To explain: Old days, carburetors had "flapper valves" in them called throttle plates. Those controlled how much air entered your engine, and, therefore, how much power was being called for. Carbs (not carbohydrates!) went obsolete with the introduction of Electronic Fuel Injection, which is now universal. Early EFI, as intended, easily met the emission standards. My Mustang always registered zero carbon monoxide! EFI uses a throttle plate, just like carbs did. It is opened and closed by the driver's foot, just as with carbs. Through the 1990s this was standard practice. The driver's will was exercised directly upon the engine mechanically, by being connected to that person's foot. The computer, Powertrain Control Module (PCM) took over from there, interpreting electronically how much power the driver was demanding. Around 2000, the first I knew of, (and many of you will recall), one of the first to take away the "driver's will" was Toyota. It took a number of years for a sufficient number of accidents of various degrees of severity to bring the results of this "usurpation" to the public's, and administrators' attention. Their vehicles were occasionally going "wide-open" throttle BY THEMSELVES! In the end, Toyota, after claiming the cause was "sticky throttles", agreed to pay over $ 1 Billion in restitution. It was staggering. If interested, here: http://abcnews.go.com/Blotter/toyota-pay-12b-hiding-deadly-unintended-acceleration/story?id=22972214 Here's what actually was happening: The "gas pedal", or throttle, had become no longer a mechanical link from the driver's foot to the mechanically-operated throttle plate, but was now an electronic link to the PCM, simply a variable resistor which fed a varying voltage to the PCM. PCM takes that voltage and, interpreting it's strength, sends it's own voltage to a tiny electric motor mounted on the throttle plate mechanism. This became euphemistically called "Drive By Wire". DBW is nowadays standard practice, like it or not. Toyota slipped up by not ensuring their design was "fail-safe". Why did the industry go to this extra cost and decidedly complex design change? Mainly, it seems, to give authority to the PCM to over-rule the demands of the driver, if deemed necessary. Basically, your computer can now disable your vehicle! Not kidding you! It happened to me! Detection of a serious operating "fault" can result in a number of reactions by the PCM. It can call for "Forced Reduced Power", commonly called "Limp-Home Mode", which greatly reduces power available, but allows the vehicle to remove itself from the roadway. One of the many "faults" which can cause Limp Home is some problem with the engine, or transmission. The next higher level of control is called "Forced Engine Idle". Means just what it says: you push the pedal, nothing further happens, engine idles only, car can creep forward (or backward). I experienced this one, too! Finally, the nightmare: "Forced Engine Shutdown", engine will not start or run at all! Fortunately for me, the first "Limp Home" for me happened in the middle of nowhere, and my "Scan Tool" erased the code causing the limp, and I was able to drive home. It came back, though, every 5 or 10 miles, driving me to distraction as I searched for the cause. No, the trouble did not lie with the Drive By Wire, though that's the first place Mechanics go looking when encountering this fault. I replaced the Electronic Throttle Body; No fix. Calling this long story shorter, I finally learned the designers in their empirical wisdom have empowered the Antilock Brake System (ABS), as a safety measure, giving it also the "power" to shut us down, separate from the PCM! Finally, (whew), in 2008 the Fed mandated all new cars sold be given "Permanent Digital Code" abilities, which means certain codes persist and cannot be "erased", as I did with mine. Frank
I have no idea what you are talking about which is probably a good thing because I don't have any of these problems that follow you. All I know is I can turn my ABS off or on. My husband was the car expert, his field was catalytic converters and he even patented a few for a company. Before that he worked in R&D at Midas.
From what I understand with the new technology of cars, there is that black box called computer that controls everything. There is an issue here of a particularly type of a brand of car that goes SUA (sudden unintended acceleration) which makes the car move (depending on the gear) and ignores any driver interventions. More than a hundred cases are pending in court with their class suit against the manufacturer of that Japanese car but our own department of trade and industry seems not to be doing anything. As per the explanation of one knows new cars, that SUA may be caused by a bug in the programming of the car's computer. When you step on the gas pedal, it sends a signal to the computer which in turn commands the fuel injector to give it gas. Likewise with the breaks. So it seems that we are now at the mercy of the little black box.
@Corie Henson Close enough to win, Corie! I wonder if those cases involved Toyota Co.? Not familiar with others' design, but my Ford has a fail-safe design which compares two simultaneous outputs from the gas pedal. They must always move "in-step", never unequal, if they do go unequal, the vehicle is disabled. Frank
I had a ford Torino in the 70's...our second one. It was possessed because it would take off without me stepping on the gas and wouldn't stop when I braked. Got rid of that fast.
It's a MItsubishi Montero starting with model 2002 (I don't know until what year). There were cases documented with CCTV video which looked like the SUV went amok and it's a good thing that those incidents have no fatalities although the damage to the vehicle is costly. Worse, there are incidents that the wayward SUV had damaged other vehicles since the driver had lost control of the gas pedal and the brakes didn't work.
@Corie Henson I especially like your mention of the vehicle going amok, Corie! Extremely frightening circumstance for the average driver, especially the relatively inexperienced. Just moving along, casually, and suddenly, your machine lurches forward under full power, your foot off the gas pedal! I had this happen, many years ago, when a car I was "building" had a binding-up of the throttle linkage. I had "floored it", but removing my foot, it remained under full power! It happened with my then new Ford Mustang, not Ford's fault, but my own! I had rigged a mechanical linkage to open the carburetor's rear barrels, and it had jammed, wide open! What did I do? Shut off the key as soon as I could, killing the engine. Frightening as hell, though. Of the million things which can go wrong, human frailty is bound to overlook a few.......Frank
There was this report by a woman of the same SUV brand that went out of control while they are traversing the ramp down from the car park building. Fortunately the speed was still manageable so they were able to reach ground level until it stopped when the SUV hit something (I think it is a post in the exit ramp). The woman claimed that her husband had tried to turn off the key but it wouldn't. And I have to believe her because she was crying and looking scared in the video of the interview. So when the SUV takes control from the driver, it seems that no one can do anything about it until it hits something to make it stop.
Excellent post @Frank Sanoica. This is all good to know and scary. We've only purchased used vehicles. Now that I am aware of this 'control' thing I am sure to limit my search for earlier model vehicles in the future. I'm sure there are 'old school' mechanics around which lack the appeal of the new technology around today's high end vehicles. When I look under the hood I like to see what's wrong rather than see a big metal box that hides the problem.
@Von Jones "When I look under the hood I like to see what's wrong rather than see a big metal box that hides the problem." Nowadays they've even done away with that! My box is plastic! That opens the door for yet another discussion concerning extreme remorse to owners, but passing it's threshold is best done elsewhere! Frank