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-   -   Engine acceleration when braking (https://www.bimmerfest.com/forums/showthread.php?t=631531)

maverick2015 03-02-2015 07:53 AM

Quote:

Originally Posted by zlinda (Post 8939673)
I know I'm not the only one who has experienced this now that I have read through these and other posts. It is unfortunate that the SA said he believes this is how the car was engineered and that it is "normal". It has been reviewed by the Regional BMW representative twice and still nothing found wrong.

If a car lurching/hopping forward is "normal" and I've had it in for every test possible and had multiple parts replaced, reprogrammed, etc. and the problem is still there, am I supposed to accept it and just take it as part of owning the car? If so, Is that a reasonable request? What options do I have?

Hmm - lurching and hoping forward like a strong idle? Hondas and Acuras will pull a few MPH in idle and do this 24/7. In that respect, it sounds more normal than a problem. Also, consider how you have left the car in Park. Sometimes, if I park it and the car is still in motion - the brakes hold the vehicle before it comes to its final rest. This happens often to me depending on how the car is parked, incline/decline, or if the car was rocking back and forth, once you release the brake the car will abruptly roll into its neutral position.

Have you reset the shift logic?

What happened to me was in drive going 25 mph eyeballing the car rev/accelerate itself watching the tach climb.

zlinda 03-02-2015 08:05 AM

It only happens after the car has been off. When I initially get in and start the car with my foot on the brake, I then will move it from "P" to "D". As I release my foot from the brake it will jump forward. If I put my foot back on the brake to keep it from jumping it will die. If I don't put my foot on the brake (if there is nothing in front of me that I'm going to hit) it will eventually "fall" into place and smooth out.

It has been in service several times with certified BMW mechanics at the dealership. I am not sure if they reset the shift logic although I know it has been reprogrammed many times.

maverick2015 03-02-2015 08:14 AM

Quote:

Originally Posted by zlinda (Post 8939711)
It only happens after the car has been off. When I initially get in and start the car with my foot on the brake, I then will move it from "P" to "D". As I release my foot from the brake it will jump forward. If I put my foot back on the brake to keep it from jumping it will die. If I don't put my foot on the brake (if there is nothing in front of me that I'm going to hit) it will eventually "fall" into place and smooth out.

It has been in service several times with certified BMW mechanics at the dealership. I am not sure if they reset the shift logic although I know it has been reprogrammed many times.

What you are describing does not seem that problematic unless it is so jarring and fast that it might be a safety issue for you. I know I have had this happen to me several times turning the car off in Park, and then experiencing what I described in my last post. I think all cars do this at some point. I know that might not be much help.

The X Men 03-02-2015 12:14 PM

zlinda, all cars do not lurch forward when shifting from park to drive despite of what maverick2015 tells you. Sounds like you have a very serious problem. Try to record a video to show the dealer what is happening. If your X6 is fairly new, I would threaten BMW USA with a lemon law lawyer. What is your engine idle RPM speed when your car lurch forward?

Me530 03-02-2015 01:10 PM

Quote:

Originally Posted by zlinda (Post 8939711)
It only happens after the car has been off. When I initially get in and start the car with my foot on the brake, I then will move it from "P" to "D". As I release my foot from the brake it will jump forward. If I put my foot back on the brake to keep it from jumping it will die. If I don't put my foot on the brake (if there is nothing in front of me that I'm going to hit) it will eventually "fall" into place and smooth out.

It has been in service several times with certified BMW mechanics at the dealership. I am not sure if they reset the shift logic although I know it has been reprogrammed many times.

It sounds to me like there is leftover torque that is surging when you go to D. Maybe your torque converter isn't locking up/releasing properly. That's very weird. Try a different service department.

MoshingMomma 03-02-2015 03:38 PM

Quote:

Originally Posted by knoxvolgirl (Post 6937190)
I just purchased a beautiful 2013 silver x3 35i m sport last weekend. It's gorgeous. It now has about 140 miles on it. Twice when breaking slowly (in a parting lot) to stop, the car/engine has continued to try to accelerate. To the point I was basically standing on the break and it was still creeping forward. The first time, to avoid crashing into the building in front to me, I punched the start/stop button to turn the car off. The second time, the car moved forward to where I had to pull into traffic quite dangerously. The floor mat was not obstructing the gas pedal etc. so that's not an issue. The dealer now has it back to investigate. Any thoughts? Never experienced anything like this before. Thanks.


Bring it back.
Don't drive it.
It is a hazard. You are risking your life and everyone else's by driving it.
The dealer will tell you there's nothing wrong.
My X3 was totally written off after an episode of unintended acceleration.
See this forum for my posts and pics.

zlinda 03-05-2015 02:09 PM

Quote:

Originally Posted by The X Men (Post 8940201)
zlinda, all cars do not lurch forward when shifting from park to drive despite of what maverick2015 tells you. Sounds like you have a very serious problem. Try to record a video to show the dealer what is happening. If your X6 is fairly new, I would threaten BMW USA with a lemon law lawyer. What is your engine idle RPM speed when your car lurch forward?

It's very disconcerting when it occurs and happens too fast and unexpectedly to video it would be impossible without starting the video before I start it every time. It revs enough to make the car die if you engage the brake. I've never watched the rpm while it's doing it but that is a good point to try and catch it if I can. It's been in and out of the shop since December. It is a little over 2 years old and is close to the 50,000 mile mark so I'm not driving it until I get this resolved. When the engine malfunctions, it makes the car very difficult to control (similar to the "park to drive" but much more aggressive.

The X Men 03-06-2015 05:45 AM

Quote:

Originally Posted by zlinda (Post 8947113)
It's very disconcerting when it occurs and happens too fast and unexpectedly to video it would be impossible without starting the video before I start it every time. It revs enough to make the car die if you engage the brake. I've never watched the rpm while it's doing it but that is a good point to try and catch it if I can. It's been in and out of the shop since December. It is a little over 2 years old and is close to the 50,000 mile mark so I'm not driving it until I get this resolved. When the engine malfunctions, it makes the car very difficult to control (similar to the "park to drive" but much more aggressive.

If your car is almost out of warranty, make sure you get this problem documented in the dealer's invoice or better yet, open up a complaint with BMW USA just in case the problem still exist after your warranty runs out. Intermittent problems are very hard to troubleshoot, unless the dealer can duplicate the problem repeatedly, they would be just trying to guess what part can possibly cause this problem. Most car manufacturers do not like to throw parts at a car to troubleshoot problems, it is simply not cost effective.

bimmer320ci 03-23-2015 10:34 PM

sounds like could be from doggy brakes air pockets/abs not locking brakes properly if pedal stronger now may be why car could still drive?:)

ANNISSA 04-01-2016 11:19 PM

In Drive with foot on brake and crashed into another car
 
Tonight I was parked at the edge of my driveway, I do not typically drive this car and have another topless car, but that top couldn't work due to the mechanic not finishing a window replacement, told me to not use the top until I bring it back (the window was fixed)

I drove front out from my long driveway, stopped at the edge to open the hardtop. HAD FOOT ON BRAKE, I heard clicking and then the car accelerated while my foot was pressed to the floor on the brake. The car left skids marks until it hit my neighbor's car across the street. When my brain tells me my foot is on the brake and the car is going forward against the brakes, within seconds I hit my neighbors car. If that car wasn't there I would have hit their house. I should have pulled on the emergency brake? slammed it into park? It happened so quickly!

THE CAR ACCELERATED ON ITS OWN WITH MY FOOT ON THE BRAKE!!

Yes, something switched this to happen with trying to open the top and an override took place to make the car accelerate against the brakes being pushed to the floor!!!

ANNISSA 04-01-2016 11:20 PM

In Drive with foot on brake and crashed into another car
 
Tonight I was parked at the edge of my driveway, I do not typically drive this car and have another topless car, but that top couldn't work due to the mechanic not finishing a window replacement, told me to not use the top until I bring it back (the window was fixed)

I drove front out from my long driveway, stopped at the edge to open the hardtop. HAD FOOT ON BRAKE, I heard clicking and then the car accelerated while my foot was pressed to the floor on the brake. The car left skids marks until it hit my neighbor's car across the street. When my brain tells me my foot is on the brake and the car is going forward against the brakes, within seconds I hit my neighbors car. If that car wasn't there I would have hit their house. I should have pulled on the emergency brake? slammed it into park? It happened so quickly!

THE CAR ACCELERATED ON ITS OWN WITH MY FOOT ON THE BRAKE!!

Yes, something switched this to happen with trying to open the top and an override took place to make the car accelerate against the brakes being pushed to the floor!!!:cry:

e46i3x1driver 10-07-2016 03:00 PM

Video of my mom's X1 Sudden Acceleration/Braking Malfunction
 
Here is a link to a video of my mom's X1 that had sudden acceleration/braking malfunction. She was trying to park her car and it flew forward as she was braking. In her panic to stop the car from going even more forward (where there were people), she put the car in reverse. It flew backwards into parked cars. Again, in her panicked state, she put the car in drive and it flew forward. You can see that the car moved at great speed in each direction. At the end, she was swerving to keep the car under control. (She's since learned that if it does it again, to just turn it off or put it in neutral. But you can't blame her for panicking in this situation.)
She says she had her foot on the brake the whole time. She kept saying, "I was braking and it just wouldn't stop! It just wouldn't stop!" The car hit the wall and the parked cars so hard it suffered frame damage.
Her size 5 feet are tiny and narrow and she would not be able to step on both the accelerator and brake pedals at the same time. There also was no floor mat as she doesn't like them.
If she had her foot mashed on the accelerator, she wouldn't have been able to change gears from Drive to Reverse to Drive because the revs would've been too high.
And driver error in one direction is plausible, but in forward, reverse, then forward again? That's a bit hard to swallow....
BMW did an investigation and of course found nothing wrong.
Since we got the car back from their "investigation", we noticed that the car is much smoother than before. It was always a bit jumpy since it was new; that jumpiness is gone - could just be us but the car does feel different.
My mom is terrified to drive the car again but she has no choice.

https://youtu.be/SEM7bVQ6lis
Copy and paste if the embedded video doesn't work for you: "youtu.be/SEM7bVQ6lis" _sl_

chomputer 10-09-2016 04:32 PM

Quote:

Originally Posted by e46i3x1driver (Post 9869936)
Here is a link to a video of my mom's X1 that had sudden acceleration/braking malfunction. She was trying to park her car and it flew forward as she was braking. In her panic to stop the car from going even more forward (where there were people), she put the car in reverse. It flew backwards into parked cars. Again, in her panicked state, she put the car in drive and it flew forward. You can see that the car moved at great speed in each direction. At the end, she was swerving to keep the car under control. (She's since learned that if it does it again, to just turn it off or put it in neutral. But you can't blame her for panicking in this situation.)...

That explanation and the video evidence don't add up. So many things would have to fail all at once for this story to be true.

Note that the brake lights do not light up throughout. This means that at the same time:

1. The simple brake light switch that pops out when the brake pedal is pushed down fails, so the brake lights don't activate.

2. The braking system itself also failed because the brakes can easily overpower the output of the engine.

3. The throttle also had a catastrophic failure and caused the car to accelerate on its own, not just a little bit, but at full throttle.

It's much more likely that the driver thought they were mashing the brake pedal, but was actually mashing the accelerator instead. That literally explains everything you see in the video.

Quote:

If she had her foot mashed on the accelerator, she wouldn't have been able to change gears from Drive to Reverse to Drive because the revs would've been too high.
Wouldn't this be the case both for a malfunction and for an operator error?

Would be interesting to know other details surrounding this incident. Did anyone in the parking lot get hurt? Does driver's insurance limits cover damage to all those cars that she hit/injuries that she caused or is she looking at a major financial catastrophe and needs to shift blame to BMW? (Don't skimp on your liability limits and buy an umbrella policy if you don't have one people!) Is the driver emotionally unstable? History of road rage, going through major emotional crisis that might make them snap?

Benefit of the doubt, driver just made a mistake and sincerely believes their vehicle malfunctioned, but looking at the video this is 99.9999% caused by operator error.

missedbass 10-09-2016 05:52 PM

I hope your braking problem has been resolved and I hope you enjoy your X3. However, I don't have a doctorate after my name but I do know the difference between braking and breaking. LOL

e46i3x1driver 10-09-2016 05:55 PM

You know, I also first thought it was my mom's error, that she mistook the gas for the brake or some other kind of driver error. But after she talked me through what happened, the way she explained things right after it happened when things were still raw and memory was fresh, I believe that something malfunctioned on the car.

My mom is a 67 year old woman who drives carefully and has no tickets or accidents on her record for more than 40 years. In the 42 years I've known her, she's never exhibited any type of behavior that would lead to road rage or "snapping" - she's just not the type. She's emotionally stable and has no history of road rage. She was parking so she can do her daily laps at the gym pool - she's in great shape and it's somewhere she goes to and parks at every day. My mom drives a lot, putting over 30k miles on the X1 in the past 2 years.

If it was a case of road rage, the way she entered the parking lot and drove to her parking spot was calm. And after she was able to regain control of the car (when it looks like she's leaving the parking lot), she immediately returned to the scene of the accident and she called 911 to summon local police help. She was very shaken up.

She said that she could not stop the car, that the car kept moving even though she was depressing the brake pedal. Maybe that's why we don't see brake lights - because the brakes didn't work.

I can understand making some kind of mistake (stepping on the gas instead of the brake) in one direction but to do it 2 more times - which would mean, foot mistakenly on the accelerator, hit something, foot off the accelerator, change gear to reverse, foot back on the accelerator (and not just tapping but mashing since we see the car fly backwards), hit something, foot off the accelerator, change gear to drive, foot back on the accelerator (again mashed on it) to the point that it's swerving to maintain control - that's a bit much.

Funny, you sound exactly like the BMW investigator who also said word for word: "brakes can easily overpower the output of the engine".

Her insurance took care of everything so there is/was no need to shift blame to BMW.
But looking at previous posts on the thread, it looks as if there may be some kind of malfunction that has happened to more than just my mom.

The X Men 10-11-2016 06:12 AM

It looks like she never hit the brakes, she hit the gas instead. It happens to the best of us, instance like this among elderlies are common in parking lots. The reason she was able to change gear is because came to a stop after hitting the other cars. The brake pedal is program to override the gas when depressed.

dukedkt442 10-11-2016 06:09 PM

Back in the '80s Audi almost went under because of unintended acceleration issues. Turns out, the Germans had their pedals moved slightly to the left, so that Americans were often hitting the accelerator thinking it was the brake. Time and time again, an overwhelming majority (if not all) of unintended acceleration cases have been due to driver errors, but drivers always say "not me no way!"

Couple years ago, an old couple attempted to back out of a spot on the pier but instead drove off. Their jeep was found in drive.

Last winter I got hit while walking across a cross walk. The old bag that hit me hit the gas instead of the brake.

Every time my car is accelerated on it's own has been due to a floor mat getting under the pedal and holding it down after I've floored it. Reached down and removed it no big deal.

RickyBlueE46 12-17-2016 05:02 AM

I am having the same issue, I fairly certain it's due to a "VACUUM LEAK" and NOT "DRIVER ERROR" or "FLOOR MATS"!! The vacuum system is ridiculously complicated in these cars and the majority of hoses which are either rubber or crappy plastic pieces... And they are all linked together. Intake, Oil dipstick, crankcase ventilation valve and the brake booster vacuum. I fixed mine from stalling with a hose clamp around the intake manifold vacuum line, and now when I apply the brakes the engine surges. It's a work in progress.. hopefully this helps

AVI8HISTORY 12-17-2016 06:13 AM

Quote:

Originally Posted by knoxvolgirl (Post 6937190)
I just purchased a beautiful 2013 silver x3 35i m sport last weekend. It's gorgeous. It now has about 140 miles on it. Twice when breaking slowly (in a parting lot) to stop, the car/engine has continued to try to accelerate. To the point I was basically standing on the break and it was still creeping forward. The first time, to avoid crashing into the building in front to me, I punched the start/stop button to turn the car off. The second time, the car moved forward to where I had to pull into traffic quite dangerously. The floor mat was not obstructing the gas pedal etc. so that's not an issue. The dealer now has it back to investigate. Any thoughts? Never experienced anything like this before. Thanks.

Everyone should know what to do in this situation - just push the gear shifter to the neutral position. DO NOT turn off the ignition as you loose power steering among other things.

Practice it in a large parking lot to make sure you know how to shift to neutral. I can't believe the number of people who do not know that you can shift a car with automatic to neutral while moving. A relative totalled a new CR-V into a telephone pole because she did not know this and instead was standing on the brake peddle until the car ran off the road and into the pole. While it may be that your car does have a mechanical issue many of these sudden acceleration situations or what you describe turn out to be operator error (read panic).

With winter boots on (size 13 feet), I once realized that when trying to stop while maneuvering to park I also had my foot partly on the accelerator and almost broadsided a very nice Corvette. As soon as I heard the RPM go up, I realized what was happening and hit the brake peddle with my left foot while lifting off with my right. Lesson learned, watch the feet placement!

insound 06-01-2017 11:58 AM

128i 2013 19,000 miles - 3 incidences of unintended acceleration. All at less than 15 mph while breaking to stop. Left foot on break. No foot on accelerator. Car sped up after first slowing down. No rug.gas pedal interference. Very scary/adrenaline rush. so far, no damage. BMW dealer says they can't find any problem nor do they know anything about this problem occurring in other BMW;s. Does someone have to die before BMW steps up to the plate and addresses this problem that plagues the industry? Other than that intermittent problem this is the best handling and most fun to drive BMW I have (BMW driver sine 2003) owned. Really hope BMW can nail this bug and give us back the confidence we once had in out BMW. As is, we're afraid to drive it.

lbjgh 06-01-2017 09:03 PM

If you are driving with your left foot on the brake you don't know how to drive.

Le Chef 06-02-2017 07:41 AM

Bollocks!
 
Quote:

Originally Posted by lbjgh (Post 10182585)
If you are driving with your left foot on the brake you don't know how to drive.

Race and rally drivers left foot brake all the time - it gives you better control. But and it's a big but most people do not have the muscle memory capability to be sensitive enough with their left foot to be able to brake properly.

Doug Huffman 06-02-2017 10:27 AM

Quote:

Originally Posted by lbjgh (Post 10182585)
If you are driving with your left foot on the brake you don't know how to drive.

That is an ignorant statement.

SCCA SS-C Class SAAB 99 Champion driver Don Knowles taught how to use the whole Kamm Traction Circle by braking AND accelerating simultaneously. It was entertaining to watch him pull away from the pack in a corner, brake lights on, inside rear tire smoking stopped, but perfectly balanced over/understeer.

insound 06-02-2017 11:44 AM

i used to play a drum set so coordinating my left and right feet has never been a problem: and never an accident (fingers crossed).

farg 06-02-2017 01:25 PM

I see above that many trained race drivers use the left foot for braking. I guess Heel and toe went out with the manual transmission? I tend to agree that left foot braking on the road is not the norm, and seems out of place unless on the track.
What happens if you get into a manual transmission car, and you've got left foot braking muscle memory? Heel and toe the clutch? :p


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