Hey guys, recently picked up a '16 RDX base model. 90k on the odometer. One owner, literally every service record since bought new at the same acura dealer.

Though it's been well taken care of, I'm eager to start wrenching on this one. First and foremost, the VCM bypass.

Just wondering, if anyone here has the custom version of S-VCM, if it's worth it? It seems like the standard version will do the job, but I'm not sure if having an on/off switch is as beneficial as it sounds.

Thanks for any input!

 

2013RDX AWD, mileage 170K miles. The engine runs like clock, oil consumption is 0. Please do not break the car, do not install any bypasses.

 

I have the same train of thought myself. I like to keep everything stock.

 

2016 Advance model - 0 issues. To OP it's your vehicle and you can do as you like but really no need for VCM control.

 

So after some further research, it appears that the class action lawsuits and well-documented issues of many Honda V6 engines with VCM seemed to cease in the year 2012 across all of the models. My worries of plug fouling and oil burning are gone.

However, there still exists the less-than-ideal feel of the transmission with VCM. Not to mention the service bulletins for the torque converter shudder. I'm sure the engine mounts have loved experiencing that over the life of this car. It's looking like a software update for the trans and disabling the VCM has improved many users driving experience on this website.

Ultimately, manually closing the valves on a moving piston is not how a v6 engine was designed to run. I get that active engine mounts exist but the vibration and feedback through my transmission and car in general is enough to make me want a smoother experience. And I guess that's all it comes down to. I don't care about a 1-2mpg difference. I care about the engine running smooth across its power curve.

 

Your words make sense, but then the correct decision is to reflash the ECU so that the software car will forget about the VCM, and not hammer the crutch by cheating the temperature.

 

I suppose that's reasonable. In all honesty, I am probably going to buy it either way and do some testing. In the event that the difference with/without the VCM on the rdx is negligible, my parents have an '08 Odyssey as an extra car that is in definite need of one, with the plug fouling and all. I'll be sure to report my findings when I can.

 

Hey SauceBoss, any update on your experience with VCM de-activation?

 

Hey, thanks for checking in! As it turns out, the transmission software in this vehicle had not been updated - and once that update had been performed, there was a night and day difference in the driving experience. What I thought were issues with the VCM, actually turned out to be issues with the transmission. I performed fluid changes, three out of the five pressure switch replacements, and changed the inline filter - and the dealer did the software update. It eliminated any questionable shudders, jerks, etc. when driving.

The driving experience is great. And per what I said earlier in this thread, I'm no longer too worried about the VCM in a facelifted 2nd gen. I think the consensus here is that most people haven't had issues. I would further venture to say that those experiencing issues of vibrations, shudders, etc ought to look into the trans software update first.

Additionally, I mentioned that I was going to buy a VCM for the 2008 Odyssey - sorry to disappoint but after further consideration, I figured it might not be worth it to throw a controller on an engine that has already experienced 14 years of running Honda's original VCM system. However, the 105k service is coming up within the next 6 months for that car, and I'll be doing that in my garage. It'll be interesting to see the conditions of the 3 plugs on the non-vcm cylinders compared to the 3 plugs on the vcm-controlled cylinders. I will definitely share pics and experience when that job is done.

 

FYI I had plug fouling and oil consumption with my RDX starting around 90k miles. I installed S-VCM and the oil consumption stopped completely.

You could definitely wait to install S-VCM until you start to notice issues. I would just be sure to check the oil regularly to see if you are losing any between changes.

When my plugs fouled, I was of course 2 hours away from home driving to a long weekend camping trip. I ended up changing my spark plug in the parking lot of an AutoZone. I now keep the necessary tools and 2 extra spark plugs in my RDX in the event it happens again.

I would suggest getting ahead of the issue and adding S-VCM, but obviously everyone's advice may be different depending on their own experience.

 

Interesting, I am eager to see what the plugs look like on ours when it's due for the timing belt and water pump here as well. With covid and less driving though, idk how long it'll be until we cover the final15k in that car before it's due. Might just do the job for fun next summer. The car was meticulously maintained, never missed an oil change at the same dealer it was originally purchased, so seeing the state of plugs with "honda recommended change intervals" will be great information. If they look fine, great. If not, that will be a significant argument for all owners to get a VCM, as regular oil changes and maintenance may not prevent fouling.

Speaking of which, now might be a good time to ask if anyone knows which cylinders are deactivated on a J35Z2? I know the first generation of honda VCM deactivated all rear banks by manipulating the valves in the rear head, but for some reason I think i recall someone saying that vcm is now offset? Like cylinders 1, 4 and 5? Idk maybe I dreamed that up.

I suppose I don't even need to wait for the 105k service to pull and inspect plugs, that's pretty easy.

 

For reference: I bought my RDX at 70k miles. It had all regular service done at the dealer and was well maintained. I did notice some oil consumption right away when I changed the oil for the first time around 77k miles. I think it was exactly 92k when the plug fouled. If you haven't seen any oil consumption your RDX is probably in better shape than mine. Mine was burning about a 1-1.5 quarts of oil between changes before I installed VCMTuner II.

When I changed my plugs, the rear 3 were much worse looking than the front 3, so I would assume those are the ones disabled with VCM. You'll probably get a good idea as to the state of your vehicle by comparing the rear plugs to a front plug.

The beauty of driving a Honda is that it's super easy to change out the plugs. Hopefully deactivating VCM prevents any of my plugs from getting fouled in the future, but I may replace them every 50k miles or so just because it's cheap and easy.

 

Dang, my old BMW didn't even burn that much oil. And yeah, further research shows it looks to indeed still be the rear bank of cylinders.

And honestly, seems a bit overkill? I'd say you have a bigger issue on your hands if you are burning oil and needing to change plugs every 50k, when a can of seafoam and some spirited driving could likely remove any significant buildup....but to each their own I guess.

 

Luckily my RDX is no longer burning oil after installing VCMTuner. You're probably right about 50k being overkill on changing spark plugs. I think I just have PTSD after getting stranded in the middle of nowhere when one fouled last time.

 

I have a 2014 and before I put on S-VCM in cold weather the experience was horrible. It didn't burn oil but the car would shudder so bad at certain speeds and it was very noticeable when the deactivation occurred.. I took it to the dealer and referenced a TSB that said the rubber on the drive shaft was known to fail in cold weather but they said it wasn't covered under warranty in Canada for a replacement which made no sense.... Anyhoo I installed S-VCM and haven't looked back. It runs like night and day and I have about 20k put on it since in just over 12 months with zero problems. Plugs are not due for a bit in my case but I will be paying close attention to them when they are. Mileage also hovers around 8.5l/100km mainly highway on average using a lot of cruise control.

 

From what I gather as an RDX & an Odyssey owner the model year matters with how the VCM operates. The mid cycle refresh RDX (2016-2018) have VCM set up that shuts down all three rear cylinders. This is also the way a 2018+ Odyssey operates. So it is the 2013-2015 RDX & older Odysseys that have extreme VCM issues. The favorite muzzling device over at the Odyclub is VCMTunerII-Advanced. It also reports actual temp in overheating situations (pretty rare in a Honda) it also reports actual temp when idling for a bit. This can help with diagnostics and idle relearn procedures. They come with leads to use for a switch if you want. They are made in California and he did the work to get them 50 state legal. Even CARB states.
The VCM barely saves any fuel. It only adds up for CAFE rating for Honda Corp. I have not muzzled my wife's 2016 RDX, but use a Muzzler on my 2015 Odyssey. It really makes it into a much better vehicle. The trans software is also worth it. My Honda dealer did it happily, the Acura dealer would not!

 

I also had the transmission software updated a few months before the SVCM. When I had taken it in to report the issue this is what they did. I had complained about a code that was showing up as well but I think they reset the battery to clear it because it just came back later. Ended up being the AWD relay which I changed on my own for a few dollars. My situation was that the issues were really bad in the winter when it got more than -10 celsius here. When they did the updates we were heading into warmer weather and I didn't think about it further until it started to hit late fall and the issues started returning. That's when I added the SVCM. IIRC mine also will display the real temperature if some upper limit is hit and has a fusable link for easy disengaging. I have a relative with the same gen/year Oddy and they also installed SVCM to get a more consistent operation out of the motor but didn't have any of the vibration issues I had. Very similar to what egads is saying.

 

Thanks for the feedback everyone, this is very valuable info in general for all of us.

 

When did Acura release the ECU flash update? I used a S-VCM controller that worked for about a year but has now failed. I started getting fluctuating coolant readings and hard shifting but went away when I disabled it.

 

You disabled it by removal or fuse removal and it started operating normally?

 

There have been known issues with S-VCM units failing. Apparently the seller is very good about replacing the bad ones, even if the warranty has expired.
I suggest contacting the S-VCM seller for a replacement. .
At the current time, the VCMTUNERII Advanced is also unavailable because that seller had a run of bad components causing failures. Hopefully that will be
solved soon.

The transmission software update is a separate issue, although they can mimic each other. I have a 2015 Odyssey that has the same engine/transmission as the 2013-2015
RDX. (6speed trans is the same as 2016-2018) I never experienced the "juddering" of the transmission until I muzzled the VCM. My muzzle device is the original VCMTuner,
with a dial to change the coolant reading offset. They still sell that one and I think it is fine if you live in a fairly steady climate and do not worry about overheating.

If anyone is interested in these service bulletins ( the trans software is one of them) they are all listed, by model year, in a dedicated thread above. There are several
on the transmission, but they just revise procedures and reporting requirements for techs to get Honda/Acura to cover the work. One must complain about a "judder" when shifting
and be willing to wait or leave the vehicle for this service. It must be done by a certified tech, not one of the dealers quick oil change folks. My Honda dealer did the software easily,
with me willing to pay for a fluid change. So far my Acura dealer has not been as cooperative. NOT doing software updates seems to be their kink. I endured endless Acuralink
texts about a low battery, for which there is a software fix, and never got them to apply it. I had to cancel Acuralink to get it to stop. This is of course mute now because Acura used 3G
for the cell radio, now dead.

 

I pulled out the positive lead. It was also shifting hard randomly but that stopped too.

 

Is this the 'transmission software' service bulletin to reference?
TSB 17-017 - 2013-17 RDX: Judder from the Torque Converter Lock-Up Clutch (Snapshot Upload Required)
http://www.urvi.net/forumfiles/SB/B17-017.PDF

 

Yes, that's the correct bulletin.


RFT!!!
Dave Kelsen
--
In England, “booster shot” is spelled “borchestershire shot.”