All are hydraulic.

 

assuming youre talking about cvt otherwise how would you heel/toe

 

The throttle disengagement occurs after a few seconds of simultaneous engagement. A heel/toe operation takes a fraction of a second.

 

The phone call was made by his wife. Toyota didn't really take it seriously until this incident. The CHP officer is a 20 yr veteran. At the moment they don't know if he slid the shifter to Neutral or not. Toyota has had more than 2000 complaints of unintended acceleration in the last decade. They've put it off because 2000 cases in 10 years is a drop in the bucket.

http://www.signonsandiego.com/news/2...&zIndex=163775

You're more mechanically inclined than most folks. The idea of safety design is that the ordinary Joe/Jane doesn't have to figure it out. This is why the Germans have led the way in safety features like ABS brake, ESP (electronic stability control), EBD (electronic brake distribution), shift-lock mechanism, and throttle kill upon hard braking. One doesn't need to figure it out; they're just there waiting to kick in. Yet that never stops the Germans from having 100+ cars pile-up.

Toyota Venza as tested by Consumer Reports...

http://abcnews.go.com/video/playerIndex?id=8980024

 

Fact.........you CAN stop or slow down the car simply by slamming on the brakes.

Not sure where you were going with the whole 100 car pile-up thing....accidents happen.

I didn't say the driver had called, just that there was enough time between the problem presenting itself and the unfortunate end for a call to be made. Long enough in my opinion for a vehicle safety officer to determine the safest way to stop his car.

 

I guess I misread your English when you wrote:

"He had enough time for a phone call. Doesn't say much for his training."

Just watch the Consumer Report video regarding the Venza...

http://abcnews.go.com/video/playerIndex?id=8980024

The Venza's brakes weren't powerful enough. Most drivers' instinct is to pump the brake, which in this case caused the Venza's power brake to become less effective.... hard pedal action but ineffective in slowing down the car.

I take it anything else that doesn't concur with *your* fact isn't fact.

Yes... accidents happen. Some caused by drivers others by the way the car was designed.

 

I have had a chance to see the video. Nice creative editing. You did notice that as he was pressing the brake pedal that the car was actually slowing down. He then went on to say that pumping the brakes would cause them to basically stop working. He never stated or demonstrated that by holding the pedal down you would not be able to slow down.

 

I'm aware of that part and it could be CR's assumption that people still pump the brake when they feel the car is not slowing down fast enough. It's something Toyota who has to take up with CR if they felt the Venza was inaccurately portrayed.

However, your POV is that everyone knows NOT to pump the brake in an emergency situation is YOUR assumption. We are not a nation of pilots and racecar drivers.

My opinion is that if a car's brain (ECU, ECM) doesn't have the feature whereby the fuel is immediately cut off when the brake pedal is depressed hard, the stopping distance is naturally increased. At intersections, off-ramps, stop signs, avoiding an accident might be difficult.

 

Odd... when ABS didn't exist, only the expert drivers knew to pump brakes on icy surfaces. Now only the experts know NOT to pump brakes? I don't buy that argument.

 

lhoboy,

I think you mistook pumping/pulsating the older (ABS-less) brake "on icy surface" as a way to prevent wheel lock-up or skid... as opposed to pumping the brake (in the attempt) to get more braking power.

 

Except in the case of air in the brakelines, when would pumping the brakes ever provide more braking force? Has anyone, expert or novice ever believed that?

 

What percentage of car owners today actually have their brake fluid flushed on a regular basis? Have you not heard of cases where car owners who haven't had the fluid flushed in years and complain of spongy brake pedal even with new pads?

When piston seals at wheel calipers/cylinders and master cylinder get scored, what happens? When moisture/water is absorbed into the brake fluid, what happens? They deteriorate the performance of the brake system. Pressure is lost through the seals and moisture-soaked fluid becomes more compressible. Repetitive pumping of the brake is a way to build up pressure/force on the brake calipers/cylinders.

 

Even with spongy brakes, pumping the brakes can only help if the pedal goes all the way to the floor the first time you depress it.

 

The vast majority of gas-engined cars and trucks use vacuum-assisted power brakes. The vacuum for the power assist comes from the intake manifold during closed or light throttle operation, the booster is designed to 'accumulate' enough vacuum to be effective for two or three pedal applications if the engine is not running, after that, assist is lost but braking is fully available at much higher pedal effort. In cases of runaway acceleration due to a stuck throttle, jammed pedal or other fault, the engine no loger is developing any manifold vacuum, and if the driver hits/releases the brake more than a couple times, the brake will feel as if it's failed. If you are not prepared for this, you'll feel that the car is running away out of control. Simply push as hard as humanly possible on the brake and the car will stop. If you are fighting against a runaway engine, this will add probably hundreds of feet to your stopping distance. If you have a manual trans, push the clutch in, with an automatic, pop it in neutral. The engine might sound like it's about to come apart, but all modern engines are equipped with rev limiters that keep the RPMs out of damaging levels.

Power brakes usually need about 20 pounds of pedal pressure for an average stop, usually no more than 30 or 40 for a panic stop. Without power assist, the pedal effort is often more than 50 pounds, with 100 pounds needed for a panic stop. Most if not all people are capable of that much force, if you are able to stand on one leg, you are set. You just have to be prepared for it. It's always a good idea to get a feel for how your car works without power assist. You can try this on a hill devoid of traffic. Stop the car facing downhill, shut off the engine. Pump the brake pedal 4-5 times to use up the boost, then pop the car in neutral. As you start to roll down the hill, apply the brakes. You'll need about twice the normal effort, and the pedal will move further to the floor before the brakes actually grab. You'll also be able to feel how much steering effort is required as well. Cars with very fast ratio power steering and wide tires (MINIs) are harder to steer than 50s-era trucks with manual steering!

 

Greatbear - good job of explaining this. Very few people realize that there is no vacuum produced at full throttle and how important it is NOT to pump the brake pedal and deplete the vacuum reservior in a run away situation.

 

Mine sticks to the floor too much.

 

 

So the Venza tested by CR (see post #31) must not have an "assist vacuum pump". That's why after pumping the brake, the power brake became ineffective.

I've always thought that all modern cars built in the last 10-15 years have an electric vacuum assist pump. It's there to secure sufficient vacuum in the brake booster when vacuum from the intake manifold is not high enough. I've not looked closely at the Mini system but my '01 New Beetle has one. It comes on only a few times a year. The sound is unmistakable... similar to the whine/buzz of the Mini PS pump.

 

FYI- The police officer that died was in a loaner Lexus sedan, that had the heavy rubber floormat over the carpet floor mat. The rubber floor mat was NOT for the sedan model, it was an RX300 (SUV) floor mat. The dealer he got the loaner from, had a similar incident reported by a previous customer, in that same vehicle, but had not done anything about it. He also was not familiar with the fact that he had to push and hold the "start button" (no ignition key) in order to shut the engine off.

 

Every time the light turns green and I am in front, my gas pedal goes all the way down. Seems to have a mind of it's own.

 

Yup, I've had intermittent issues on and off since I bought the car. My mini is currently at the dealer (again) and they are looking. The Regional Rep is supposed to come and look at it; I've sent numerous pictures to my Mini dealer. I've described it as "Toyota like" as of last week; I told the dealer that I can't believe I'm the only Mini with this issue. Only once did the "check engine" light come on; now, it doesn't register on the computer, but it sure is scary. Hasn't happened while I'm driving, but when I stop the car, the rpms can rev toward 4,000 at 0 mph.

 

Is there anyone other than me that would like to know why this has become such an issue that the news spends hours each day for the past 5-6 weeks covering it and now, Congress is holding hearings? I may have missed it but I don't seem to remember such coverage when Corvairs, Jeeps and Explorers were rolling over, Pinto's and Chevy Pickup gas tanks were exploding and all of the other U.S. auto makers were having problems that resulted in the deaths of motorists. A great book to read about the history of the U.S. auto industry is of course "Unsafe at Any Speed". Is this just a media tactic to take the heat off of the "home team" and give people a reason to buy American?

Sorry for hijacking the thread. The only time I've had a problem with the throttle in my MINI sticking is when my size 12.5 mashes the loud pedal to the floor and holds it there.

 

Well said Cadenza and actually I believe the call was found out to be the brother inlaw who was in the back seat. This accident was a total failure, from what they believe anyways. Meaning everything failed and nothing would stop the car. The video of the phone call is on YouTube and when you know the outcome, it's pretty hard to listen to. Here's an interesting video about a couple and their lexus troubles, 4 years before the CHP's officer and his family died. http://www.youtube.com/watch?v=gZWPI...eature=related

Anyone who believes that the officer could have done something else can listen to the 911 call themselves, they had NO brakes (again, this is very hard to listen to)
http://www.youtube.com/watch?v=03m7fmnhO0I

 

Good point cmcveay. While I do think that Toyota knew about this and put lives in danger for the sake of the almighty dollar, they are not the first. Although, there was actually quite a stink over the Pinto. When the **** hit the fan , Ford said they knew nothing of the problem with the Pinto before a certain date....that turned out to be a lie. The actual documents from the engineers, saying there was a problem, were found and they showed that Ford knew much sooner and it cost them a lot of money in law suits (the full report is on the internet). Yet after a year or so, the concerns went away and Ford sales climbed again. I think the big difference is the internet. When this happened to Ford, they really only had TV and newspapers to deal with, so once they got bored with the story and moved on to the next scoop, the problems faded from everyones mind. In this day and age, Toyota's problems are instantly in everyones face, it's all over TV, blogs, YouTube, Facebook, internet news sites, etc..etc....etc.....and they will remain there for everyone to read or see for years to come......welcome to the WWW.

 

Is your mini automatic? I've never experienced this on my R53-6spd but on several occasions I did on my wife's R53 auto. Here's one scenario. I just finished making a right turn on a slight uphill. When I stepped on it, it went redline and I had to back off the pedal a bit. I attribute this to the trans down shifting and me mushing the pedal.