Engine revving

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2016.5 CX-5 Sport
Hey guys,
I have a 2016.5 cx-5 the other day I started the car, while in park I pressed the brake and the engine temporally revved up then settled down. If I waited a moment or two I was able to replicate the issue. Is this something I need to be concerned about and look into,has anyone else had this happen ? I have seen reports of cx-5's suddenly accelerating and I'm hoping this is not a prelude to that happening.
 

erhayes

Contributor
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Mazda CX-5 FWD Touring
I haven't heard or read anything about CX5 revving under the conditions you state. Give us the reference to the report of sudden acceleration. ed
 
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2019 CX-5 GT 184 2.2 twin turbodiesel auto - Sonic Silver
If you repeatedly press the brake while a gasoline engine is idling on any car you effect the inlet manifold pressure and the revs will go up. There is no fault. I think the runaway revs problem was with Toyota a few years ago and how a driver can let it do that without knocking it into neutral is beyond me.
 
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2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
snip...
If you repeatedly press the brake while a gasoline engine is idling on any car you effect the inlet manifold pressure and the revs will go up. There is no fault.

I'm not saying that you're incorrect but I've been driving for over 45 years and I don't recall ever seeing an increase of engine speed caused just by stepping on the brake peddle.
 
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2019 CX-5 GT 184 2.2 twin turbodiesel auto - Sonic Silver
snip...


I'm not saying that you're incorrect but I've been driving for over 45 years and I don't recall ever seeing an increase of engine speed caused just by stepping on the brake peddle.

Try it. Get it warmed up and then at idle sit and pump the brake pedal.
 
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2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
Try it. Get it warmed up and then at idle sit and pump the brake pedal.

I'll give this a try today when I'm out and about, if I can remember that is.

From the OP's statement, it doesn't sound as if his car was warmed up yet. I'll try it both ways.
 
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2016.5 CX-5 Sport
So since I last posted I have driven the car a couple of days without a problem then yesterday at an ATM with the car in drive and my foot on the brake I was getting a withdrawal when the engine started to race. I put it in park took my foot off the brake and finished the transaction. Then when I put it in drive to leave, the car lurched forward and I heard a loud BANG, really loud like someone hit an empty oil drum with a sledge hammer. I dove it home and it seemed fine,like nothing had happened. I called the dealer and was kind of taken back when he said it would be a week before he could give me an appointment. I know Mazda is not one of the big volume car companies but good grief.
 
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So since I last posted I have driven the car a couple of days without a problem then yesterday at an ATM with the car in drive and my foot on the brake I was getting a withdrawal when the engine started to race. I put it in park took my foot off the brake and finished the transaction. Then when I put it in drive to leave, the car lurched forward and I heard a loud BANG, really loud like someone hit an empty oil drum with a sledge hammer. I dove it home and it seemed fine,like nothing had happened. I called the dealer and was kind of taken back when he said it would be a week before he could give me an appointment. I know Mazda is not one of the big volume car companies but good grief.

Took me 3 weeks to get an appointment from my dealer. I ended up getting new front struts, vacuum pump, and rear brakes and rotors from my local Indy. Since I get free oil changes I will let Mazda do that. Dealer said they were inundated with recalls and service requests.
 
I have a 2018 CX-5 that I have driven for two and half years. In that time I have had three incidents in which the engine unexpectedly over-revved while I was in gear. I quickly shifted into Neutral since it felt like the brakes were slipping. Talk about an adrenaline check! Went directly to the dealership I bought it from and had to make an appt. The results of the appt. were that they could find nothing wrong! I expected something along the lines of a recall problem, but no. All I can say is driver beware.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
I have a 2018 CX-5 that I have driven for two and half years. In that time I have had three incidents in which the engine unexpectedly over-revved while I was in gear. I quickly shifted into Neutral since it felt like the brakes were slipping. Talk about an adrenaline check! Went directly to the dealership I bought it from and had to make an appt. The results of the appt. were that they could find nothing wrong! I expected something along the lines of a recall problem, but no. All I can say is driver beware.
Although I personally have never experienced unintended acceleration, but quickly shift the gear into Neutral with the foot on the brake like you did should be a common knowledge. The power of the brake should be able to withhold the power of the engine, and the brake alone should be enough to stop the unintended acceleration. If you feel it can’t, just shift the gear into Natural.

My question is, in your case, what happened when you shifted the gear into Natural? Did the engine revved to 6,500 rpm or it actually came down to 650 rpm?
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
I have a 2018 CX-5 that I have driven for two and half years. In that time I have had three incidents in which the engine unexpectedly over-revved while I was in gear. I quickly shifted into Neutral since it felt like the brakes were slipping. Talk about an adrenaline check! Went directly to the dealership I bought it from and had to make an appt. The results of the appt. were that they could find nothing wrong! I expected something along the lines of a recall problem, but no. All I can say is driver beware.

What were you doing when the engine "over-revved"? Were you in Park or Drive? If you were in Drive, were you stopped at a light, or were you travelling on a roadway? Was sport mode on? What RPMs did the car jump from/to?

I'm asking these questions because without a little more context, it sounds like it could just be the car downshifting when you weren't expecting it to.

I'm also asking these questions because pretty much every "unintended acceleration" case has been investigated by various parties (including the NHTSA) with no fault/defect found on the vehicle(s), and the "unintended acceleration" was not able to be reproduced in testing.

Either way, knowing that such incidents would be well scrutinized based on the many cases of "unintended acceleration" being proven wrong (and the "black box" data gathered during the investigations), I would take measures to try to capture these incidents on video so that there is more proof. An example would be mounting a dashcam, a camera in the footwell, and a camera pointed at the instrument cluster so that you have video evidence of the unintended acceleration if/when it happens.

It sounds like a lot to do, but again, with the history of this particular issue in the automotive world, the onus is on the driver at this point to prove such an issue exists. My $0.02.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
Could the floor mat be interfering with the brake/accelerator?
That’s the official finding on Toyota’s unintended acceleration case several years ago.. Until today, each time I brought my 2018 Toyota Yaris (Mazda2) to a Toyota dealer for factory included maintenance and warranty service, Toyota dealer will check and remove any additional floor mats which put on top of the factory floor mat on driver side. I personally don’t believe the floor mat would make gas pedal stuck and cause unintended acceleration, at least not on my Yaris.

A friend of ours had experienced unintended acceleration on her newly-bought Lexus RX many years ago. She was able to stop the vehicle on the roadside by her fullest effort with the foot on the brake without shifting the gear into Neutral just like most car ethusastics predicted - brake has more power than engine. She spent a long period of time fighting with Toyota USA to get her new Lexus RX replaced due to the incident. She eventually succeeded.
 
For the record, I love the Mazda CX-5. It is one of the best cars I have ever owned, both foreign and domestic. To answer sm1ke, the latest incident occurred while I was stopped at a stop sign and the gear shift was in Drive. Sport mode was not on. I had just pulled out of a parking space and had been driving about 5-6 mph. In my estimation the over-revving was not a case of the vehicle performing normally , although as I said it only happened 3 times in a two and half year period. I believe there is a flaw or a malfunction of some kind somewhere, unless someone was able to hack the vehicle. As for the floor mat theory, the folks at the Mazda dealership asked me the same thing. That idea was quickly ruled out after they inspected the vehicle.

Whatever the cause, the only reason I related my experience was to satisfy my curiosity about what other Mazda owners may have learned that would be helpful in understanding the issue. As for the earlier events where the engine over-revved, they happened too long ago to remember the particulars. Thanks for your replies.
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
For the record, I love the Mazda CX-5. It is one of the best cars I have ever owned, both foreign and domestic. To answer sm1ke, the latest incident occurred while I was stopped at a stop sign and the gear shift was in Drive. Sport mode was not on. I had just pulled out of a parking space and had been driving about 5-6 mph. In my estimation the over-revving was not a case of the vehicle performing normally , although as I said it only happened 3 times in a two and half year period. I believe there is a flaw or a malfunction of some kind somewhere, unless someone was able to hack the vehicle. As for the floor mat theory, the folks at the Mazda dealership asked me the same thing. That idea was quickly ruled out after they inspected the vehicle.

Whatever the cause, the only reason I related my experience was to satisfy my curiosity about what other Mazda owners may have learned that would be helpful in understanding the issue. As for the earlier events where the engine over-revved, they happened too long ago to remember the particulars. Thanks for your replies.

During the latest incident, do you remember how high the revs jumped? You mentioned that it felt like the brakes were slipping.. does that mean the over-revving happened as you were slowing for the stop sign? How cold was it outside at the time?

Apologies for all the questions, but asking questions and gathering information is important in determining if there are some common factors that may cause the issue to occur. It seems that the OP from 2018 disappeared from the site at the end of May 2018, so we never got a resolution or any more information.
 
No problem with asking questions. I would guess, from the sound the engine was making, that it was red-lining. Yes, I was slowing down for the stop sign and came to a complete stop by the time the engine finished racing. It felt like the brakes wouldn't hold the car back from entering the intersection, which is why I shifted into Neutral. The temperature outside was in the low to mid 30's.

I can't think of any relevant patterns with these events as they have been so infrequent. But I appreciate your questions as I will pay more attention to the exact circumstances should this occur again.
 
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