accelerator problems

You should try to get a video of this, capturing as much information as possible (eg speedometer, or Scangauge if you have one, whatever else you might be able to get in). I especially don't know anybody that's reported that the engine runs fast before.

Many have posted about the feeling of acceleration, however Bob Wilson strapped an accelerometer to his car, and found that even though it feels like it's accelerating, it's really just a loss of brake power due to the rough surface. (There are many systems - VSC, ABS, traction control - that are designed not to help you brake quickly, but rather to maintain your control over the car. When these systems activate, it can actually increase your braking distance, however because you can still steer and have the car go where you want it to, it's considered safer in most cases.) Others have reported that pressing harder on the brake can counteract this problem.

Personally, I've never experienced it, so I have no idea. In any case, even if there were a defect, it seems to be rare enough that I'm more worried about all the other drivers around me than the car itself.

 

I'm still wondering if you are just thinking the car took off or hit the wrong pedal.
But i don't know. I am not going to attack you just make sure your safe.

Make sure you know how to get the car into neutral. You hold the shifter in the N position until it shifts into N, try it in a parking lot so you get the feel for how long it takes. If you just bump it into N it wont change you need to hold it. I have heard the if your going 10mph or more you can hit the park button and the car will shift to N also, I haven't tried this as i have a hard time hitting the park button while i'm driving. Third you can press and hold the power button down untill the car shuts off, you have to hold it down for at least 3 seconds i think, you can't just tap it.

Also my car brake peddle over rides the gas pedal, so the computer should not allow the ICE to power the car if the brake pedal is pushed. You can try this in a parking lot too, take off how ever you want and keep your foot on the gas pedal and press the brake hard with your other foot deppending on what screen you have on you can even see the ICE stop powering the wheels.

 

You may not notice the tyres slip, doesn't mean they didn't. I don't know what the threshold is, but if one tyre goes in a pothole that is enough to trigger it.

RPM increase is strange, though if you're braking already the engine should be off. So maybe your engine -started- (which makes sense, if it has stopped MG2 torque output the ICE needs to start outputting torque) which might have startled you. However, i can't see why the engine would already be running, or why it would start, unless you were requesting power, which can only happen if you have your foot on the accelrator or hit the cruise control resume (or are maybe still in cruise control).

If you can reporduce this willingly we would all -love- to see a video, since no one has been able to capture a car acelerating/speeding up.

 

What was your State of Charge when or right before this happened? I'm curious if you happened to experience a "battery power bleed" at the same time you were trying to brake. This could easily happen in some areas I drive regulalry but there are not bumps in these sections of roads so it's never happened to me. The result would be 3000+ RPM but no acceleration, just the usual reduction in braking force but coupled with the sound of the engine racing. That is enough to trick the brain into thinking you are accelerating.

http://priuschat.com/forums/gen-ii-...936-engine-rpm-high-car-not-accelerating.html

I'm not saying what you are reporting is wrong. I seriously hope you are wrong though. Otherwise your car is definitely unsafe.

 

State of Charge was high in both cases? That would be a rare situation but if there were enough hills before the location then you could be regenerating a lot of energy. *shrug*

 

"and while slowing down ran over a little uneven pavement(patch job) and my car tried to TAKE OFF!"

"Actually I did not experience any slip at all from the rough pavement."

I know you think it had nothing to do with rough pavement in your later post, but it sounds like it did from how you described it initially. I'm not at all saying you're lying, please don't take it that way, but I know from documenting a LOT about my driving in blog posts that I simply can't remember each little detail, even in the most vivid moments, and sometimes find my mind "filling in the blank" with slight inaccuracies. It can be accentuated in sort of adrenaline pumping cases (remember those surveys after 9/11? Everyone "remembered" seeing the first plane hitting the tower). The RPM thing is questionable not because you're saying it, again, not saying you're writing something untrue, but it's so easily perceived with the sensation of "speeding".

Given the frequency of the regen-to-friction complaint, and my personal experience feeling it, it sounds exactly like traction control/regen to friction transition, and I do hope that it's all it is. I know your 2004 never did it, but the issue seems to be more pronounced in the Gen III.

The one time this really happened to me (I was on black ice and apparently was going too fast for friction brakes at the transition point) if someone asked me if my engine revved after the fact, I very may well have said that it did, cause the sensation I got from the car matched my knowledge and experience of what would have happened if the engine had revved up. There are also other bells and whistles complicating the whole thing, since in this situation your traction light would have come on, you hear the buzzing of the brake accumulator pump, and even with a Scangauge, you'd be so concentrated on the road to even notice if the RPM was high up for a second.

To sum up, do get it checked out, but I actually wouldn't be too worried about it. Since you said it's never happened before, it's probably just the first time you've felt the normal regen to friction thing. It happened twice because it did - sometimes braking over bumps I get it, sometimes I don't. You can avoid the sensation by slowing down a little earlier, then letting up briefly when you see you're about to hit the rough patch, and continue braking after.

Of course, you can also brake beforehand and just know that there will be less deceleration for a certain point and will feel like acceleration. Ever since it happened on the ice, I give myself more room when braking behind other cars, which helps me feel safer even though a similar skid obviously won't happen on dry pavement. It ended up being a good thing to experience.

Best of luck, keep us updated after you get it checked out (or try my suggestions to likely avoid the sensation altogether!).

 

Really short answer: you skidded. Next time go a little slower. Six years of other people's experience shows that anything else you do trying to fix this problem will be a waste of your time.

 

Yes, there was a recall action on that where they reprogrammed the computer. Unfortunately I still see it happening if I hit a pothole or am braking going over railroad tracks. Use EXTREME caution as Toyota pretends this isn't happening and you will have to learn to live (or die) with it.

 

The recall reduced the delay for brakes to reengage after loss of traction during braking. This effect is exacerbated by regenerative braking, but not limited to it. It is an artifact of the ABS system. The only way to keep it from happening is to avoid the loss of traction.

Tom

 

Who are you talking to?

If you're referring to PriusRoadWarrior's post, I'm 90% sure, he's referring to SSC-A0B. Two places to read more about it:
FAQs on the 2010 Prius Recall | PriusChat
2010 Toyota Prius ABS Brake Recall in Less Than a Minute | PriusChat

Your info indicates you have a 2011 Prius. If so, you already have the updated firmware. They made a running production change in January 2010 to use this updated firmware. All vehicles after that point will already have it.

 

It happens to all Prius when the wheels lose traction. It's well documented on this site. It's not broken or dangerous, it's just how it works.

Tom

 

It's funny how we all say it happened to us and we understand what is going on. But the OP is only interested in the one person that says "die" in thier post. LOL

 

My wife and I joke about posts like these. When I hit a pothole while braking, I say to my wife "OH MYGOD! Did you feel that? We could have been killed!", and then we laugh. It's such a tempest in a teapot.

Tom

 

Well, I was actually killed by this very problem!
Thankfully I got better!

 

Re: accelerator problems part 2

You aren't crazy. You are just being fooled by your senses. Humans perceive a reduction in braking force as acceleration or speeding up. It really doesn't happen, but it *feels* like it happens.

Loss of braking, or a reduction in braking, is well documented. It happens when a loss of traction forces a switch to ABS friction braking. Keep pressing the brake and all will be good.

Tom