Hey,

Been driving my 14 RDX for a month now. I came from a manual transmission Subaru WRX, so this has been quite the change for me. Any who, I'm hoping somebody can clarify this phenomenon I'm experiencing. So, sometimes i’ll be cruising along at about 40-45 mph and the car will be in 5th gear (i think) at about 1300 rpm. If i need to increase speed or i start to climb a hill, in anticipation, ill naturally apply gas pedal to about 1600-1700 rpm and can feel the car bogging down a bit. Next, ill anticipate a down shift to say 4th gear, with an expected increase in rpm that comes with a down shift. But, in fact, what i experience is the complete opposite. Instead of a down shift to say 4th gear and a increase in rpm, the car drops a solid 500 rpm (almost like an upshift i gears) but i gain power and the car accelerates. Is that the VCM shutting off and the car going back on all 6 cylinders? If so, its kind of annoying to say the least... might consider muzzling that feature...

 

Muzzling is the answer. (well, you should also make sure the transmission software has been updated and the fluid fresh)
There are several types of muzzlers all doing the same thing in increasingly sophisticated ways. Basically they all plug between the coolant sensor
(well one of them) and the engine management system. What they do is fool the system into thinking the engine is not quite warmed up enough for
VCM to activate. The original ones where simple resistors that worked most of the time. The next up had changeable resisters so one could tune it
to conditions. The next one had a dial for that. The last two adjust themselves automatically.

Here are the four biggest names in this:

https://www.ebay.com/itm/VCMuzzler-I...-/172807770690

https://www.vcmtuner.com

https://www.svcmcontroller.com

https://www.vcmtuner.com/products/vc...e-vcm-eco-mode

The last two adjust themselves and require a wire to the battery. The S-VCM can be ordered with the option to have a switch at the dash to shut it off

The VCMTunerII Advanced comes with wires to do that (you don't have to) and also reports the real temp to the engine management system if idling for a period of
time to allow for diagnostics requiring that. Both the S-VCM and the VCMTunerII will show an overheat situation on the dash gauge.

Depends on how much you want to spend and how much the ambient temp changes where you live and travel. You can get by with the cheapest ones if you don't mind it
VCM activating sometimes. If never, go with the most expensive.

There is not a lot of discussion about this around here. Partly because the Acura has such good engine mounts and many folks do not keep their cars beyond the lease period.
If you want to really know everything about them, look at some forums devoted to V-6 Accords & Crosstours, Odysseys, Pilots and Ridgelines. One of the first devices was developed
by a guy with a Ridgeline. Oddly, while this system helped Honda achieve Corp Average Fuel Economy ratings, individuals find little if any fuel economy hit. Some even find an increase.

Many sellers may lay it on a little thick in their sales pitches. Ignore. Honda did have some serious issues when pairing VCM with some experimental low friction piston rings. Our Acuras
never had those. Also, starting with the 2016 RDX anyway, the VCM system shut down 3 of the 6 instead of the system in your 2014 that did 3 or 4. Those seemed to have been much more jerky.

And: as I said initially, when the VCM activates/deactivates during a shift point, it really seems bad. Make sure the trans is serviced. Many folks new to Honda do not know how critical
(and normal) trans fluid changes are. A normal drain & fill only replaces 1/3 of the fluid. That is normal maintenance. If one has issues or if the dealer is performing the service bulletin
on the trans, then the fluid changes are done 3 times in succession with driving (more than around the block) in between. If dyi, one each of three weekends works. NEVER let any place
"flush" a Honda automatic.

 

Has nothing to do with VCM. Your torque converter might be slipping a little. When it eventually locks up, you get the RPM drop and a direct push forward. Since you come from a stick-shift, think of it as slipping the clutch a little and then letting it engage. Try using the manual shifting mode (S) to see if you can replicate this behavior shifting your own gears with paddle shifters.

Depending on how many miles you have, I would do a trans fluid change - that may cure the hesitation/slippage.

I used to drive a Forester XT manual before the RDX, so I can relate.

 

oh man dont tell me that! This thing is a beauty, only 43,000 miles. I see a trans change was done at 20,000 on my carfax...

 

The Technical Service Bulletin I referenced in my post:

http://www.urvi.net/forumfiles/SB/B17-017.PDF

See if you can get a dealer to perform it. Present using the term "juddering" They are able to cover that even if out of warranty.
Once done, plan on having the transmission fluid changed every 30k minimum (the factory recommended interval) or every 15k (every other oil change) if you tend to be obsessive or diligent.

I'd still muzzle, but that is only important if you plan to keep it long term.

 

I tried to replicate with manual mode but couldn't yet. Ill keep trying. Car seems to shift pretty darn smooth, in fact id say its almost butter smooth. As to the tsb, they will honor a car out of warranty? Also, when you say long term, roughly how many miles is that. Planning to put 100k on this thing before i unload it... i dont really like the idea of spending $100 on the muzzler if its really not needed. Something about the car not telling me its real temp just bugs me...

 

The car never tells you it's real temp. Folks over at the Odyclub have tested with OBD meters and found that once the vehicle warms up the gauge will
show normal. If for some reason it gets hot, like climbing a hill in extreme heat, only then will the gauge move at all. The dash gauge is not linear it just shows
something the ECM tells it.
The two most expensive Muzzling devices, the S-VCM and the VCMTunerII Advanced do take themselves out of the loop if the temp reaches a certian level.
If that happens, the dash gauge will show an elevated level. I have personally never had a Honda overheat. My first one was a 1976 Accord. Had at least 8 since.
(with overheating Mazdas in between)

I think what you are experiencing is related to VCM, but even if it is the transmission, (sometimes a combo) either or both are addressable. I don't think anything is failing.
The VCM in the Acuras is probably as good as it ever got. The Odyssey, Pilots, & Ridglines do have active engine mounts to isolate the VCM from the driver, but I bet the Acura ones are a step above.

I think I would at least try to get a dealer to hook up the trans to the service dept computer that is also connected to Honda/Acura. They might not want to do the whole fluid change out for free,
but you can get that done by just adding a fluid change to your next couple of oil changes. (if not doing it yourself) Changing trans fluid in a Honda is easier than changing the oil. There's drain plug
underneath and a fill plug on top. (although may fill with a funnel and hose slowly through the dipstick hole)

Oh, long term would probably be the 100k after the first 100k. Of course by then you might need a minivan...

 

If the car is shifting and responding as expected in manual mode, it might need to re-learn your driving style. Perhaps the previous owner was overly gentle with the throttle and the computer adopted an economy program, hence the slight hesitation. You can disconnect the battery for 10 minutes, then re-connect and drive the car aggressively for a few hundred miles and see of the normal automatic behavior becomes more responsive.

 

Well, i reset the ecu and trans... car seems to drive way better for me now. Ill keep the trans and vcm tips in mind moving forward. Going to start by seeing if acura will update my software and change the trans fluid.

 

bringing this back, im just about fed up with the drivability of this vehicle with this garbage vcm. From the above options you listed which muzzler is the best? Should i go with svcm or vcmtuner?

 

VCMTunerII Advanced

 

yea im reading up on it now. Looks like a nice option. Do you run one?

 

I have his original one with the dial. Could not buy the latest, I'm in California. It is still set to the default (45 I think) and works just fine.
Where you regularly live and drive matters with these devices, as they just alter the actual coolant temp reading. For some reason, folks
on this forum never fill out their location. I do have another Honda with this engine and may have one sent to my friend in AZ.

 

im in buffalo ny... any issues?

 

In a climate like that, I would want one of the two that adjust themselves. The S-VCM is the other one.

 

I'm in Buffalo, NY and I'm using S-VCM with no issues.

 

I just got my 18 RDX tech this month, coming from a 6spd accord, the RDX always felt like it was chasing gears and chugging everytime I let off the gas. I can also feel it hesitating whenever I go WOT.
so I ordered and installed the S-VCM. and oh boy, night and day difference, no more hesitation, no gear hunting and it actually feels like a luxury car now.

 

Another vote for the S-VCM Controller. I have been using one for almost 3 years now...works as advertised. Also...don't forget MaxLife Full Synthetic ATF in the tranny!

2013 RDX-TECH AWD - MaxLife ATF + S-VCM Controller

 

A lot of good info on here, just ordered S-VCM for my 16.

 

A question the the S-VCM-II.

Installed the S-VCM II over a year ago, just got ​​​a check engine light on my 2016 RDX. CEL P0118 coolant sensor high, and a P0128 coolant below threshold. I did monitor coolant temperature when it threw the code, S-VCM in place. I was reading 154 deg F consistently, as opposed to 167 deg F published by the mfg. Removed the S-VCM, checked the sensor resistance (within spec) and cleared the codes. Currently running without it.

Sent a message to the manufacturer (two weeks ago) no answer to date. Wondering if anyone else has had a failure of the S-VCM II module, and if any troubleshooting possible?

Considering putting it back in and watching it. If it still sets the code, will likely replace it as the car runs great without the VCM activating!

Thoughts appreciated.

 

You are not the first to have an S-VCM failure. Normally the guy who makes them is responsive to warranty requests.

The number 1 choice for such a device is the VCMTuner II Advanced for $20.00 more.

 

I'm a bit confused...could you clarify whether you have an S-VCM Controller -or- VCMTuner II?

 

I have the S-VCM controller.

Based on the reply above, I’ll dig into the VCM Tuner II. If I need to replace the S-VCM, I’ll likely go that way.

 

I haven't read of anyone on this (RDX) forum having issues with the S-VCM Controller...of course that certainly may not be the case with other users on other forums. I think if the same issue would've happened with the wife's RDX, I would've disconnected the power wire to see if a "power reset" would have cured the issue...though honestly, it sounds like your S-VCM Controller has died.

Let us know what response you get from the maker and what (if any) remedy he offers.

I'm sure the VCMTuner II is a solid unit...its maker was one of, if not the first to offer a VCM muzzler device. Good luck with however this ultimately works out and running on all 6 cylinders all the time!

 

Yes my reports on S-VCM failure are from being a member of the Odyclub (the odyssey uses the same engine) As I said above, the S-VCM vendor has been responsive to warranty requests.
There have also been issues with the wire going to the battery being compromised, either by someone replacing the battery, installer not routing wire carefully, or even rodent damage. But that is usually
a broken or about to break wire.

 

There's also a free way to disable VCM without throwing codes and takes about 30 seconds to do. Disconnect the bank 1 rocker arm pressure switch. It's the connector with a single wire on the rear bank. Just sayin' 🤷🏼‍♂️ I'm sure those VCM muzzler companies are making a killing!

 

You know, I looked through the parts blow ups and find that there are quite a few pressure switches. (three on each bank?) If this really does work without setting codes, it would be extremely helpful to have a photo or some foolproof way to identify the switch. Thank you so much for revealing this little secret.