Accelerator stuck wide open while car is going fast: what should you do?

This question was posed in a video reconstruction of an incident in the US.
You were offered three choices:
- yank on the handbrake - put the car in neutral - turn off the ignition
The "correct" answer was to put the car in neutral. Turning off the engine would lock the steering. Pulling on the handbrake would lock the rear wheels.
I'm not sure I agree with their answer.
I had this very thing happen to me - when I was learning to drive. I was going up a steep hill so I was in a low gear with the engine going quickly. When I got to the top and changed from second to third, the engine raced but I put it down to bad clutch/accelerator coordination. When it happened again as I changed to fourth, I realised it wasn't - especially as the car shot forward like a scalded cat.
I realised what had happened very quickly and also knew what would happen if I pressed the clutch or put the car into neutral, which was my first instinct: the engine would race very quickly and if it went well over the redline speed, it could well throw a piston which would be very bad news if all that fast-moving metal came to rest in an instant.
So somehow I managed very calmly to turn the ignition just far enough to kill the engine by putting it into the accessory position without turning all the way off. Had I been travelling "at 120 mph with the engine redlining" (as it said int he video) it might have been a *little* more difficult to turn it just the right amount. ;-)
Am I right that the last thing you want to do is let the engine greatly exceed its redline speed and risk it seizing up (I'm assuming that the car is old enough not to have a rev-limiter)? Do any steering locks actually lock the steering while the key is still in, even in the off position? I thought it only locked when the key was removed - for this very reason, so you can safely turn off the engine in the event of an emergency.
Discuss...
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On 22/07/2018 22:11, NY wrote:

No all cars have an Acc posn on the Ign switch.
You could use the handbrake partially, ie not full on.
Over reving the engine is the lesser of the evils compared to a high speed collision.
If you just turned off the engine on a manual, in neutral, then turn ign on, you could steer without power steering and have basic brakes.
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On 22/07/2018 22:28, Brian Reay wrote:
<snip> > You could use the handbrake partially, ie not full on.
Probably the worst thing you could ever do.
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Why use the handbrake at all, if the footbrake is still working fine?

I was thinking in terms of a con rod breaking which would probably seize the crankshaft which would be bad news with the energy of the large mass of the flywheel having to be dissipated very rapidly as it came to rest, possibly locking the transmission (even with the slight clearance of a clutch pedal being pressed) and hence the wheels.
I don't know how fast an engine might turn if all the mechanical load is removed at full throttle, and how much extra load this would place on the con rods. Modern cars with fuel injection and and ECU would almost certainly have a rev limiter. But the car I was driving was much older than that, with a carburettor, so there would be no limit to the engine speed, other than normal engine friction and the maximum fuel flow that the carb could manage.

As it happens, the car no PAS and no servo brakes, so neither would have suffered.
I have since (in a much more recent car) driven with no PAS when my "fan belt" broke at 70 on the motorway. Getting the car off the motorway to a garage where I could wait safely for the RAC took a bit more effort to steer than normal, but was not impossible. Strangely the brakes did not seem to be affected, so maybe the brake servo is driven by something other than the "fan belt". Obviously on a car with an electric fan, the one thing that the belt does not drive is the radiator fan. Having seen the tortuous path that the belt ought to take (it had vanished and was probably in Lane 3 of the motorway) I wasn't going to attempt to jury-rig a replacement, even if I'd had anything to make a long enough loop. It's as easy as in the days of a longitudinal engine where the belt just goes round three pulleys (alternator, water pump and fan) and is at the front of the car, without loads of tensioning pulleys and very little space to work between the engine and the front wheel. Even the RAC man said it was virtually impossible on a modern car to replace the belt at the roadside, even if he carried the right spare for the car.
Would you believe after I had the belt replaced at my local garage, the replacement failed in the same way about 2000 miles later. The garage had failed to spot that the flanges of one of the pulleys were bent out of shape, which had shredded the replacement belt and may well have been the cause (rather than the side-effect) of the first belt failing. The garage denied all liability and wouldn't pay anything, so I stopped using them.
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On 22/07/2018 23:50, NY wrote:

Although you say below the car has no brake servo, I was thinking to compensate for the loss of the brake servo vacuum with the ign off.

If the car is in neutral it won't lock the wheels.

There can't be many of those around.
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I think very car I've drive with servo brakes, the footbrake has worked far better even with no servo than that handbrake as a means of slowing the car down, as opposed to holding it when it's already stationary.

I was thinking more of simply pressing the clutch - easier to do without taking hands off the wheel while trying to steer round objects ahead, rather than trying to find neutral in the heat of the moment.

No. This was 40 years ago on my mum's Renault 6.
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Turning off the ignition doesn't stop the brake vacuum servo working. That will continue to work while the engine turns. Which will be as long as the car is moving, if left in gear.
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On 22/07/2018 23:50, NY wrote:

Obviously it depends on the engine, but most overhead valve engines had a sufficiently heavy valve train that valve bounce would seriously interfere with beathing and limit revs. I am aware of a 1300 Ford Escort where after a prang had the throttle jammed. It wouldn't restart. The valves had touched the pistons and bent. No other damage and worked fine after the valves were replaced.
An old Mini engine above certain revs would make a characteristic clatter, above which there was literally no power and the engine would simply sit there at around 5-6,000rpm.
As soon as ignition modules came onto the market they inherently would incorporate a rev-limiter. There were some aftermarket rev limiters you could add to the old contact style ignition system.
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Hmm. They were lucky the valves didn't punch a hole through the pistons.
I remember my garage warning me with my first diesel car that it was an "interference engine" - ie the valves occupied the same space as the top of the piston, though at different points in the cycle. Consequently it was even more important than normal for the timing belt to be changed at the manufacturer's stated intervals, in case it snapped and the pistons and valves collided. The garage also advised with my present car that they should change the water pump (driven off the timing belt) while they were replacing the belt, even if it seemed fine, so as to not incur a second engine removal cost if the pump should subsequently fail. The extra cost of a pump that may or may not need replacement was peanuts compared with the labour of making the timing belt accessible - so kill two birds with one stone.
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On Sun, 22 Jul 2018 22:28:53 +0100, Brian Reay wrote:

Indeed. And keyless ignition is usually 'press the button and it all goes off'

Electric handbrake? (IYSWIM)
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Yes, keyless ignition and electric handbrake are both a bit all-or-nothing. I'd not thought about the engine stop/start button would electrically engage the steering lock. I wonder if there's any safety interlock which prevents the steering locking if the car is actually moving when it's operated, or whether it really does lock immediately. Not very sensible if you need to use it as a kill switch for the engine. Maybe the presence of the remote keyfob in the car prevents it allowing the steering to lock, and it only locks once the keyfob is out of range when you leave the car.
If it's all the same with you, I don't think I'll test this the next time I happen to drive a car with keyless ignition :-)
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On Mon, 23 Jul 2018 08:39:20 +0100, NY wrote:

I don't think it does that. I hear the lock engaging when I leave teh car, but also if I sit in it for a while with the engine off.

Yes, although there seems to be a timeout too.
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On 23/07/2018 01:01, Bob Eager wrote:

Good point.
Our Outlander has a 'hold' function which is the closest to a handbrake- and a P position on the 'gear' stick. I'm curious how they will test it come the MOT in 2.5 years or so.
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could be worse....you could have had a chevy Nova when a engine mount broke the engine smashed the power brakes and pulled the accelerator cable giving full throttle......see the world in a chevy nova .....
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Jimbo in Bracknell .... wrote:

New Vauxhall Vivaro van in 2001. Arrived new with no wheel trims, they had all fallen off during delivery. No "special" tool to take the wheels off in case of a puncture. Wiper arm fell off after three weeks. Windscreen seal fell off after three weeks. Sat in van drinking coffee after four weeks, rested foot on the brake pedal and it fell off. Brake pedal, not my foot. The AA bloke said "owwwwwwwwwww". I never trusted that van again.
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On 22/07/18 22:11, NY wrote:

Turning the engine off doesn't lock steering. That only happens when removing the key.
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+1
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On Sunday, 22 July 2018 22:52:30 UTC+1, Chris Bartram wrote:

all the cars I had for decades* DO lock the steering with key in. I gather many don't now.
This is all very 101 stuff though. If someone can't work out what their options are, one can only hope they never have to deal with real life mechanical failure.
* at least the ones that had a steering lock
NT
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On 22/07/2018 23:01, snipped-for-privacy@gmail.com wrote:

While everyone else hasn't.
Rod is always the opposite of everyone else.
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Care to name the make and model? I've had lots of old cars. None *ever* locked the steering until the key was removed. Including the very first one I had which had been fitted with an aftermarket steering lock in the 60s.
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