Light Acceleration Stutter..VCM or Trans?

[Aurora85]

I noticed tonight and a few days ago a shutter under partial acceleration between 2 & 3rd gear on a flat road. Its like it was hunting for a gear, but never shifted. The ECO light was off as I was accelerating away from a stop light. I thought a few days ago that it may be a transmission problem , but found some threads on here from a few years ago that mentioned it could be a VCM issue and is possibly related to oil level. Folks have mentioned if the oil is low their engines sometimes exhibit this behavior. Its raining outside right now otherwise I would check the level, but my MM is indicating 30%. I'm hoping its due to oil and Ill just go change the oil. I'm more worried about a tranny issue, but the transmission fluid shows perfect red and clean. Under firm acceleration , the car has no issues. Wondering if anyone has experienced this since that thread in 2010? I'm going to mention to the dealer about the Transmission TSB that I found as well.

Thanks for any advice/info

[gooderthanyou]

I have an 08 V6 AT. Yup get use to it, still have stuttering/hesitation every so often. What I learned to do is to drive the car a little harder than I use to. If a hill is coming up, give it acceleration early, try to keep speed otherwise the car with drop gears, think about it for 3 seconds, then decide switch gears.

I find changing AT fluid so often helps.

The VCM is the culprit from what I know. I think there's 2 modes, 3 cy and 4 cylinder. One of these makes a "Droning noise" when it's on. I think VCM should just be on at highway speeds or 40+ mph. I really don't care if it saves me 1MPG in city driving.

I had my ECU updated a while back, while i'm not entirely sure they gave me the newest update or not, it didn't seem to help. I might try again at some point but I hate to pay $100 for something that won't work.

[Aurora85]

Glad I'm not the only one, but this was with VCM not even engaged . I'm at the point where I bought this because its a Honda, but my confidence in the car being reliable is starting to wane. I've read some horror stories on Edmunds forum about folks with complete engine failures at 75K miles and others with cylinder and plug issues. I love the power of the 6, but I wish there was a way you could have purchased the car without VCM. Seems to add to much complexity without much gain.

[Metal Metalic]

Originally Posted by Aurora85

Glad I'm not the only one, but this was with VCM not even engaged . I'm at the point where I bought this because its a Honda, but my confidence in the car being reliable is starting to wane. I've read some horror stories on Edmunds forum about folks with complete engine failures at 75K miles and others with cylinder and plug issues. I love the power of the 6, but I wish there was a way you could have purchased the car without VCM. Seems to add to much complexity without much gain.

OK

Peeps are miss-guiding you.

I must make a point, when ECO mode is active VCM is active.

Since the OP has stated his issues are for the most part, when VCM is not functioning.

I have a 09 V6 coupe with an automatic, and have been trough a few phases of upgrades to allow better low end torque.

During my assessments of each phase, I noticed the lack of torque in VCM mode being the contributor to most VCM shudder.

But it is due to 3 things all not related to VCM function at all.

Automatic down shift from OD gears. All late model cars will not allow acceleration in OD.

Air conditioning kick in. If running heating and air in auto mode, transmission kick down may activate due to load on the engine. Even if at steady cruising speeds.

RPM range, is also another issue. The sweet spot for the lack of a better term, where engine torque lacks just enough to keep the RPMs with a bearing load in steady motion.

I am not pushing upgrades will cure the issue completely, but each of my upgrades do work well at keeping such issues tamed down to just one wee quirk just above 77 MPH with cruise control on and VCM.

Here is a short assessment of what I have found with adding more low end torque.

MDX spacer... Adds enough torque to allow a more stable RPM while highway cruising in VCM. You can accelerate with a light throttle while ECO mode is still active.

Resetting ACM per Honda recommendation (Don't have the TBS #).

DTC Clear and ACM Reset:

With engine off and key out of ignition.

Insert key and follow the procedure below.

1) Turn the Ign Switch to Lock

2) Turn the Ign Switch to ON II and wait 30 seconds

3) Turn the Ign Switch to Lock

What this does is allows the automatic grade logic to be more friendly with coasting and part throttle conditions.

I have fully tested over a year, and found it worth while, as grade logic will activate less harshly and I don't need to keep the accelerator into coasting to a stop or light under 30MPH.

Lastly, as an easy to install budget item to add more low end torque. My not so wee secret for automatics only. :o)~

To add a manual IM cover from an 09 on up Acura V6 with an IMT valve. Make sure the flapper is in the closed position before installing. Though our VCM engines do not have the electricals to allow opening and closing, the IM cover will add about 10 more to your low to mid range torque. It will take away from high RPM, just as much as the MDX spacer. The nice thing is that you can always put your original IM cover on at any time (15 minutes to do the swap).

Though I have a completely functioning setup with a mod to allow its function, the drivability differences will only be that my setup will allow better high range RPM power by opening the valve. Though leaving the butterfly valve open will not be as good as having the Honda VCM cover left on.

Honda has made a few steps to alleviate the noticeable issues with 9th gens, here are a few.

1) 6spd automatic
2) Alternator decoupler pulley
3) Low tension drive belt tensioner
4) Revised intake manifold design

Since 8th gens have no such design updates, the only option that will make a very small improvement is to add the alternator decoupler pulley if you have done the upgrades I have stated.

As for the drive belt tensioner... I have found that Honda has pulled a fast one.

Early 8th gens have a different tensioner spring setting, and possibly mid production 8th gens have a hydraulic tensioner actuation, leaving the late production 8th gens with a different pre-load than all the others. Since I have not the energy and money to find out the best tensioner for 8th gens, as if it really matters... Replacing a tensioner will be a bit overkill for the price and function as the decoupler pulley should do fine under all types of tensioner pulley setups.

[Markus]

I battled with Honda with this very issue for more than a year. Honda's response ranged from "they all do it" to "we have no idea what the problem is" to, finally, replacing the transmission AND ECM. These were both replaced at the same time and the problem was fixed.


The droning issue is separate and had become worse and worse on my car. Honda now thinks the droning is caused by worn out active engine mounts. There is a reason, I guess, that the engine mounts only have a 3 year warranty rather than a 5 year warranty.

My Honda is is the last one I will ever own.

[Metal Metalic]

Originally Posted by Markus

I battled with Honda with this very issue for more than a year. Honda's response ranged from "they all do it" to "we have no idea what the problem is" to, finally, replacing the transmission AND ECM. These were both replaced at the same time and the problem was fixed.


The droning issue is separate and had become worse and worse on my car. Honda now thinks the droning is caused by worn out active engine mounts. There is a reason, I guess, that the engine mounts only have a 3 year warranty rather than a 5 year warranty.

My Honda is is the last one I will ever own.

I hear that! Though you and a wee few others have been more or less not the norm as for auto tranny failure and difficult repair issues.

Now you did have a bit of mileage over mine, and I had flushed and filled with synthetic and added a magnafine a month after purchasing from Honda (13.5K on the ODO).

Maybe Honda was right in going synthetic with 8th gens in mid production. Donno

As far as ECM programming... the only one I can think of is the transmission clunk fix, that could carry over into tranny life as well.

I can't remember, Markus, you do have an 08 or 09????

Well anywho... 9th gens may have some improvements, but I don't care for the stylish appearance and the cost cutting redesign of the upper engine along with the bodies suspension.

Only if Toyota would make a coupe again... well a mid sized coupe. :o)

[gooderthanyou]

Originally Posted by Markus

I battled with Honda with this very issue for more than a year. Honda's response ranged from "they all do it" to "we have no idea what the problem is" to, finally, replacing the transmission AND ECM. These were both replaced at the same time and the problem was fixed.


The droning issue is separate and had become worse and worse on my car. Honda now thinks the droning is caused by worn out active engine mounts. There is a reason, I guess, that the engine mounts only have a 3 year warranty rather than a 5 year warranty.

My Honda is is the last one I will ever own.

Yea i'm pretty much not going to buy a honda again either. I've called their customer support and been hung up on or argued with as to "why do I think I have a problem".... unbelievable. I am 5 months from paying it off, so I hope to get 5 years out of it and live out the "annoyances" I have with it.

Another thing, from the brake fiasco, I just had my rotor replaced in the rear. Apparently the honda brakes that I had replaced at 30k or so had "molded" to the rotor so when I replaced the brake pads I could hear noise from the rotor being uneven. IT was such a PITA to get them to replace the brakes to begin with, had to come back 4 times to the dealer.

It doesn't feel like my car is going to explode or anything, I think most companies see it as "is it a safety concern? No? Okay then."

Markus when did you get a new engine and tranny, I wonder if the 10' and newer models fixed the problems and that's why you are having no issues now.

I read some posts in the '13 forums here and there's already a few V6 users talking about the VCM and if it's "Normal".

On the other hand, my fiance drives my car and loves it and doesn't seem to notice any of the issues I complain about

[gooderthanyou]

Originally Posted by Metal Metalic

I hear that! Though you and a wee few others have been more or less not the norm as for auto tranny failure and difficult repair issues.

Now you did have a bit of mileage over mine, and I had flushed and filled with synthetic and added a magnafine a month after purchasing from Honda (13.5K on the ODO).

Maybe Honda was right in going synthetic with 8th gens in mid production. Donno

As far as ECM programming... the only one I can think of is the transmission clunk fix, that could carry over into tranny life as well.

I can't remember, Markus, you do have an 08 or 09????

Well anywho... 9th gens may have some improvements, but I don't care for the stylish appearance and the cost cutting redesign of the upper engine along with the bodies suspension.

Only if Toyota would make a coupe again... well a mid sized coupe. :o)

I had the ECM transmission clunk fix done, it worked! .... about the only thing that has lol.

Also I've been doing DW-1 and getting rid of that crappy Z1. Which also makes a difference. The entire reason I bought honda was for peace of mind, I shouldn't have bought a new car. I think next I'll buy a $15k car with at least XM and power windows, that's about all I want. I won't feel as bad as this $26k car I bought!