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Discussion Starter · #1 ·
Hello, all.

I have a 2014 Touring and I have noticed that periodically, the car will shudder under acceleration. It particularly is noticeable when moderately accelerating in the 3000-4500 RPM range (not stepping into the kickdown switch, but at 80% throttle or so).

It can be felt mostly in the gas pedal and generally in the vehicle itself (the wheel doesn't wobble). It almost seems like the engine is quickly surging.

It does not do it every day, and I have not found any pattern to it yet.

Has anyone else experienced this? It is the AT model.
 

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No.

Usually if I had issues like that on older cars it was related to a sensor of some sort or coil packs misfiring. Too new for coil packs I'd think.

Never a bad idea to baby it and go to the dealership while under warranty.
 

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Discussion Starter · #3 ·
No.

Usually if I had issues like that on older cars it was related to a sensor of some sort or coil packs misfiring. Too new for coil packs I'd think.

Never a bad idea to baby it and go to the dealership while under warranty.
Yeah - I've made an appointment with the dealer.

I have narrowed it down to second gear where it's the most noticeable.

I did read a TSB on the Mazda 3 that was related to winter fuels and what was a type of vapor lock when the fuel was fed through the high-pressure fuel pump. The additives would easily turn to vapor under heat and cause stuttering, etc. as the additives help with vaporization to help cold starting, etc. I know there was an ECU update for this.

Since I see it in the 30 degree range, I'm wondering if it's the winter blend gas causing the issue.

I guess we'll know on Thursday as that's when I take it in...
 

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New member! Formerly of the E36 BMW forums - decided to have a car instead of a constantly broken mantlepiece. At least hundreds of hours of taking apart and rebuilding cars could be worth something someday.

Anyways, I got this shudder deal, too. First gear wide open, second gear for the most part, then it dissipates for third, probably hidden under the multiplication of the gear ratios (and resultant frequencies).

Could be engine something-or-other (as mentioned above with the misfire). I was thinking possibly something in the transmission.

I've considered joining the forum to post about this. Ya beat me to it, but inspired me to join regardless.

I'm skeptical about dealers. Often times they stare at you blankly and write what you say down. Later, no one seems to know there was a problem, and it wasn't found. Just never seemed to happen under their control.
 

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I have noticed this in mine as well. I bought it at the end of August though, and we were definitely not using winter blend gas here in Houston then. Though I can't say I have experienced it recently. How many miles have you put on? I noticed it somewhere between 100-1000, and have just over 4000 now. I'm going to try on my way home tonight.

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6,000 miles on the odo, first gear a littler stronger vibration than second, not observable in third under any circumstances. Lots of warranty left, but - I hate stealers (dealers) with a passion and can see how this might play out with the wonderfully trained service staff!

I also noticed it does it at partial throttle, like the OP stated.
 

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Discussion Starter · #7 ·
I'm glad I'm not the only one.

I purchased the car in November. Noticed the issue at around 1000-1500 miles. The car now has 2200 on it. It performs decently when warmed up, although sometimes it's still apparent. I have noticed that it is worse when accelerating on on-ramps (cloverleaf) when there's a turn associated with uphill climb to the highway. I'm guessing it's load related.

Winter blend varies here, but it really came on with the very cold weather here at which point they would have put a ton of additives to help combustion/starting/emissions.

It is noticeable in first to some degree, second is the most prevalent, with all other gears fine.

The tech at the dealership stated that its the 'nature of the beast', although I don't think he was able to duplicate it. He did, however, seem knowledgeable and spoke with me for 10 minutes about the engine/transmission (I'm a tech/car junkie). The transmission shares clutch packs on 2-4-6 and 1-3-5, so if it was a mechanical issue in the transmission, it should show up. Also, he stated that at 7mph the converter goes into full lock-up on acceleration and uses a pre-load on the clutch packs for the next gear to facilitate a small amount of slip in between gears without having to unlock the converter.

No misfire showed up (cars will throw a MIL if they get too prevalent - with this issue, and how it feels, I think it'd throw a code).

At this point, I'm thinking it's gas blend and ECU tuning related to fuel pressure/flow/injector duty cycle. I do know from previous open-source tuning I've done that vehicles will change tables for timing/duty cycle on injectors, etc. based on current gear, load, temperature (intake), etc.

My plan is to pull the positive battery cable and let the ECU clear its learned tables. If the problem goes away, I'm thinking software. If not, then???
 

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Great reply!

In my mind I had pictured the converter lockup maybe not being 100% and giving some kind of pulsating feeling. At it's worst, the shuddering was noticeable by passengers in the vehicle who actually expressed concern something was about to break. It was felt in the steering wheel... not a "sawing" left to right, but a wheel bouncing up and down kinda shake. I wondered that since the shuddering didn't change with RPM then it would be output related. I suppose clutch packs being shared between 2-4-6 means that it should be happening in 4th (unless buried by long multiplication of the final drive ratio), which it doesn't...

A friend had a 94 Lebaron sedan (sad) that would vibrate on acceleration that turned out to be the transmission. This is why I wondered... BUT!

It makes far more sense that this would be fuel/ECU related.

My next tank of fuel I may just swap it out for some premium fuels (Shell comes to mind - lacking ethanol) to see if that makes it go away. Also I will see if your reset makes any changes, and if either solves the problem we're good to go.

I will have to wait until the spring where the fuel blends change to confirm, but as I fuel up later today I should have something to report...!
 

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Discussion Starter · #9 ·
Great reply!

In my mind I had pictured the converter lockup maybe not being 100% and giving some kind of pulsating feeling. At it's worst, the shuddering was noticeable by passengers in the vehicle who actually expressed concern something was about to break. It was felt in the steering wheel... not a "sawing" left to right, but a wheel bouncing up and down kinda shake. I wondered that since the shuddering didn't change with RPM then it would be output related. I suppose clutch packs being shared between 2-4-6 means that it should be happening in 4th (unless buried by long multiplication of the final drive ratio), which it doesn't...

A friend had a 94 Lebaron sedan (sad) that would vibrate on acceleration that turned out to be the transmission. This is why I wondered... BUT!

It makes far more sense that this would be fuel/ECU related.

My next tank of fuel I may just swap it out for some premium fuels (Shell comes to mind - lacking ethanol) to see if that makes it go away. Also I will see if your reset makes any changes, and if either solves the problem we're good to go.

I will have to wait until the spring where the fuel blends change to confirm, but as I fuel up later today I should have something to report...!
Well - I pulled the battery last night and the shudder is gone so far - I'll know more during the upcoming week. If it indeed goes away, then comes back later, my mind tells me that it's a learned table issue (programming) that's simply a drivability concern.

On another note, it was -1F this AM here and the car did something that it did the LAST time it was very cold (which was the first experience for the car in below zero temps) - it would downshift two gears when full throttle was reached (i.e. kickdown switch), but would not put out full power. It felt like the car was down 30 horsepower. The transmission was not slipping.

It will repeat this for the first 10 miles of my 20 mile drive, then be fine from that point on and during future cold events.

This tells me that there possibly is another drivability issue in the factory tables with (maybe) cam timing or fueling based on intake temperature. Once it tweaks the learned tables for *something* it will 'know' what to do from that point on. Since I'm in a heated garage (I keep it at 40F), I don't think it's low tranny temperature, but something based on intake air temperature.

This is the first winter the production vehicles have seen, so hopefully a TSB is released. I really wish mine would throw a damn MIL light so that it would store a code and help things along repair/diagnosis wise. I also wish the technician would datalog the thing and send it to Mazda for review. They would see an anomaly pretty quickly.
 

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On another note, it was -1F this AM here and the car did something that it did the LAST time it was very cold (which was the first experience for the car in below zero temps) - it would downshift two gears when full throttle was reached (i.e. kickdown switch), but would not put out full power. It felt like the car was down 30 horsepower. The transmission was not slipping.
Was the blue cold engine light still lit? The manual says something about the engine limiting itself while it's cold.
 

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Discussion Starter · #11 ·
Was the blue cold engine light still lit? The manual says something about the engine limiting itself while it's cold.
I checked the manual the first time this happened to see if something was in there related to temperature and performance and didn't see anything. I'll look again. The indexes are horrible in vehicle operations manuals.

The blue light was off and had been for about 5 minutes before I needed the car to perform so I didn't get run over by a semi :)
 

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-25.6F last night here... I made a post in a different thread about what the car does in those temps. Different!

I now have premium fuel installed.

The only thing is, I didn't manage to even get the car warmed up to proper operating temperature even after 15 minutes of driving to check for a shudder.

I will wait until it warms up in a few days to give it a go, I guess. Sounds like an ECU/Fuel thing for sure, though...
 

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Discussion Starter · #13 ·
-25.6F last night here... I made a post in a different thread about what the car does in those temps. Different!

I now have premium fuel installed.

The only thing is, I didn't manage to even get the car warmed up to proper operating temperature even after 15 minutes of driving to check for a shudder.

I will wait until it warms up in a few days to give it a go, I guess. Sounds like an ECU/Fuel thing for sure, though...
I took it to the second dealer today. They could not duplicate the issue (I'm not surprised). At least I now have two instances of service visits logged. This tech (and I take quite a bit of this with a grain of salt) stated that if the catalytic converter is not up to temp/efficiency that the engine will limit the engine output until it reaches the proper temperature. I can somewhat 'buy' this as an explanation for the huge dip in power for some time even after the car is 'warm'.

The shudder is a different issue altogether. At this point if enough people experience it, they will release a TSB for it. Until then...... Hell, I noticed the steering wheel wasn't aligned perfectly and didn't give a crap - Mazda had a TSB for that. I'm not too picky about cosmetic issues, but driveability is another story.

It's supposed to be -10F tonight, so we'll see tomorrow on the way to work. Right now, the car is in a 40F garage and it's 0F outside so I do try to keep it above freezing all the time in the garage with the heater.
 

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Discussion Starter · #14 ·
Well - after my ECU reset and subsequent lull in the vibration, it's back. At this point, I'm not sure what to think...

I guess enjoy the days that it doesn't do it and hate the days it does. I sure wish that the dealer could duplicate it.

The last thing I thought of was possibly an engine mount, but I wouldn't thing that would be a sometimes thing...
 

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Bring it to another dealer if you can. Sorry about your issues :/
 

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Well - after my ECU reset and subsequent lull in the vibration, it's back. At this point, I'm not sure what to think...

I guess enjoy the days that it doesn't do it and hate the days it does. I sure wish that the dealer could duplicate it.

The last thing I thought of was possibly an engine mount, but I wouldn't thing that would be a sometimes thing...
I haven't had it since doing the Shell V-Power deal, no ethanol, premium... Give that a try next.

I've only tried to replicate it twice, though. I just can't seem to find the time to drive at the moment. It's pissing me off! Mind you, the roads are all frozen solid and I haven't seen pavement in about a month now.

Bad engine mount will rock back and forth under load and with sudden off loading. The early stages of failure would be random vibrations at idle, and (possibly) vibrations under load, depending on if they're hydraulic or rubber. The old rubber mount in my BMW inline 6 would kick the engine back and forth when going bad, and the hydraulic mount in my VQ Nissan would let the engine vibrations kick through the chassis (after 200,000 miles).

I don't think it could be a mount. I'm going with fuel for now. Just hope that a cylinder isn't leaning out or anything like that.

Second guess would be the trans. If it comes back with premium fuel I'm going straight to the stealer this time...
 

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I'm afraid I'm noticing this too, epically in 2nd and even 3rd gear right about 2500 RPMs...DANG IT
 

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Mine still does it, first, second gears only, premium or regular fuel. We had a minor winter thaw and the car suddenly acted normal for a day.

Then it got cold again (and is seemingly staying ultra-cold forever)... does it all the time now. As for getting it fixed or even checked out at the dealer: The roadways are basically a 3inch thick layer of ice with a bit of sand on top for traction. Very rarely have I been able to find a dry (or even wet) road to even try it on.

It's just... really interesting. I believe at this point it can only be the fuel system, transmission, or a frozen engine mount.
 

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Discussion Starter · #20 ·
I'm still experiencing the issue - especially when it's 10 degrees to 35 degrees out.

I took it to the dealer one more time to get it logged into their system for a third time and the regional service rep from Mazda was there and they were discussing the vehicle. The regional rep stated that they are having quite a few drivability complaints related to this issue in the colder climates - he was unaware of the status with Mazda on a potential fix. Mine does it primarily in 2nd and 3rd gear, but it will sometimes exhibit it in 1st as well, however it gets up in the revs pretty quick and smooths out.
 
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