Saturday, February 20, 2010

Toyota, Sticking Gas Pedals and Parking Brakes

I have heard and been reading - as many of you have - with interest and concern over these so called sticking gas pedals and accounts of using the parking brake to stop in an article "Runaway Camry Crashes Raise 'Huge red Flag'" on msnbc (Google it). For one thing, sole electronics over mechanical control devices like throttles should be avoided at all costs. Electronics can fail, and do, for many reasons such as exposure to heat like under a hood near an engine, hot and cold weather, moisture, rubbing against under hood items, deterioration, loose and frayed connections of wires etc. Ever had electric windows, antennas, door locks and even electronic dashes go on the fritz? These things fail all the time but is mostly an annoyance and not life threatening. Putting throttles under electronic control is ludicrous and the engineers who thought this up should be bitch slapped and hard.

This sticky pedal excuse is so out there it boggles the mind. When you set your cruise control (Has Toyota looked at malfunctioning/short circuited cruise control devices?) your vehicle holds a set speed you have selected, it does not continue to accelerate out of control. Yes, it varies the speed when going down hill or up but it maintains the set value instead of careening out of control. Most vehicles have mechanical linkages to the throttle and a small solenoid moved the throttle cable back and forth to maintain control. With cruise activated you can still throttle up with the gas pedal but when you release pressure on the pedal the speed resumes where you have it set. Now lets say that same solenoid were to malfunction and stick what would happen? At first nothing perhaps while on a flat plain but then as your vehicle climbs a slight rise of the road the system will try to throttle up to maintain speed up the hill but upon sticking the throttle just keeps applying even on the flat plain again. Now this would be a sticky throttle problem and not what we are being led to believe by Toyota. If your driving down the road at twenty five MPH and you have not applied anymore pressure to the peddle then why would the car all of a sudden speed out of control? You have been motoring along and all of a sudden the car starts going faster and you have done nothing, this is not a sticky pedal this is an electronic failure to me. If you had a mechanical throttle chances are the throttle might stick at the twenty five mile an hour you were going but it would not accelerate wildly out of control and if the gas peddle did happen to stick usually a couple of good quick stomps on the peddle would free up the mechanical system. Are these Toyota owners perhaps stomping the peddle in hopes the gas peddle will become unstuck as this would work in a mechanical system but not an electronic one?

Or might it be something to do with the fuel injection system which is causing the injectors to keep adding more fuel? What was the outside temperature during all of these reported incidents? Injections systems work under pressure so could it be the pressure in the fuel tank gets to high and the vent system does not work so the rise in pressure forces fuel to the injectors causing out of control acceleration? I still think it could be with malfuntioning cruise control. But what do I know? I'm just a little guy so why would Toyota and their engineers ever want to listen to someone like me with only a small engine degree. It already took years and several lives before they even looked into it at all with mounting reports from sources like Insurance companies who did their part by questioning it.

Now on the subject of using the emergency brakes to stop the car. This does not seem to work very well like the one case mentioned in the MSNBC article about Mrs. Bookout,76, in September 2007 who's Camry accelerated out of control she applied the parking brake but the car's rear tires skidded 150 feet before crashing. Two other persons in their seventies also crashed their Camrys and officials blamed the age of the driver as the factoring cause of the crashes, but now I think these persons were wrongfully accused.
But why did the emergency brake not work and why does it not help in these newer cases? The reason is very simple actually, on vehicles with rear wheel drive the emergency brake has a better chance of being effective because it is applying braking force to the wheels that are powering the vehicle and this braking force will also add stress to the engine dragging the rpms down thus slowing the vehicle. All of these Toyota cars are front wheel drive but the emergency brakes are still used on the rear wheels where there is no power, the rear wheels are only pulled along by the front wheel drive therefore all the emergency brake is doing is locking the wheels up but no added strain is put on the engine as the engine powers the front wheels. If the emergency brakes were hooked to the front wheels then you would have a better chance of slowing and stopping the car but as it is all your doing is applying such little drag while the engine roars along with no braking force.

And think of this to about emergency brakes these days, most cars built now do not even have an emergency brake, what they have is a hill/parking brake. This is not the same as an emergency brake. A hill/parking brake is one of those pedals you push down to set with your foot then push again to release, there is no handle to pull to release the pedal. An emergency brake is one that has a handle or button you either pull or depress to release the brakes from its applied position. This system allows you to control the pressure you are putting to the emergency brake to slow down as a backup to your normal brake system. When taught and practiced you can slow a vehicle to a stop safely without locking up the rear wheels.
With only the hill/parking brake all you can do is stop the pedal down which locks the rear wheels only causing a skid which could also cause a crash.

To sum it up, I think Toyota has had this throttle problem for longer than we think and they have been dodging the problem for years and would have kept doing it as long as. for example: Driver error and driver age seemed to work for the explanation.
I'm sorry but if I owned a Toyota, I'd be parking that thing at the dealers and refuse to make any further payments on it until it was fixed right and not patched. I mean is your auto insurance going to honor any claims now on a car known to have this problem and you are still driving it?

3 comments:

Willy D said...

I concur. I don’t believe any of this is mechanical. Floor mats? Add a spacer to the gas pedal? Now the power steering is whacko. Electronic systems are great when they work. But one little hiccup and who knows what’s going to happen. For example; most electronic systems perform a self-check. You’ll notice that all the dash lights flash or the gauges sweep to the max and back again. But this does require that you turn the system on and wait the required 4-6 seconds for the self-check before starting the engine. How many people do this? Is the self-check aborted if you don’t?

As for the parking brake I again agree. Any secondary braking device, (as far as this issue is concerned), installed on a non-powered axel is stupid at best and really stupid at worst. All of my autos are rear wheel drive with a emergency brake that can either slow or stop the powered axel. Very useful for stopping wheel spin on mud or ice.

Doug said...

Throttle-by-wire is common place in cars now. Electrically assisted power steering is also replacing the old hydraulically boosted systems.

Anti-lock breaking is about a computer interrupting your brake function as it deems best.

TRW has been working on full steer-by-wire for a decade now and according to an engineer I knew at TRW several years ago the only hold back to implementation is public resistance. I'm thinking the Toyota debacle is going to set that back another decade and that's fine with me.

FLHX_Dave said...

The throttle on my glide is all electronic and this whole toyota deal has me rehearsing what I am going to do when my bike decides to go rogue on my ass.

I love the electronic throttle control on the bike. I guess only time will tell as to whether it was a good idea or not.