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Discussion Starter #1
Hello there,

First of all, I'd like to say that I'm not an Ody owner, I own a Pilot. I, like many other Pilot owners had problems with VCM causing vibrations when activated particularly during cold weather. Not knowing what VCM was or what it was all about, I took to my computer to learn all about it and decided very quickly that it is flawed technology, leading to grief for many including oil bypassing and excessive consumption, misfire, plug fouling, vibrations issues and potentially long term engine damage. I also found out quickly that there is no good way to disable it without causing CEL codes and disabling of other systems when removing the connector on the oil pressure switch.

Because I believe Honda only created VCM to improve it's fuel efficiency ratings, and meet CAFE regulations and sell more cars, I set out to come up with a better way to disable it. VCM isn't good for an engine. Both Honda and GM have proven that now. Their PCM flashes and component swaps, extended warranties and TSB's all prove that out.

So I believe I've solved this for those that want to disable it. I've come up with a solution that isn't through programming as nobody has figured that out yet, but I've used it for about 2-3 months now and I love it. My Pilot runs like a dream and I love having no VCM activate. the drop in Mileage is minimal. Others urged me to spread the word specifically to the Ody forums because there are many Ody owners that are unsatisfied with this technology also that honda has forced upon us. My searches here have confirmed that to be true.

My solution creates no CEL codes and can be installed in a about a minute and can be reverted to stock in the same amount of time for those times when you want to take it to the dealership.

I've checked with the moderators and they seem to be open to me posting this in the classifieds section, but I just want to make 100% sure before I do. It's been a popular fix so far and I want to help others rid themselves of VCM. Engines aren't meant to drop cylinders, nobody has been able to do it without issues yet. Having said that, I'm not saying that VCM always causes problems. The majority of owners are either not sensitive enough to it's side effects, or their vehicles don't ever experience any issues. However, there are plenty of others that are.

This has all been discussed over and over in many forums so I don't want this to be another divided debate on whether VCM is good or bad, I'm just offering up my solution to those who hate it like I do. I was seriously considering selling my Pilot, but now I love it.
 

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Reminds me of those infomercials that talks about something they claim works, but they never tell you what it is.

Just place 1 ad in 1 paper and you will be filthy, stinking rich. :D
 

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Sounds too good to be true. Can you explain what it is, and how it works? I doubt anyone is going to buy a magic bullet solution/something from a strange person on the internet with no explanation other than "it works awesome".
 

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I am originally from Missouri, the "Show Me" state. So show me.

An active CEL is the only thing my solution lacks. And I have over 20K of flawless performance history to back it up.
 

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If you read some of his other threads on other forums, he is basically adding a in line resistor between one of the engine coolant sensors and the ECU, which causes the temp reading to drop a few degrees to the ECU. As a result the VCM never gets the temp reading it needs to kick in. Its not a big drop in temp, so there should not be other ramifications. I think it will work effectively and will probably buy one when I replace my 2003 with one in this gen. Seems like there are tons of EX-Ls and not many EX's. Touring is out for me and so is LX.

Congrats Verbatim.
 

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I think one drawback of that strategy may be the ECU will interpret the lower coolant temperature as a lukewarm engine and consequently enrich the air fuel mixture to the detriment of fuel economy. If it's cold enough to disable VCM, it will probably enrich the mixture. Time will tell. In the interim, I can live with the CEL.
 

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Discussion Starter #8
Relax folks I'm not hiding anything. A resistor inline with the ECT1 circuit fools the PCM into thinking the engine hasn't reaches operating temp so VCM never engages. The actual operating temp of the engine is unaffected because it's controlled by the thermostat and the cooling fans. The cooling fans still kick on because ECT2 is unaffected and turns them ok. A/f ratio seems unchanged as this is controlled by other sensors and IAT plays the role for that when it comes to temperature. I've ran it for months now and no indication of running rich or lean, just smooth driving with no annoying dash lights (CEL or ECO).

not everyone is going to agree but my experience and others with this mod has been great so far.

The only downside is that your indicated engine temp is about 15 degrees lower so if in the unlikely event that your engine overheats, it will be fifteen degrees hotter when the warning comes on. However if you note the new normal operating temp as just slightly below what it was and monitor it like you should then you won't have an issue.

I'm doing this mainly to help others out. Take it or leave it, my main goal was to disable it for myself first.

More than happy to answer any and all questions.
 

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Along those same lines, is there a sort of time limit before VCM is enabled after all other conditions are met?
eg. Say all other conditions are met for VCM to be enabled, maybe there's a 60 seconds timer that kicks in before VCM is actually available to be activated?
If that would somehow be the case, I can easily see a circuit which would switch that resistor in for a second or two every 60 seconds. PCM sees normal temps for the bulk of the time, but the VCM never gets enabled due to the time-out.
 

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Discussion Starter #11
Along those same lines, is there a sort of time limit before VCM is enabled after all other conditions are met?
eg. Say all other conditions are met for VCM to be enabled, maybe there's a 60 seconds timer that kicks in before VCM is actually available to be activated?
If that would somehow be the case, I can easily see a circuit which would switch that resistor in for a second or two every 60 seconds. PCM sees normal temps for the bulk of the time, but the VCM never gets enabled due to the time-out.
I haven't been able to detect anything like what you describe. VCM seems to activate instantaneously when the Engine Coolant Temperature as reported by ECT1 reaches 167 degrees. Once it is active, it doesn't stop activating (under the appropriate conditions of course) until the temperature drops back down to about 162-163 degrees. I'm not saying there isn't some sort of time lapse, I just haven't been able to detect one and I'm not sure what the purpose of a time delay would be in the algorithm if all other conditions are properly met.
 

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Discussion Starter #12
I'd be interested - if its just a simple resistor, why not try it? I'm hoping the fix is the same on the 4th gen engine
I've consulted the parts finder for various models of Honda and Acura vehicles. PCM's for different models, and even different years of the same model are often different, but I believe the programming for when VCM engages would be the same for all. So for other compatibility, I looked at valve rocker arm assembly to see if the VCM components are the same and I also looked at ECT1. If the components were all the same, I felt that I could group those makes and models together as ones that would benefit from the same fix. What I discovered for the Odyssey is that the 2008-2015 engines all use the same components, so I believe it would work for the 4th Gen engine. It seems that in 2007 and prior engines, the VCM components were slightly different. In the 2005 and 2006 models, they used an older model ECT1 with a different connector type.

Long story short, I believe the harness I have developed will work just fine for 2008-2015 Odyssey. It may work for 2007 if the PCM programming is the same for that model of VCM engine (very likely). It won't work for 2005 and 2006 models because the ECT connectors are a different type. I could make a harness with the older connectors to try on an older engine and it's VCM system, but I don't have a vehicle to test it on.
 

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Discussion Starter #13
I think one drawback of that strategy may be the ECU will interpret the lower coolant temperature as a lukewarm engine and consequently enrich the air fuel mixture to the detriment of fuel economy. If it's cold enough to disable VCM, it will probably enrich the mixture. Time will tell. In the interim, I can live with the CEL.
One of the main reasons I pursued this was that when I pulled the pressure switch connector, like many now do, it for some reason disabled other systems in my pilot, the most disturbing of which to me was VTM-4, or the 4WD system. It turned my pilot into a 2WD vehicle and in my climate, that was bad. My traction while driving in the winter was terrible compared to what it was, so I couldn't live with that. While on the odyssey, that's not an issue, seems that for many, when they pull the connector, it also disables the VSA system, which I also would not want to disable. Additionally, running for extended periods with codes recorded in the ECU could give your dealer grounds for voiding your warranty because you did not bring your vehicle in for service when there were CEL codes visible. I'm not saying they would do that, but some dealers will use any excuse to try to void a warranty claim.

As I mentioned in another post, I do not believe the ECU uses coolant temperature to determine much in regards to the A/F ratio. The IAT, MAP and O2 sensors etc. take care of that for the most part. I have not noticed any evidence of running rich. The amount of fuel economy that I've seen dropped is about 1 MPG, which if you look at Honda's numbers for fuel efficiency with and without VCM, appears to be just about exactly what you'd expect to lose.
 

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@ verbatim:

I like the concept. If it works as you claim, it would be a cleaner fix and no CEL. I wanted no VCM and was willing to live with the CEL. My mileage drop was less than yours when I deactivated it.

However, I would want to run the VCM periodically to keep it limber and operational in case I decided to sell the vehicle. I would not be want to take less for the vehicle because VCM was inoperative.

What is the degree of difficulty and time required to install and un-install?

I am nobody's electronic guru but curious how you arrived at which resistor to install in the line? I would not know where to start.
 

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Discussion Starter #16 (Edited)
I bought a OBD II diagnostics tool that transmits the ECU sensor readings wirelessly to my smartphone. Among everything else, it transmits the ECT1 reading, which I monitored to find the actual temperature that VCM kicks in at. Then, I went online and researched Honda's ECT sensors and how they work. What resistance range is typical for those temperatures and then bought a potentiometer in the range I needed, put it in the circuit and kept playing with the added resistance for a while until I reached what I feel is the right amount by monitoring the new temps with the OBD tool. Took some time and different outside temperatures to come to the final value.

As far as the installation time, that's the beauty of it. It takes literally less than a minute to do in either direction. If you want to revert back to stock, it takes the same amount of time. No cutting into wires, nothing. You unplug the connector from ECT1, take my harness and plug it into the connector you just unpluged. the other end plugs into ECT1. That's it. You might want to take the engine cover off for easier access, but it's not necessary. that would add about another two minutes to the process. I went through the effort to make it completely sealed and uses the OEM connectors that took me a while to find, and the tools necessary to properly make up the terminals and seals within those connectors.

Price? Well, I'm going to take the chance and post it to the classifieds now. I got what I think is approval from the moderator, but I was just really leary about posting due to the very strongly worded warnings in the classified stickies. I've not reached 20 posts yet or been here six months, but I am not here to just peddle my wares, I'm here to try to help people with this, at the urging of others. I plan on staying around here and discussing this and other issues that I feel I can weigh in on as I am a self proclaimed "techie" lol.
 

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I'd sure like to try your fix on my 2006 EX-L. What would it take to test it and more importantly, what could go wrong if it didn't work correctly?
 

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Discussion Starter #18
I'd sure like to try your fix on my 2006 EX-L. What would it take to test it and more importantly, what could go wrong if it didn't work correctly?
Well, my harness won't work on an '06 because for earlier years, honda used a different ECT sensor connector. It's similar but my harness won't plug in to your connectors.

I haven't tested older models at all. the VCM components are slightly different in your engine than the newer generation VCM. However, I believe Honda would have used the same logic to not engage VCM until the engine is up to operating temperature. I believe they do this because they know full well that deactivating cylinders can cause bad things at times, and doing so when the cylinders are cold and not properly lubricated would be even worse. therefore, I feel the ECU programming would be very similar and so there's a very good chance that it would work for yours as well.

I also think the risk of trying it out is small. The best thing to do would be to buy the OBD tool like I did and monitor engine temp before and after the mod and compare. If you just see a shift of about 15 degrees or so and nothing else seems to be affected, except VCM doesn't engage then you're good to go. If it throws codes, the temperature shift isn't what you'd expect, or you notice anything else that doesn't seem right, then it might not work for you, but it's highly unlikely that this would cause any permanent damage to anything.

I have been asked this before by other owners of older vehicles and so I'm willing to purchase some connectors for your vehicles and make up some harnesses for people to try. It would be good to offer everyone the same opportunity to disable VCM. If you want to help out, locate ECT1, remove the connector and post a close up picture of it for me. I'm pretty sure I know which one it is, but Sumitomo made two slightly different connectors for those older vehicles and I'm not quite sure which it is. I'd have to go to the pick and pull to be sure but if you could post a pic it would save me a trip.
 

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I'll give it a shot but it might be a few days based in my work schedule. Still snowing where I am so it sure won't be tonight. Snow on Easter Sunday...there oughta be a law.
 

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To clarify, you asked if you could post information about VCM. We never did discuss any sales related postings in the classified section. You can post your for sale post after you meet the rather easy for sale/trade terms. I deleted your new thread there as it does not yet comply with the policies/terms.
 
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