Accelerating hard while braking

[colintrax]

You guys, you're throttle can only be opened with a cable attached to the gas pedal, the cable attached to the cruise control (which should be off if not being used) and the IAC (which can't speed the engine up to much)

Trust me, it's your foot hitting the gas pedal. I think the pedals are just a little to close together in the explorer, it's easy for your foot to hang off the edge and also hit the gas pedal.

The recall on the cruise control is just a fuse or something like that. Cruise control won't speed you up on purpose, it simply holds the speed unless you tell it otherwise. Even if you hit the buttons to speed up, it only changes 1mph at a time.

This thread needs to die, I don't even see how a floor mat could cause this considering how high up the gas pedal is, and the way it's designed.

 

[lugnuts55]

I hate to tell you folks but my98nnj and colintrax are right. There is nothing mechanically wrong with your Explorers as far as this issue is concerned. I have to wear special shoes to accommodate the weird things my feet are doing as I age. I spent almost 40 years as a mechanic working on concrete every day. The shoes are bigger than regular shoes and will easily brake and accelerate at the same time.

I have to be careful when I brake. I have braked and accelerated together several times and it does get scary, especially if you are making a left turn and waiting for traffic. And it's even more scary when the wife is along and she instinctively goes for the invisible brake pedal on the passenger side.

Just try to step on the brake pedal more in the middle instead of the right end of it. Practice it in an unused corner of a grocery store or Walmart parking lot. Don't read too much into this because you will spend a lot of time chasing ghosts.

 

[ponkotsu]

I hate to tell you folks but my98nnj and colintrax are right. There is nothing mechanically wrong with your Explorers as far as this issue is concerned. I have to wear special shoes to accommodate the weird things my feet are doing as I age. I spent almost 40 years as a mechanic working on concrete every day. The shoes are bigger than regular shoes and will easily brake and accelerate at the same time.

I have to be careful when I brake. I have braked and accelerated together several times and it does get scary, especially if you are making a left turn and waiting for traffic. And it's even more scary when the wife is along and she instinctively goes for the invisible brake pedal on the passenger side.

Just try to step on the brake pedal more in the middle instead of the right end of it. Practice it in an unused corner of a grocery store or Walmart parking lot. Don't read too much into this because you will spend a lot of time chasing ghosts.

I'd love to see the scientific/engineering based explanation of how the brake can accelerate this vehicle. And if it's possible, then it should be easily reproducible, which nobody has ever done on any vehicle without major modifications. Until someone explains that, I'd say it's just human error.

The only one I know that really happened was the 70's ford trucks that would slip into reverse. I actually witnessed that once and was almost run over by the truck. It damaged about 10 other vehicles in a crowded lot before stopping. But that was an easily explainable mechanical design flaw.

 

[swshawaii]

IIRC, a binding or sticking accelerator pedal was caused by broken motor mounts. Still possible? :roll:

 

[lugnuts55]

I'd love to see the scientific/engineering based explanation of how the brake can accelerate this vehicle. And if it's possible, then it should be easily reproducible, which nobody has ever done on any vehicle without major modifications. Until someone explains that, I'd say it's just human error.

The only one I know that really happened was the 70's ford trucks that would slip into reverse. I actually witnessed that once and was almost run over by the truck. It damaged about 10 other vehicles in a crowded lot before stopping. But that was an easily explainable mechanical design flaw.

Ok, maybe I should have made it clearer than I did. I said in the 2nd paragraph that "I have braked and accelerated together several times". The brake pedal and the accelerator are close enough together that I sometimes get my shoe far enough to the right end of the brake pedal and this is what happens.
Nobody suggested or implied that the vehicle accelerated just by stepping on the brake pedal. There were several other people posting that it had to be a vehicle problem. I just wanted them to know of the great possibility that the problem is driver induced. That's all.

 

[colintrax]

IIRC, a binding or sticking accelerator pedal was caused by broken motor mounts. Still possible? :roll:

How in the hell does a motor mount make the pedal stick????

 

[swshawaii]

How in the hell does a motor mount make the pedal stick????

That's why I asked if it was still possible. Apparently it still happens on non drive by wire systems. Used to be a fairly common occurrence with vehicles built before the 80's. Happened to me twice. Did a quick search and found these:

http://www.ehow.com/how-does_4896489_what-happens-engine-mounts-bad.html

http://books.google.com/books?id=VX...a=X&ei=YM7oUO6JL-iWjALbwYEo&ved=0CGcQ6AEwBzgK

 

[Birdy]

What if the brake booster was leaking a lot when the pedal is pushed, huge vacuum leak could rev the engine a bit. ???

 

[1996BLKBauer]

On the low pedal due to worn pads thing... I'm not buying your theories. Disc calipers are totally self adjusting. Drums brakes could cause a lower pedal if the self adjusting mech isn't working, but that can't be with calipers. Yes, the fluid level will go down in the master cylinder reservoir as the pads wear, but thats because there's more fluid being stored in the caliper behind the piston(s) to make up for the pad wear. That's not going to make the pedal go any lower. Now, if you theory is that you're having to press harder on the pedal to stop (due to severely worn pads/lose of friction) and the pedal goes down further due to the increased pressure you're applying, that i can understand.

It made sense in my head... Yours makes more sense though. my pads were real bad, the person, or dealership I got it from bent back the wear tabs so they where toast when I finally got to them

 

[FIND]

What if the brake booster was leaking a lot when the pedal is pushed, huge vacuum leak could rev the engine a bit. ???

One would notice the difficult to press brakes first though... Not to mention, you would have that leak at all times.

 

[ponkotsu]

One would notice the difficult to press brakes first though... Not to mention, you would have that leak at all times.

And it wouldn't cause more than a few hundred rpm change in engine speed. It won't cause the throttle plate to open.

 

[ponkotsu]

It made sense in my head... Yours makes more sense though. my pads were real bad, the person, or dealership I got it from bent back the wear tabs so they where toast when I finally got to them

I design hydraulic disc brakes for a living. (Not specifically automobile, but the principles are the same.) I'd like to explain why the pedal stroke increases but I can't because much of what I know took me many years to learn and is confidential. But it is true that the pedal stroke will increase. There are a number of factors that cause the phenomena. There should not be a dramatic increase though. If you have more than an inch or so of pedal increase, that would indicate some other problem other than just worn pads.

 

[colintrax]

That's why I asked if it was still possible. Apparently it still happens on non drive by wire systems. Used to be a fairly common occurrence with vehicles built before the 80's. Happened to me twice. Did a quick search and found these:

http://www.ehow.com/how-does_4896489_what-happens-engine-mounts-bad.html

http://books.google.com/books?id=VX...a=X&ei=YM7oUO6JL-iWjALbwYEo&ved=0CGcQ6AEwBzgK

I guess that would possible on some vehicles. However looking at the explorer's throttle linkage, it wouldn't happen.