Hi everyone, hello from Toronto, this is my first post on the forum.



I’ve recently bought a new to me 13 RDX tech white/ebony with 135k km (84k miles for our American friends) for around CAD15000 (again, about $11500 for our American friends).



Car is in pretty good condition, four brand new tires, and a set of decent winter tires on rims were included as well, has been serviced at local Acura dealer since new. I’ve talked to the mechanic who has serviced this very car before buying it, he said that the previous owner never missed a single service and never cheaped out on anything. And he was kind enough to print all the service records on their system for me. I could see that the timing belt, tensioner and water pump were replaced @113500km, which was such a relief.



With all the above mentioned good stuff, I thought I’ve grabbed a nice car, but during the first week driving it, I started to notice the well-known judder issue when accelerating from 30-50kmh, as well as the “self-braking” when coasting toward red light. It was just embarrassing. What’s interesting was that I didn’t notice any of these when test drove the car at the dealer. Guess I was just too carried away by the fact that the car was dealer serviced and should be in good condition. Lesson learnt, pay 120% attention when test-driving, no matter how good you think the car is.



Initially I thought maybe all of the rough shifting and accelerating were because of the free tank of gas that came with the car. I know the dealer would never put premium in any cars especially after they have collected my money. So I waited, patiently, almost emptied the tank, and filled it full with premium, nothing has changed. Again, I thought maybe the ECU needed more time to get used to the “good stuff”. Two more tanks of premium gas later, still no improvement whatsoever.



So I did what any intelligent person would have done, went on the internet and start researching. Thanks to this forum and OdyClub, I have pinpointed the issue, and ordered a VCM tuner2, which arrived this afternoon. Because I’m a sucker, can’t wait for the next morning, so I’ve given the engine about 3 hours after work to cool down. After dinner, took my 10mm wrench to the garage, and started to get dirty.



I don’t know about you guys, but I personally think the engine bay on RDX is just not big enough to work with, I ended up with several cuts on my hands. This was not the case on the YouTube instruction video, where the guy just casually installed the thing, like it was a piece of cake, the whole video was just 8 minutes long, which includes his voice-over product introduction. Guess I’m just not mechanically inclined. Anyways, 20 or so minutes later, the little box was resting behind the battery, and the ECT1 sensor had a new spouse.



Now, moment of truth, went all the way the the furthest bedroom to grab the key fob, which, according to the installation instruction, was supposed to be some 30 feet away from the vehicle. Ran down to the garage and started the car. NO CEL on, thank god! Cause the engine was still a little bit warm when I installed the thing, and I was honestly a little worried, because I don’t have an OBD scanner to clear the codes. Lucky me.



It’s 9pm, and here I was, driving on some neighborhood streets, testing acceleration and coasting. All the problems, the judder, the self-braking, GONE! Like completely gone. I can not describe how happy I was. Later I went on some highways doing 110kmh, and the total testing distance was about 50km, no problem of any kind, no CEL, no weird noise, just simply smooth driving.



Personally I would say the improvement to drivability was night and day, no less. In terms of MPG, I think I would need more time to see, but initial thought, not something I would worry about.



Now I did notice a couple of things. First off, the temp gauge was at the same position as prior vcmtuner installation. Seemed like nothing has changed. I thought it was supposed to be a little lower than usual, but on my car, it just sit right below the middle, about 2 marked lines below the middle line, which was exactly where it was at temp before vcmtuner. And second off, the idle rpm seemed a little higher than before. Attention to details is one of my things, I know that the car idles at 650rpm previously, now it’s somewhere between 680-700 rpm, is that normal?



I would hope folks here who have installed the same or similar stuff on their cars would chime in. Thank you.

 

The product works well. I installed mine a few year back , then took a 1200 mile road trip to the big apple and back. Averaged 29 miles to the gallon and was well pleased. If you have the vehicles records for maintenance , check and see when the last transmission fluid change occurred. If not in the last 30 to 40 k miles ,,change it out. Mine is all wheel drive and change it out every 30 k , trans, rear diff and trans axle . I use Valvoline max life syn in the trans and the Honda fluids in all the other spots.

 

Hi Eugene,

Thanks for the post! My S-VCM is currently plodding its way to my home and should be delivered Monday. I'm planning to connect it to a switched fuse in the under hood box instead of directly to the battery. It'll be nice to have all six cylinders cranking out some ponies without having to drive around town in 'S' mode all the time.

 

Thank you for the reassurance and good advice, Poolman. I have then checked the printed service records, apparently the mechanic was not lying. Previous owner has changed almost all kinds of fluid for the car, he even put on two new struts right before the car was traded in, lucky me. Those stuff were not cheap at Acura dealer.

 

And I was looking at the price of the timing belt/spark plugs and all that, holy crap, so glad they were done just 20000km ago.

In terms of MPG, I have driven the car for a little over 2000km since I had it. Reset the trip B to 0km when I took over the keys from the dealer, and set trip A to auto reset after each refuel so that I could get a clearer picture of mpg. Overall the computer shows 10.3L/100km (22.8mpg), it’s more like 21.5-22mpg if I really do the math. There were about 800 highway km and the rest daily commute (Toronto and GTA, stop n go, average speed 30-35kmh).

For the road trips, I did manually calculated the mpg, I was averaging almost exactly 27 on the highway. For my most recent commute tank of gas, computer shows 11.8L/100km (20mpg), again, human math indicates a bit over 12L/100km, so 19mpg.

For whatever reason, my real world mpg is identical to EPA rating. I have muzzled the VCM about 700-800km ago, and I’ll keep monitoring the mpg, but I really don’t think the VCM tuner has any huge impact on gas mileage.

 

thanks for the reply, I don’t know about other folks, but I’m definitely very satisfied with 6 cylinders running the entire time.

only thing is, when installing the thing, it’s such a pain to get to the ECT1 sensor, I was this close to give up, and say F it, then drive to my mechanic. So good luck!

 

Calculated MPG is always lower than what the vehicle computes on its own on every car out there. What's interesting (to me) is that there does not seem to be any specific rate of variance. Sometimes it's off by 5%, sometimes 3%, sometimes 7%.... I don't waste my time with the display in the car except to know if I'm trending in the right general area and to help me to make improvements where possible. I use Fuelly to track everything I spend on my cars and it gives me correct numbers to work with for everything PLUS a service record. And, I can export everything out from my account on the web site and throw it into a spreadsheet to total up everything any time I want. Otherwise, Fuelly shows me the cost per mile for gas right in the dashboard.

 

I've seen other posts from owners saying they came away from the project with scraped knuckles. In anticipation of this issue I tried unplugging the sensor on my '17 and it was a snap...literally. Reach down with palm facing the connector, press the release tab and lift. Done! Unless I'm an idiot and pulled the wrong plug

 

Depends on your speed. On my last run on the 401 when I went to the motorcycle show (so that was last February), I got between 6.6 to 7.2 L/100 km over a 200+ km flat stretch cruising at a true 100 kph. Hell if I want to go fast, I'll get in the 911. LOL

The RDX with a 3.5L V-6 gets far better mileage than my 1st gen CR-V with a 2L I-4.

 

Heck I must have unusually big hands, I just couldn’t get it to work in the first ten minutes trying, and when it’s finally done, several cuts on my right hand, like I just murdered someone...

 

Thats is a good one, I’ll definitely download and try it out.

 

I almost don’t believe you, unless you are talking about from Kingston to Toronto, if you were to do it from Oshawa to Etobicoke, I doubt you could achieve that mpg, it’s insane. I don’t drive fast, and I try to coast as much as possible. I would be more than happy with 8L/100km on the highway, and 11 in city.

 

Trust me, I ran a metrology lab. I know something about measurements. I also have it via calculation (distance travelled & liters used). Obviously not in bumper to bumper traffic.

 

I also use the Carfax Care App to track my gas fill ups. I use that app to keep track of my maintenance as well.

 

Bringing this thread back around to the original subject, My S-VCM is installed. It took a whole seven minutes and five seconds. It would have been less except the module comes with several very small zip ties that I burned a bunch of time with trying to use. Note to anyone who does this install in the future, grab a couple of longer (8") zip ties and snip off the extra. You'll thank me later.
Anyway, as others have noted, with the module in there's no more 'downshift jerk' when slowing to a stop. The big change is accelerating from a lazy cruise. That little hesitation while three cylinders light up and begin producing power again is gone. All six cylinders are now working full time.

Here's a picture of the unit installed. It's zip tied to an existing harness.



These pics the before and after temperature reading which means the module is working exactly as expected. It fools the car into thinking the coolant is cooler than it actually it is so VCM isn't activated. The dashboard temperature gauge looks normal.

 

I purchase the S-VCM for my 17. I have not installed it yet. Did you connect the S-VCM to the fuse box, if so do you have pictures. Do you service your car yourself?

 

So I have no idea what a VCM or a VCM tuner is for. Is there a reason I should consider doing this?

 

It allows you to turn off Variable Cylinder Management (allows the engine to turn off some cylinders to save gas), which can make your car jerk around and have issues if you're unlucky.

 

My original plan was to use the fuse box but ended up just connecting to the battery. The positive terminal is only a few inches away from the S-VCM module (running the wire 'under' the intake tube) and there's negligible current draw.
The only service my '17 has needed are oil changes and tire rotations that I do myself.

 

And I thought just the opposite when I bought my 2017 RDX. I was impressed as to how much room there was especially with a V-6 in it. Have you seen the amount of room behind the engine to the firewall? Lots of room.

If you think you have no room in an RDX engine bay, trust me, you have not worked in a Porsche 911 engine bay. I call it an exercise in patience and when that happens, I walk away and watch some TV for a half-hour. Sort of reminds me of Yosemite Sam at times.

 

I think most do but I installed an insulated jumper so that I can disconnect the S-VCM without the need for tools. Don't know why I would need to but the option is there.

 

I am just about to install the thing right now..however if you all watched a video about this like i did..the guy takes apart an engine with vcm and shows the tremendous damage caused by this dumb system..though on my personal conclusion i decided that i will turn off the vcm system and keep all 6 cylinders running forever..i will not restore the vcm system ever again..according to the video that vcm uses engine oil in order to operate..so i assume that having vcm parts just seating there for a big while with no use and no lubrication can cause some sort of problem when rengaged..again thats my personal opinion

 

Do you have a link to that video?

 

Hey guys.. reviving this thread again. Posted this comment on another VCM thread the other day. But I just recently heard about VCM and the issues it "may cause" on other Honda V6 owners. Here I am thinking to myself that this was such a great technology too!

First question I have is.. when does VCM kick in? It's not the downshifting feeling when approaching stops is it? I always thought it was a little annoying but I always also assumed it was the transmission actually downshifting and not VCM? It typically feels like it would literally downshift through a couple gears. Would VCM be kicking on a couple times when's coming to a stop?

Cause if it was the VCM, wouldn't I only feel the little hesitation once and not cycling through a couple gears? Just an observation I've had on my car. I'll check again later when driving but I could've sworn that downshifting feeling happens at least a couple times when coming to a stop. The second downshifting being very subtle.

I have a 2013 RDX Tech with about 90K miles. Bought in 2017 as a CPO with about 53K miles. When I first bought it I did notice a jerk in shifting from 1st to 2nd or sometimes 2nd to 3rd. Luckily coming from a Mazda 6 that had this same issue, we Mazda heads called it shift shock. So I Googled it for our car and sure enough there was a TSB for a TCM software update on the transmission. It also called for AT fluid change. Sure enough that completely fixed my issue. I've read some people claim that was VCM but I think they are getting it twisted.

If getting the VCM tuner alone will remove the downshifting feeling I actually might consider purchasing one. Cause tbh I really don't notice it any other time. I thought it only turned on during hwy driving which would make sense since the car doesn't need much power when coasting. But I don't feel it on the hwy either. Car seems fine. No excessive burning oil issues.. Do you guys recommend the VCM Tuner II from vcmtunner.com? Are there any other great alternatives that isn't as pricey? It's also sold out right now too..

 

My understanding going back is this is two separate issues. Yes, if so controlled, Honda automatic transmissions downshift (especially on a downgrade) when slowing down...whether they're VCM equipped or not. My 2007 Ridgeline, 2012 TL, etc. all downshift when slowing down and they're not VCM equipped. I think the complaints came with some RDXs downshifting in a non-linear "herky-jerky" fashion...and several folks noted that their installed VCM deactivation devices removed the "non-linear / herky-jerky" out of the downshifting process when slowing down, making it smoother. This is what I recall and understood at the time.

 

Hi,

I know the post was 4 years ago. I just bought a 2014 RDX tech AWD. I installed VCM tuner2 today, to the location shown in pictures in this thread, no engine code after the installation.

I noticed exact same things as Eugene, idle rpm slightly higher and temp gauge SAME AS BEFORE.

Now the concerning part, I used OBD2 scanner to read ECT1 temp, it is 185F, the same as before I install the VCM tuner2. With this, I am not sure if the VCM tuner2 is actually working or not.

A little extra, I noticed the fan is on and off frequently while in parking. Like on for 5 seconds, off for 2 seconds, on for 5 seconds, off for 2 seconds ... I didn't pay attention to whether it was behaving like this (before installing the tuner2). May need to take off tunner2 to figure out.

Anybody has any thoughts?

Thanks.

ZG

 

To answer my own questions:
1. After work, did a drive again and measured ECT1 with OBD2 scanner, now it stays at 165.2F (74C) in both driving and parking mode, just as designed. Not sure why this morning, immediately after installation, when I drove around and then measured ECT1 while parking, the reading was 185F, same as before installing Tuner2. (Comparing the photo taken on temp gauge, it is now about 1/3 tick lower than before).

2. Fan on/off very often seems to be common for Acura. If I turn off climate control completely (not even blowing air), the fan seems not doing the on/off.

Thanks.

ZG

 

Yeah for me.. if the AC is on.. the radiator fan will kick on frequently. But this was with all cars I've owned. No AC on.. fan doesn't come on as frequently.

 

Thanks t0md0 for your input.

In my case, after driving a couple of miles on highway then park in the garage for 5 minutes (A/C off, only blowing air at lowest speed), the fan will be on for a few seconds, then off for a few seconds, then keep repeating this pattern, which is different from my other cars. My Honda pilot will run the fan for a couple of minutes then off a few minutes, so in a less frequent manner.

If I turn off the air blowing on RDX, then the fan immediately stop doing the frequent on/off.

Thanks.

ZG