Drivability issues in 2014 Honda Accord EX V6 - related to VCM or 6 speed trans?

[kjoiner]

Hello,

I've posted this question in an Accord forum, but I wanted to see if anyone here has better information of suggestions. I have a 2014 Honda Accord EX V6. This car has a 6 speed automatic and also has VCM. Since I bought the car, I have notice a few really irritating behaviors that seem to be a result of the search for better fuel economy.

1. Although it has a 6 speed, the transmission wants to shift out of 1st into 2nd as soon as the car starts moving. This happens well before the engine has a chance to get up to an rpm where the shift would be smoother. I've had several instances when pulling out into traffic that the car would short shift into 2nd and the engine would stumble - not a good feeling. Even in S mode where shift points are raised and the transmission will only shift up to 5th gear, the transmission will short shift - usually at the worst time.
2. When it shifts into 2nd, it seems the throttle body is being manipulated to close during the shift to the extent that the car stumbles as it shifts. It's like riding with someone who does not know how to drive a stick shift car.
3. When slowly rolling into the throttle, you can feel the car laying down a little bit.
4. The transmission is constantly shifting between gears. It seems that with a higher number of gears, the effort is to keep the engine at the most efficient RPM. With the issues I'm having with a 6 speed auto, I can't imaging what some of these 8 and 9 speed transmissions are doing.
5. At moderate speeds or when making a turn, as I go back into the throttle, (the car is in a higher gear and perhaps the VCM has shut the engine down to 3 cylinders) the car will downshift and suddenly "wake up" (can't think of a better term) to the extent that you can't apply smooth power - it's like an on/off switch sometimes.
6. Other times, when I'm accelerating, the power seems to come in steps rather than a smooth buildup.

I've complained to the dealer several times about this problem. There standard response is "we checked it, it hit all of the shift points and we re-flashed the computer). All of the behavior above is without "Eco Mode". The Eco mode numbs the throttle response in city driving so I don't use it unless I'm on the highway.

I do know that Honda's transmissions are parallel shaft types vs planetary etc. and behave somewhat differently. I had a 2004 Accord EX V6 with a 5 speed suto that never had these problems. Other drivers have complained about this issue but this is much more than annoying - having a car stumble when trying to accelerate is just dangerous.

I wanted to see if any of you could provide insight into the issues. I'm trying to find the right "magic word" or something to make Honda listen to me and realize there is a problem.

Thanks,

Kyle

 

[BrianPetersen]

1. Normal and common. But the 1-2 shift should be happening with the torque converter unlocked in order to cushion the shift and that also prevents the revs from dropping too far. Lots of automatics in this day and age do an "almost lug" in the interest of keeping the revs as low and economical as possible. Low-slip (low-stall-speed) torque converter, very early torque converter lock-up, early upshifts.
2. It's pretty common nowadays for the throttle to be co-ordinated during gear changes with the intent of minimizing shift shock. But it shouldn't be doing what you're describing.
3. I don't know what you mean by "laying down".
4. Yep. Welcome to CAFE of the "corporate average fuel economy" variety, not your local coffee shop. If you want the transmission to be in the optimum (usually most economical) gear all the time, there's going to be a lot of shifting. But the better ones do it pretty seamlessly.
5. It's normal for an automatic transmission to have upshifted to the highest-economy gear when rolling up to an intersection and it's not uncommon for it to be in the wrong gear for accelerating out of the corner. Some are better than others. But what you're describing doesn't sound right.
6. Doesn't sound right for a car built in this century.

Find a similar car on a used car lot and test-drive it and drive your own car on the same route. This will tell you whether the issue is specific to your car, or whether "they all do it".

If it's a "they all do it" and you can't live with it, it's time to trade in for something else. I personally hate CVT transmissions but they're ideal for non-enthusiast drivers who can't handle gear hunting or shift shock.

My own new car is of the increasingly rare row-your-own variety.

 

[MikeHalloran]

Squirt some SeaFoam into the port where the IAC valve gets its air, usually on the upstream face of the throttle body. Even better, feed some as foam (from an unused Dial Soap foaming handsoap dispenser, with the engine running.

Even easier, just add a pint of Marvel Mystery Oil to the fuel tank. If it's going to make a difference at all, the difference will be dramatic, and apparent in 20 miles or less.



Mike Halloran
Pembroke Pines, FL, USA

 

[gruntguru]

While accelerating, best economy will coincide with moderately "large" throttle opening (about 3" to 6" Hg on a vacuum gauge) and rpm somewhere near peak torque. If you maintain this throttle setting while accelerating, the trans should shift to keep you in the "best economy" band.

The point here is - if you use the "best economy" throttle setting, the trans shouldn't short-shift.

je suis charlie

 

[kjoiner]

Hello,

Thanks for answering my questions.

Brian,
1. It does seem like the transmission wants to lock up the converter as quickly as possible. Right after the 1-2 shift, I feel a couple of bumps and it seems like the converter trying to lock or maybe the VCM doing something strange. I agree with the lugging and the attempt to keep revs as low as possible but it seems like the auto makers are pushing it too far. I remember when driving a stick and the wide gap between 1st and 2nd would lug the engine unless you let it rev a little. With today's automatics that's not allowed. What's alarming is if I try to get into the throttle from a standstill, the computer would recognize that I'm trying to accelerate rapidly and to hold the 1-2 shift longer but instead it hits 2nd before the engine can build enough torque to handle the higher gear. In my opinion, 1st gear in this car is almost useless. I'm certain it could pull 2nd from a dead stop but that's just my opinion.
2. Since my car is throttle by wire, the computer takes over the throttle and is manipulating it to soften the shifts but sometimes to a fault.
3. By "laying down" I mean that when I roll into the throttle, the engine bogs somewhat and takes time to recover - maybe not quite like a carb with a bad accelerator pump but still sluggish -especially for fuel injection.
4. Yep - anything to increase mileage.
5. Sometimes I will put the car in S mode when pulling out from a stop, but the other day I tried it merging into traffic and the car still short shifted.
6. The stepping issue is very strange.

I've ridden in a car with a CVT (Nissan) and didn't like it either as a passenger. I'm sure it would bother me even more driving it.

Mike,

I may try looking at the throttle body and see if it looks dirty or if something is affecting its operation.

Gruntguru,

The car does seem to like being driven harder and S mode does seem to help except in the case I mentioned about it short shifting.

It would be interesting to put the car on a chassis dyno to see if a plot could visually show some of these strange issues. Either way, at times it makes me miss an American V8 with a 4bbl and manual transmission. I had full control over it.

Kyle

 

[BrianPetersen]

Have you tried test-driving a different car with the same powertrain?

In the old days I'd be suspecting that your transmission was not getting the correct engine-load-sensing signal (be it vacuum or a cable) but nowadays the engine and transmission are connected through the computer system which ought to know (and indicate via fault codes and malfunction warning lamp) if there is an actual problem.

It's possible that the transmission has fault codes stored but the "check engine" lamp is not lit because the fault is not emissions-related. If you have access to a scan tool, scan the transmission controller and see what it says. I don't know if you need a Honda-specific scan tool to get codes like that. (I know you need a VW-specific one to do that on a VW ...)

The only automatic transmission in my household is a hoary old Chrysler 62TE, and it acts better than what you describe.

 

[kjoiner]

Hi Brian,

I'll see if they have one on the lot the next time I go in for service. I might try one of the 2016 models as well to see if there is any difference. One bright spot is that I mention this issues every time I go in so if the transmission fails, I've got a history to use for leverage.

Kyle

 

[BrianPetersen]

Make sure the one you test drive has the regular auto-box and not the CVT.

 

[kjoiner]

Hi Brian,

The V6 models have the 6 speed auto. The inline 4 models such as the Accord Sport have the CVT. Interestingly, the Sport with CVT has paddle shifters.

I really wish the would put paddle shifters or a bump shifter (like on older Acura TLs) on the Accords. That would give you some measure of control over shift points, but I figure that would affect gas mileage.

I hope they never put a CVT on the V6 Accords.

Kyle