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Toyota Pedal Issue Highlights Move To Electronics
cyclocommuter writes with an excerpt from a brief WSJ story on increasing electronic control of car components: "The gas pedal system used Toyota Motor Co.'s recall crisis was born from a movement in the auto industry to rely more on electronics to carry out a vehicle's most critical functions. The intricacy of such systems, which replace hoses and hydraulic fluid with computer chips and electrical sensors, has been a focus as Toyota struggled to find the cause for sudden acceleration of vehicles that led the company to halt sales of eight models this week."
Summary is stupid because there's no hoses and hydraulics in any car throttle system I've seen; if it's not electronic, it's a very simple and reliable steel cable.
Story is stupid because as it admits, the electronics had nothing to do with the problem; the failure was mechanical. The exact same thing could have happened to a cable-operated system.
By all accounts I can find, the issue with the Toyota's sticky gas pedal is a MECHANICAL one - not some electrical bug.
-Bill
According to AutoBlog, the problem with these Toyotas is a mechanical part in the drive by wire pedal assembly (and so it's not really an issue with the car being drive by wire). The pivot point that the pedal rotates on has a bushing that is apparently wearing out and causing the pedal stick. I'm a little skeptical as it seems much more plausible that it would be an electrical (or software) gremlin, but that's apparently what they're blaming it on.
There is still no excuse for Toyota not coding the ECU to cut throttle when it senses that the driver has BOTH the throttle and the brakes on simultaneously. All drive by wire VW/Audis are setup this way.
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The latest defect in Toyota cars is quickly developing into the scandal of the 21st century. The problem started when customers of Toyota vehicles began experiencing sudden unexplained acceleration; these incidents began appearing in 2002. Over time, Toyota management claimed that the problem is the floor mat. So, the management issued a recall to replace all the floor mats.
Then, after further studying the problem, the management claimed that the throttle's pedal sometimes becomes stuck due to weather conditions. This new claim lead to the massive global recall of many vehicles sold over the past 3 years.
However, none of these explanations for the sudden acceleration has been satisfactory. Independent investigations leading to an explosion of lawsuits have determined that the problem is the electronic throttle control (ETC) — the so-called drive-by-wire mechanism that links the pedal via some cables to the fuel controller. According to a report by "Businessweek" and another report by the "Wall Street Journal", Toyota is now the defendant in 3 separate class-action lawsuits. The plaintiffs claim that the ETC is defective.
According to a report by the "New York Times" (NYT), "a few years ago, the company sent out a technical bulletin saying some cars accelerate on their own between 38 and 42 mph, and it reprogrammed the electronics with new software codes".
The NYT notes, "John Heywood, director of the Sloan Automotive Lab at MIT, said because Toyota is the only automaker having this problem, it could be something specific to its design, such as the location and integration of the electronics relay sensor."
Further, the Toyota ETC lacks an important safety mechanism: if the customer presses both the throttle pedal and the brake pedal, then the ETC should give priority to the brake. The Toyota ETC gives priority to the throttle. How can Toyota engineers commit such a gross design mistake? Common sense tells us that the brake should receive priority.
I've been around the long-haul trucking business for decades, and I hate to break it to you, but for well over 10 years now, big rigs have had electronic throttle position sensors, with a little bitty, not even particularly well-protected wire running from the pedal to the engine ECM. This is ever since Detroit Diesel came out with their electronically controlled engine in the '90s which was an amazing breakthrough in mileage and reliability. So basically every truck that we've bought or ran for over ten years has had an electronic throttle pedal, and there have been zero problems, except occasionally the TPS itself needs replaced (like every million miles or so). In this case it looks like Toyota fucked up, but that doesn't mean using electronic controls is a bad way to go, because clearly lots of things seem to be able to implement them properly, including airplanes.
1992 - 1995 Isuzu Trooper recall for accelerator cable stuck causing uncontrolled acceleration
2003 Ford Escape stuck throttle cables result in uncontrolled acceleration
2002 Ford Explorers investigated for stuck throttle cables in cold weather regions
1999 - 2004 Suzuki Grand Vitara, recalled due to fraying accelerator cables that result in uncontrolled acceleration and potential crash.
I guess we need to go back to the tried and true horse and buggy as these cable controls do not have a good history of reliability. But we may need to investigate the buggy brakes to ensure the can overpower the horses.
I'm not sure what happened in your bucking Bronco but O2 sensors do not control throttle position, worst case scenario would be an oscillating idle RPM as the computer adjusted fuel mixture from lean to rich. As long as your not touching the accelerator its not going to accelerate uncontrollably and will simply run like shit.
They did a test on 3 separate cars, Toyota Camry, Infiniti G37, and Roush Stage 3 Mustang to see the effective stopping power brakes at 70 mph and 100 mph, and each with no throttle and each with full throttle.
Only the Roush Mustang 3 had any real issue of slowing down with full throttle - but only at 100mph. It did stop eventually, but took 903 feet (vs about 320 feet with no throttle).
In the 100mph full throttle tests, the Camry stopped within 88 feet (vs no throttle), the Infinti within 6 feet (The Infiniti has a system that as soon as brakes get tapped the throttle closes, hence such close numbers)
So yes, for 99% of the cars on road, your brakes will overcome your engine easily.