It did what it was suppose to do.
 
#38 ·
Seems like the S-VCM would work, however I'm skeptical that it will report accurate temperature when the engine is at normal operating temperature range.

My hunch is that the S-VCM's digital logic, initially, while the engine is warming up, is reporting to the ECM the exact same resistance (i.e. temperature) that it reads from the sensor. There is no reason to fake the resistance/temperature in this engine warmup phase.

However once the engine approaches normal operating temperature and the resistance the S-VCM is reading from the sensor drops below that magical VCM trigger resistance (allegedly corresponding to 167 degrees whatever that resistance is) then the S-VCM starts reporting to the ECM a constant resistance corresponding to 167 degrees (probably a little lower since the S-VCM designer would have left some safety margin, say 164 degrees(?), and that assumes all ECMs are programmed the same and don't have some sort of "sensor learning mode").

Now the S-VCM's more useful digital innovation seems to be that once it starts seeing at the sensor a resistance low enough to indicate tendency towards overheating, say 205 degrees or something like that (?) then it overrides its resistor faking logic and let's the true (low) resistance reading through to the ECM which can then take the appropriate actions, including alerting the driver to overheating on the temperature gauge.

So what does the driver see?

According to this theory,
while the engine is warming up the driver sees the actual true engine temperature on the gauge (temperature rising fast). Then when the temperature reaches the roughly 167 VCM point the driver sees the temperature gauge plateau at some lower point (similar to VCMuzzler) and that is what most drivers will see most of the time throughout their trips. Now, if the engine gets closer to the overheat temperature (whatever temperature the S-VCM's designer decided) the device will let the true temperature through to the ECM and the driver will see a sudden jump in the gauge towards the overheat range.

Now, this is all pure speculation on my part, so sorry if it proves to be completely off basis. Perhaps those of you having/testing the device can provide actual observational data to confirm or disprove this theory.

There could also be variations, depending on how sophisticated the S-VCM designer decided to be. So, for example, the designer could have decided on a smoother transition to overheat readings as not to stun the ECM which might then throw a sensor code, though throwing a code in an approaching overheat condition may not be that undesirable.

The problem I see is that in order to prove or disprove one would have to experiment with engine overheating conditions which is hard and perhaps also undesirable to do.
 
#39 ·
Especially considering that, since I have been on the Odyclub since 2003, I only remember one overheating Odyssey. It was very high mileage with a plugged up radiator. In fact since 1978 I have had 8 Honda’s and barely had one even show a raised level on the guage. The guage is still going to show that the vehicle is overheating, it’s just going to show it the width of the needle lower.
 
#40 ·
Well, with the resistor the difference is one needle width but that is ONLY at normal operating temperature. I bet that in the overheat range the difference becomes ever wider with rising temperature. This is because as the temperature rises and the sensor resistance decreases (non linearly) the fixed 82ohm resistor (or whatever you are using) that is in series represents an ever bigger (additional) proportion of the sensor resistance.

Seems like the S-VCM gets around that problem by masking true temperature (and display) only in the normal temperature range.

Actually, I take back that it will be difficult to test the S-VCM behavior. Yes it will be difficult to test on the van, but one could just take out the S-VCM and measure the output resistance (reported to ECM) vs the input resistance (read from sensor). Then assuming that one has the resistance vs temperature graph for the Honda sensor one could reliably predict the behavior of temp displayed on the dashboard gauge vs true engine temperature.


For that matter one could just take out the Honda temp sensor and derive that temp vs resistance relationship up to about 212F using a pot of water on the stove. Or just take the entire sensor plus S-VCM put the sensor in water, power the S-VCM with 12V, gradually heat the water with thermometer and derive both curves at once: temperature vs sensor resistance vs S-VCM reported output resistance. From that graph one could readily derive the true vs reported (i.e. seen on dashboard) temperature. To extend the graph a little above 212 one would have to use dry heat. I suspect though that at 212 and above the S-VCM reports the resistance exactly as it reads it from the sensor(?)
 
#41 · (Edited)
I think you pretty much have it figured out, but I also think you might be asking too much of the temperature gauge in the instrument cluster. There is a limit to the precision one may expect of the information gleaned from a gauge with no scale or graduations. At a normal operating temperature range, the only thing the gauge is good for is to tell you that you're at a normal operating temperature range. I doubt if the difference between 164F and 167F is clearly discernable on the gauge, even on a stock setup.

If you really wanted to push the research envelope on this, you could use a 50/50 coolant mix instead of water on the stove; your boiling point would go up to about 223F. And the static boiling point of the coolant mix goes up by about 3F for every 1 psi of pressure in the cooling system [LINK], so if we presume about 15 psi in the average automotive cooling system, that would take us up to about 268F before a boil over happens. Got an old pressure cooker handy?

I am guessing that you possess above-average Googling skills, but if you haven't seen the S-VCM website [LINK], they describe nearly all of what you're thinking about there. At an actual 210F, S-VCM reports <167F. By the time the actual temperature reaches 230F, S-VCM is outputting an unmodified signal. I doubt there is some kind of smoothing algorithm to make the temperature increase gradual as you approach an overheat condition - if you are about to overheat, you need to know RFN. I would expect the needle on the gauge to suddenly jump at the moment S-VCM turned itself off. Potentially throwing a code for a sudden drastic temperature increase would be a minor consideration, in my opinion, given the severity of an overheated engine.
 
#42 ·
Thanks for the link.

Indeed the temperature vs resistance table on the site does not tell the whole story of what happens between 210F and 230F. But an abrupt unmasking of the real ECT and potentially a CEL may even be desirable in overheat? -- two indications of trouble rather than one. Or does the ECM throw an overheat code anyway?

BTW, I think an even better way to disable VCM would be for someone to modify an OBD2 app to monitor for codes, making an exception specifically for the code associated with the VCM pressure sensors. Then we could just disconnect the VCM oil pressure sensors, buy a cheap $30 android phone on EBay and a cheap $10 ELM327, tape the dashboard CEL and use the phone and app as a new surrogate Check Engine Light. The app could even be programmed to say things like "Hey dude you have a new code [other than the VCM oil pressure code]".

Then, presumably, there would be no temperature faking at all, presumably just VCM suppression.
 
#43 ·
Then we could just disconnect the VCM oil pressure sensors, buy a cheap $30 android phone on EBay and a cheap $10 ELM327, tape the dashboard CEL and use the phone and app as a new surrogate Check Engine Light.
It would be nice if VCM suppression could be done easily through the OBDII port, but tape on the instrument panel and extra boxes all over the place? That would just junk up my pristine interior (of which I feel I am justifiably proud). As it is, S-VCM tells the PCM little white lies as long as it's safe to do so, and as soon as it isn't safe anymore, it hits you with the unvarnished truth. And it is (for all intents and purposes) virtually imperceptible - invisible from inside the van, nearly invisible under the hood, and the van drives as everyone expects that it should. I'm willing to call that good enough.
 
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