Car "charging" while braked at stop?

Goldilocks · #1 11-20-2009, 03:13 PM

I've searched threads but haven't found any similar links. While in line waiting for my order at McDonalds, I had my foot on the brake, car was at full stop & it 'charged' ahead. This has happened a couple times.

Anyone else have/had this problem? What solution/resolution? My Cricket has less than 6,000 miles on her & not 3 yrs old yet.

ran-o-matic · #2 11-20-2009, 05:18 PM

Let me get this straight - You were fully stopped, with your foot on the brake pedal, and the car moved? Your sig says you have an '08 MCSa. Do you have the floor mats? are they secure? Are you sure the driver's mat is clear of all pedals?

Goldilocks · #3 11-20-2009, 08:38 PM

I have secure floor mats. There was no obstruction on or around the gas pedal or brakes. The driver's mat is clear, totally clear. It hasn't happened since, but I now put the car in P when I'm going to be stopped in MacDonald's line to p-revent recurrence. Anyone else have this happen to them?

Benibiker · #4 11-20-2009, 09:01 PM

I think it's called "surging" and no it's not a common problem on Minis but it could happen. I would have it checked out.

KevinC · #5 11-21-2009, 01:11 PM

Impossible.

Your brakes will win out over the throttle, 100% of the time. Try it. Stand on the brake, and then hit the gas. The car won't go anywhere, until you release some brake pressure.

pilotart · #6 11-21-2009, 01:50 PM

Don't know about a MINI 'S', but my previous ride was a TurboCharged Chrysler.

It had a Check-Valve at the Power Brake Vacuum accumulator to prevent Boost Pressure from entering the Vacuum Chamber.

If this Check-Valve failed, it would affect the Brakes (none while boost was above ambient and slower 'assist' to the brakes with no boost).

markjenn · #7 11-21-2009, 04:10 PM

Quote:

Originally Posted by KevinC

Impossible.

Your brakes will win out over the throttle, 100% of the time. Try it. Stand on the brake, and then hit the gas. The car won't go anywhere, until you release some brake pressure.

It's not impossible if the car isn't fully braked. You're right, the brakes can always overpower the engine and stop the car, but you may have to brake quite hard, and most people typically are going to be braking only hard enough to avoid creep while sitting in a McDonald's drive thru. If the engine surges for some reason, the the car could easily move.

- Mark

Benibiker · #8 11-21-2009, 06:30 PM

Quote:

Originally Posted by KevinC

Impossible.

Your brakes will win out over the throttle, 100% of the time. Try it. Stand on the brake, and then hit the gas. The car won't go anywhere, until you release some brake pressure.

If you're sitting at a traffic light or a drive-thru, you're only applying enough brake force to hold the car. If the car suddenly surges it won't hold unless you apply more brake pressure. What about those people that got killed in a runaway Lexus, they were supposedly applying full break pressure but the gas pedal was stuck full down. In that case the gas won over the brakes...

Nimcosi · #9 11-21-2009, 10:33 PM

I had put something snarky here about neutral and ignition. But I thought better of it so here is all that is left.

Oxybluecoop · #10 11-22-2009, 12:52 AM

Never had mine surge while I had the brake depressed. I always have mine in manual mode and when dropping it into second I can take my foot off the brake and it says put whether it's a flat road or incline.

markjenn · #11 11-22-2009, 01:14 AM

Quote:

Originally Posted by Benibiker

What about those people that got killed in a runaway Lexus, they were supposedly applying full break pressure but the gas pedal was stuck full down. In that case the gas won over the brakes...

Nope, as stated earlier, if you're applying full pressure to the brake pedal, there is no way the engine can develop enough torque to cause the car to move. The brakes can develop SEVERAL TIMES OVER more torque than the engine can develop.

The Lexus (and more famously) Audi drivers who report that the car ran away while applying full brake pressure were victims of pedal error - they thought they were applying full brake, but they weren't. Pedal error is quite common. Although I don't think it has anything to do with the OP's problem which sounds like some kind of engine surge while they had the brake LIGHTLY applied.

- Mark

**schatzy62** · #12 11-23-2009, 02:26 PM

Quote:

Originally Posted by markjenn

Nope, as stated earlier, if you're applying full pressure to the brake pedal, there is no way the engine can develop enough torque to cause the car to move. The brakes can develop SEVERAL TIMES OVER more torque than the engine can develop.

The Lexus (and more famously) Audi drivers who report that the car ran away while applying full brake pressure were victims of pedal error - they thought they were applying full brake, but they weren't. Pedal error is quite common. Although I don't think it has anything to do with the OP's problem which sounds like some kind of engine surge while they had the brake LIGHTLY applied.

- Mark

Full and utter BS.

1. If you are stopped at a light or any other point you are not applying FULL brake pressure. The car WILL surge if there is a engine torque/rpm increase before you have time to press harder on the pedal to apply more pressure.

2. Now if your are "standing" on the brakes you can and will be able to get the car to move by applying enough engine power. Now with that said you will burn up a clutch or other parts trying to do it but at some point the car WILL move.

3. For those people you are talking about with "pedal error" again full and utter BS. The people in question and the car manufacturer were both able to prove it was NOT a case of mistaken pedal push (pedal error) The car did continue to be able to be forced to move with a stuck throttle. And in fact there is more than one report of this on more than one model of car.

miniemee · #13 11-23-2009, 03:54 PM

This is one reason why i wont drive an auto transmission. I want control over the car not it over me. Manual and clutch all the time.

Benibiker · #14 11-25-2009, 12:18 PM

Toyota’s push-button ignition system makes turning off the vehicle in case of a jammed accelerator pedal more difficult as happened with the Lexus case. In the Lexus pressing the button while the car is motion will not shut the engine. I wonder how the Mini start/stop button works, will pressing it while the car is motion shut down the engine or not? Just something good to know just in case...

Nimcosi · #15 11-25-2009, 05:54 PM

In the R56, holding down the start/stop button will shutoff the engine, even when in motion. No different than a key.

BlimeyCabrio · #16 11-25-2009, 06:14 PM

I've done this a couple of times in my first gen. In each case, I *thought* my foot was firmly on the brake pedal - but actually was hanging off the right side just a wee bit - the pedals are close enough together on the auto that I caught the edge of the accelerator with the edge of my shoe... so was inadvertently pressing both at the same time...

ran-o-matic · #17 11-25-2009, 07:42 PM

Quote:

Originally Posted by BlimeyCabrio

I've done this a couple of times in my first gen. In each case, I *thought* my foot was firmly on the brake pedal - but actually was hanging off the right side just a wee bit - the pedals are close enough together on the auto that I caught the edge of the accelerator with the edge of my shoe... so was inadvertently pressing both at the same time...

I guess I need to try that on my Clubman. I thought the throttle-by-wire system would cut the throttle on a second gen any time the brake is pressed. Bad for left foot braking, but the safe thing to do.

That's why my first question (way up) was about floor mats. With the auto, if you have enough pressure on the brake pedal to stop the car, it really shouldn't be able to move again. I thought maybe a floor mat was preventing the brake from staying pressed.

Another option would be the brake switch not working correctly combined with a throttle control issue (like surging from above) and light pedal application.

Benibiker · #18 11-26-2009, 12:11 PM

Quote:

Originally Posted by Nimcosi

In the R56, holding down the start/stop button will shutoff the engine, even when in motion. No different than a key.

That's good to know

.

colejd · #19 11-27-2009, 06:35 AM

Goldilocks,

Does this surge also occur as you are just about to stop? My 08 MCCS jumps from 600 to near 800 RPMs, regularly, just before I come to a complete stop. While not dangerous (as I maintain a firm foot on the brake pedal) it is unique to any other car I have owned. I am getting my MCCS back this morning after a week at my Mini dealer. I needed the week to let them to reproduce the cold start rattle (they did and made the repair), perform the required maintenance, Fix a number of speaker issues (Thanks Hi-Fi!), and finally to map the engine surge characteristics (to hopefully help Mini corporate determine a computer fix). During the week I had a 09 MCS auto loaner and it did the same thing so I guess I am not the only one.