David Jenkins
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| posted on 29/10/13 at 09:42 PM |
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Sometimes, I prefer a simple link from the accelerator pedal...
Many of you will have seen reports of Toyota cars running away out of control - I saw a link to a site describing Toyota's bad software
practices that may well have caused unwanted acceleration:
Toyota software report
It's a bit technical in its description, but it's not hard to get the gist of what they're saying - Toyota bodged the
'throttle-by-wire' software development and didn't understand how to test it (or chose not to do it properly). One problem was
found where a driver experiencing unwanted acceleration had to take his/her foot OFF the brake pedal to regain control - not easy to do, even if you
know it's required (which, of course, they didn't).
There's a lot to be said for a bit of steel cable between the accelerator pedal and the engine's fuel system...
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rdodger
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| posted on 29/10/13 at 10:16 PM |
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Exactly!
At least if the that single bit of wire fails the throttle closes.
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Scuzzle
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| posted on 29/10/13 at 10:45 PM |
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Toyotas were never just as good when they started making them outside Japan, If the sticker on the windscreen said 'Made in Japan' you
were fine. If it's made in the UK you took the chance that you could get a Monday morning car and if it's made in France then good luck
to you.
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coyoteboy
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| posted on 29/10/13 at 11:32 PM |
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My default reaction when the throttle sticks (has happened on my older cars) is to key off. Did the toyota system remove the ability to do this?
My brakes ALWAYS overpower my engine. I'm still confused as to how this ever became a problem.
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NigeEss
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| posted on 29/10/13 at 11:45 PM |
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quote:
Originally posted by coyoteboy
My brakes ALWAYS overpower my engine. I'm still confused as to how this ever became a problem.
I had a Mondeo TDCi runaway when the turbo seals went. Standing on the brakes only resulted in the clutch
slipping although the car did stop.
[Edited on 29/10/13 by NigeEss]
Time is an illusion. Lunchtime doubly so.................Douglas Adams.
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SteveWalker
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| posted on 29/10/13 at 11:55 PM |
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quote:
Originally posted by rdodger
Exactly!
At least if the that single bit of wire fails the throttle closes.
Not if some strands fail, splay out and prevent the throttle being pulled back by the return spring! BTDTGTTS. Luckily I realised the problem fast
enough to pull the accelerator up with my toe before I ran out of space. If it had snapped completely, it'd have been stuck open with no way to
release it.
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iank
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| posted on 30/10/13 at 06:01 AM |
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If I used recursion or ignoring/switch off casting warnings (two of the items listed) I'd sack myself on the spot.
Sounds like the job was given to a fresh graduate with only windows/mac/unix experience and minimal oversight. Code obviously wasn't properly
unit tested or even have a static code analysis (with MISRA checking turned on).
Shocking.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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hughpinder
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| posted on 30/10/13 at 07:19 AM |
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Personally I don't see the problem in a manual car - you dip the clutch (or do clutchless downshifts) when you brake don't you?
I did a skidpan course a few years ago. The first time I braked on 'ice' I hadn't pressed the clutch in fast enough and the engine
stalled. The instructor then said "OK, now imagine you've just done this on a dual carriageway, and there's a 38 ton truck doing 60
approaching you...."
By the way, don't do what coyoteboy suggests - you will almost certainly turn the key completely off, which engages the steering lock. I know a
Mercedes mechanic who did this test driving a customers almmost new S500 looking for a sticky thottle problem, when the throttle stuck open, he
turned the ignition off,which engaged the steering lock, he went straight through the hedge and wrote the car off. He'll tell you he feels
luckyto be alive since he had quite a bit of pace on at the time. It was an auto though so his other options were a bit limited.
Be careful out there!
Hugh
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TheGiantTribble
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| posted on 30/10/13 at 08:04 AM |
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Scary stuff, and yes I would go for the key to the off position route, and engage the stearing lock, and knowing my luck be right next to a cliff at
the time!
And what I personally find even more scary is modern planes with their fly by wire stuff
As BA used to say 'I ain't getting on no plane' seem a very sensible attitude to me.
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scudderfish
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| posted on 30/10/13 at 08:37 AM |
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quote:
Originally posted by TheGiantTribble
And what I personally find even more scary is modern planes with their fly by wire stuff
Because planes never crashed before they put those damned computers in......
I'd much rather fly on an A380 than a DH Comet, DC10 or L1011.
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Slimy38
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| posted on 30/10/13 at 09:08 AM |
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quote:
Originally posted by iank
If I used recursion or ignoring/switch off casting warnings (two of the items listed) I'd sack myself on the spot.
I've not had a chance to read the report, but those items would be bad on an average website, let alone safety critical systems.
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mcerd1
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| posted on 30/10/13 at 09:20 AM |
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quote:
Originally posted by TheGiantTribble
....I would go for the key to the off position route, and engage the stearing lock...
as I remember it the cars in question had 'safety features' that stopped you removing the key or pulling it out of gear on the move 
my tin-top has a steel cable and stick throttle issue, but that might actually be caused by a vac leak (can here some thing, but can't find it
 )
but I know that the steering lock only comes on when you pull the key out - you can turn it of and the steering stays unlocked 
I'm dreading the day when I have to get a 'drive by wire' car - I hate not being in direct control...
-
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PSpirine
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| posted on 30/10/13 at 10:44 AM |
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I've driven a fair few drive-by-wire cars, and more than a few conventional cable throttle cars.
The only ones on which I've had runaway or sticky throttle have been on the conventional throttles ironically! One was a diesel pump runaway,
which really couldn't care less whether you had a mechanical cable or servo attached to it, throttle did nothing. The other was in a mini which
had its lovely SU carb throttle spindle get stuck in the OPEN position. Had to engine off to kill ignition.
I have absolutely no problem driving a car where the throttle is controlled by a computer. I've yet to come across a car where the brakes
can't overpower the engine, and you can ALWAYS ignition off, even in cars with keyless button start (yes, I've checked this!).
To put it into perpective..
Toyota built 7,000,000 cars since the start of THIS YEAR. Even if 100 of them had unintended acceleration (and they didn't), I'd take
those odds.
(P.S. I don't work for Toyota, just trying to balance out the argument!  )
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MikeRJ
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| posted on 30/10/13 at 11:04 AM |
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quote:
Originally posted by iank
If I used recursion or ignoring/switch off casting warnings (two of the items listed) I'd sack myself on the spot.
Sounds like the job was given to a fresh graduate with only windows/mac/unix experience and minimal oversight. Code obviously wasn't properly
unit tested or even have a static code analysis (with MISRA checking turned on).
Shocking.
I quite agree, it's almost unbelievable this was allowed to happen. I used to work for a company making railway signalling equipment, and the
coding standards and number and strength of reviews for the safety critical stuff was so rigorous that 1) This would have been picked up very quickly,
2) You'd probably have been out on your ear for even attempting to do this.
Even in my current job I'd be kicking backsides if I saw this kind of sloppiness.
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rallyingden
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| posted on 30/10/13 at 12:34 PM |
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Fly by wire.......... PITA
It stops me left foot braking my Vectra  as soon as I put my foot on the brake the throttle backs off 
Oh well at least the twin 40's on the kit stay WIDE open with my foot on the brake 
RD
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richardm6994
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| posted on 30/10/13 at 12:41 PM |
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forget throttle by wire....I've recently read about "steering by wire" making it's way onto the market!!!
Now that one is scary if it was to go wrong!!
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coyoteboy
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| posted on 30/10/13 at 12:45 PM |
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quote:
By the way, don't do what coyoteboy suggests - you will almost certainly turn the key completely off, which engages the steering lock.
Sorry, but you'd have to be a bit simple to do that, so I'd be questioning your capability of driving safely anyway!
Plus I'd question your Merc mechanic's reason for crashing - a normal mechanical steering lock doesn't engage until the key is
removed from the lock, and I believe even the electronically controlled ones replicate that function and flag an alarm if the function if faulty -
that's a safety feature built into all ign locks to prevent inadvertent locking while in motion.
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coyoteboy
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| posted on 30/10/13 at 12:53 PM |
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Yeah I have to say that removal of steering control from the driver does scare the living daylights out of me - really something I'd not be
comfortable with. Like brakes - really wouldn't be happy with that being removed. I'm sure it'll all be double redundant, but
I'm an engineer and I know how badly these things could be implemented in a cost-conscious, fast paced market.
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David Jenkins
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| posted on 30/10/13 at 01:38 PM |
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I've had numerous automatic cars, and more than a few manual ones, but I've never had any that didn't allow you to go into neutral
or turn off the ignition - is this a new 'safety feature'? If so, I've not encountered it yet...
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Texan
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| posted on 30/10/13 at 02:12 PM |
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Yes, the Toyotas in question didn't have a key plus had a feature that required you to hold the start button a prescribed number of seconds,
make a certain funny face and put your finger up your butt in order to turn it off but even then it didn't turn off.
The transmission also wouldn't allow you to shift to neutral plus the brakes could not hold the car down on speed.
If you pumped the brakes you quickly lost power assist and on at least one of the cars the brakes were found to be toast afterwards. They simply
weren't up to the task of a long term run away engine. IIRC one of the crashes involved a Toyota mechanic and he didn't fare any better
than people off the street.
Drive by wire does allow some computer controlled features that a hard wired connection doesn't allow, but I'm old fashioned too, I
believe there must be some sort of physical connection even if it's nothing more than a mechanical, emergency OFF switch.
I drive therefore I am.
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coyoteboy
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| posted on 30/10/13 at 03:21 PM |
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quote:
Yes, the Toyotas in question didn't have a key plus had a feature that required you to hold the start button a prescribed number of seconds,
make a certain funny face and put your finger up your butt in order to turn it off but even then it didn't turn off.
If that's the case it's just blatant unsafe design.
quote:
The transmission also wouldn't allow you to shift to neutral plus the brakes could not hold the car down on speed.
Again, I just can't see it - not allowing you to shift, maybe, but brakes that can't hold the car - I call nonsense. I've got 300hp
4wd (50% more power than stock) and standard single pot calipers on 260mm discs on a 1.4 ton car and my brakes MASSIVELY overpower the engine
ESPECIALLY at speed. Modern brakes are even more over-servo'd than old ones. They'd have to be faulty or totally shoddy/undersized.
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rodgling
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| posted on 30/10/13 at 04:04 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by iank
If I used recursion or ignoring/switch off casting warnings (two of the items listed) I'd sack myself on the spot.
Sounds like the job was given to a fresh graduate with only windows/mac/unix experience and minimal oversight. Code obviously wasn't properly
unit tested or even have a static code analysis (with MISRA checking turned on).
Shocking.
I quite agree, it's almost unbelievable this was allowed to happen. I used to work for a company making railway signalling equipment, and the
coding standards and number and strength of reviews for the safety critical stuff was so rigorous that 1) This would have been picked up very quickly,
2) You'd probably have been out on your ear for even attempting to do this.
Even in my current job I'd be kicking backsides if I saw this kind of sloppiness.
I'm not convinced by the analysis though. The report was produced by the primary witness for the plaintiffs, i.e. his job was to make it
look as bad as possible so they could sue Toyota. So it is likely very very biased indeed.
For example, 11,000 global variables sounds incredibly unlikely and probably inflated as much as possible. I can only believe he reached that number
by treating arrays as hundreds/thousands of individual items (which is BS), and probably includes logged data which doesn't affect future
behaviour. I certainly don't believe there was an "absence of any bug-tracking system at Toyota" as this is just not credible.
All that said it does sound as if there were some serious problems... bit worrying.
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Bare
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| posted on 30/10/13 at 04:14 PM |
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Really? I watched the 'murican geriatric Penis head on video where he could not slow down let alone Stop his silly Prius, despite pressing on
the brakes. He drove like this for over an hour .. attempting to stop.
Post mortem showed that the Numpty had no idea of how to use the brakes.. as in : pedal pressure was proportional.
But hey! he had a drivers license .
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MikeRJ
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| posted on 30/10/13 at 07:25 PM |
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quote:
Originally posted by coyoteboy
[Again, I just can't see it - not allowing you to shift, maybe, but brakes that can't hold the car - I call nonsense. I've got 300hp
4wd (50% more power than stock) and standard single pot calipers on 260mm discs on a 1.4 ton car and my brakes MASSIVELY overpower the engine
ESPECIALLY at speed. Modern brakes are even more over-servo'd than old ones. They'd have to be faulty or totally shoddy/undersized.
If your 300bhp engine is running full chat then your brakes will be toast in very short order. It's quite surprising how difficult it is to
stop a car when the engine is pushing it constantly.
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Scuzzle
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| posted on 30/10/13 at 09:36 PM |
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Turning off the ignition is going to work fine for someone who knows cars but some people are going to get caught out even if they have the savvy to
turn off the car at the key
When you turn off the ignition the servo brakes are going to stop working and so is the power steering and there will be people who won't know
to allow for this.
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