How To Stop A Runaway Engine?

[sproutdreamer]

The recent case of a renault car having an engine that would not slow down and having to carry on at speeds over 100mph until the fuel ran out in France was a horrifying tale and good that it ended without a major accident. This seemed from what I read to be to do with a cruise control problem. Even the renault techies did not sem to be able to help him when connected by the police. Not sure whether ths was a diesel or not. The well publicized Lexus accidents in the USA also comes to mind.

What interests me is that the renault owner could just not kill the ignition, without removing the key so as to retain steering or just put the car into neutral and blow up the engine-maybe that would explode the engine with more danger to the driver or just change down and damage the gearbox.

The inability to stop the lexus car engines also semed to be connected with the Lexus keyless ignition but I still found it surprising that the driver in the major accident recorded (service police patrol officer) could not do anything.

So my query is:- On a basic, relatively low tech car like an 03 Avensis petrol auto with normal key ignition switch is there a problem in stopping the engine in an emergency by just switching off the ignition but retaining the key so that the steering is still free. Or is there some sort of safety interlock that stops you doing this? Yes I know it would bugger the cat convertor but I am talking about a runaway engine emergency.

[cooper12000]

best thing to do is put it in top stand onm the brake and let the clutch in with a bang ie stall the engine.... prob wont do the car much good but least u dont kill anyone

[sproutdreamer]

best thing to do is put it in top stand onm the brake and let the clutch in with a bang ie stall the engine.... prob wont do the car much good but least u dont kill anyone

I am referring to when the car is travelling at speed, not standing.

[alan333]

Put it in neutral. The drive will disconnect and your engine will continue to rev to it's rev limiter. Sure it will probably blow the engine eventually but the other way round you've trashed your car into a a tree.

Turning the key off should disconnect the electrical input to the engine and therefore only momentum would keep it running. I see no physical restriction on you doing this while in motion.

The only other thing I can think of was on some old old old Ford diesel engines the oilways to allow the oil to return to the sump from the cylinder head were too small, and therefore a "head" of oil built up when the engine was cold. This engine oil flowed into the combustion chamber through the valves. This caused the engine to rev, burning engine oil as fuel, to an uncapped rev speed. The only way to stop this was either to know it was going to happen soon and switch the engine off for a bit until the oil heated up, or to stall it using the clutch and gearbox as mentioned by a previous poster.

Should this happen with an auto box then the only option I can think of would be to put it in neutral and wait until it self destructs.

[sproutdreamer]

Returning to the renault in france incident why would the renault techies not advise this to the driver hurtling along at 125mph?

[cooper12000]

wonders how many cars spoutdreamer has had that this has happened too. maybe the one in france was an auto why didnt the police simply guide him into a runaway slip lane or what ever they r called there. They have em every so many miles in france.

[cooper12000]

these sorts of storys remind me of the one that was doing the rounds a few years ago about this mechanic that decided he wanted to port flow his cylinder head so he connected the air inlet pipe to a bag of sharp sand. then went round the forums asking why his engine was full of sand.

coop

[Cyker]

Re. the Renault incident, it was an unusual case as the car wasn't a standard one but one that had been modified for a disabled driver.

Apparently this is why most of the normal options you'd use for shutting down/disconnecting the engine were unavailable, but it has exposed a pretty hefty safety risk.

For people like us who have unmodified cars, killing the ignition or going to neutral is the easiest thing. The neutral option might not be available to autobox drivers (I believe that most autos won't let you put it in neutral when moving; Is this right?), and the Prius doesn't actually have a neutral gear.

IIRC cars with Start buttons rather than key ignitions won't let you shut the engine down at speed but maybe, like computers, you can hold it down or something to override it?

[sproutdreamer]

these sorts of storys remind me of the one that was doing the rounds a few years ago about this mechanic that decided he wanted to port flow his cylinder head so he connected the air inlet pipe to a bag of sharp sand. then went round the forums asking why his engine was full of sand.

coop

This was not a story-the guy spent over one hour at speeds up to 125mph, the police cleared the roads (including opening up the pay booths at pay stations) and escorted him for over 100 miles until his car ran out of petrol. I still cannot understand how the renault technicians who talked to him on the phone could not advise him how to stop it.

COOP-you obviously never saw the video coverage of the runaway Lexus in the USA where the pasengers are screaming on the mobile phone about being unable to stop the car. All 4 were killed including the driver who was a police patrol officer so presumably a pretty experienced driver!

And yes I had a jammed accelerator once and just turned off the ignition and there was no real problem but that was before high technology maybe makes that more difficult.

[cooper12000]

you have obviously never in all ur 900k+ miles of driving never driven in france or u would remember all the truck run offs

[cooper12000]

this is why i find these sort of things so unbelivable

however as ur so sure of ur self im sure u spent more than .2 of a nano second googleing

[cooper12000]

i guess i find these sorts of things hard to belive because for the cruise to be on it has to be set on.... for it to be set at 125 the car is treaveling at 125 first right. sounds a little convinient to me oh officer i wasnt speeding honest the cruise control got stuck and i couldnt turn it off or just simply deck the clutch or shift into neutral. i susspect the reason people dont turn the engine off is becasuse most cars have power steering and with out the engine running it doesnt work and the steering is !Removed! heavy if u stall coming out of a parking bay or at slow speeds no matter "stall" at 125 its an issue.

[sproutdreamer]

you have obviously never in all ur 900k+ miles of driving never driven in france or u would remember all the truck run offs

Drove to Dolomites, French Alps, Swiss Alps,Vercours, Verdun, Pyrenees etc each year for 20 years plus winter skiing trips. I think you would have to be very brave to drive into a sand run off at 125mph. From memory the run offs tend to be common on the alpine roads but not so many on the (straight) motorways.

[cooper12000]

would rather drive into a sand trap than hit a wall or another car/lorry etc least the sand would slow u some what b4 u hit anything.

then again i would of pulled onto the hardshoulder and decked the clutch long b4 i needed the run off

[Roker]

I have heard about this with diesels, where the lube oil leaks from the turbo and the engine runs away burning lube oil.

[cooper12000]

the difference with that is that the engine carries on running on the oil from the blown turbo seals so even if u switch the engine off and take the key out it keeps going... however all u have to do is once ya stationary with the key out shift into top stand on the foot brake and dump the clutch to stall the engine.

however there is a debate going as to weather it actualy happends because if the engine ran on any old oil no one would have to buy diesil;)