Runaway Cars

[norseman]

What is the title of the thread?

Not so much the title itself, more about what it actually means .. a diesel engine that over-runs the governor & revs. to destruction. Often running in reverse, burning engine oil & breathing through the exhaust, which means the 'stop' control has no effect.

You have to be of a certain age to remember these events

 

[Stivino]

You have to be of a certain age to remember these events

What age do you think I am as you seem to assume that I won't know about "these events"?

 

[norseman]

What age do you think I am as you seem to assume that I won't know about "these events"?

I have no idea & it was not my intention to cause any offence. To me the wording of your post appeared to infer that you were unaware of what the phrase meant & as these engine problems occurred decades ago (certainly in my experience) you may not be familiar with the phrase.

 

[Stivino]

I have no idea & it was not my intention to cause any offence. To me the wording of your post appeared to infer that you were unaware of what the phrase meant & as these engine problems occurred decades ago (certainly in my experience) you may not be familiar with the phrase.

The fact that I stuck with the thread title is no indication of my lack of knowledge.

 

[norseman]

The fact that I stuck with the thread title is no indication of my lack of knowledge.

So should I have assumed your initial post (#11) was simply repartee?
If I had done so I would have given you a 'like'

 

[Avocet]

It's possible to guard against it by putting a spring loaded flap in the air intake. If the engine runs away the suction is so great that it overcomes the spring and the flap shuts off air.

Technically quite difficult, I'd have thought? You'd need to let it flow enough air for maximum power to be achieved, but not so much that under no load, it prevents over-revving?

My dad's old Xantia had a few "diesel runaway" episodes before it finally died. On each occasion, it was stopped by grabbing the flexible induction hose on the way into the engine, and squeezing hard. He was thinking about installing a flap such as you suggest (a spare butterfly out of a petrol engine throttle body in fact), but connecting it to a choke cable, so he could just pull it manually from inside the car, if the engine started to run away, but he never got round to it before the car was scrapped.

 

[Avocet]

There's always runaway cars. Normally it's driver error (cans stuck under pedals etc.)

Sometimes it's more systematic, eg factory floor mats that can get stuck.

Once it was bad computer control code. Toyota had some particularly bad stuff that's fairly infamous in IT circles.

It is normal to try not to talk about it as if you have to explain why you're confident your vehicle is not going to drive you into a concrete wall at 110mph you've already lost the sale.

Yes, that's the thing. As soon as a manufacturer says publicly: "There! You see? It wasn't our fault after all!", he's lost. All he does is alert everyone who hadn't heard about the incident, to the very thing he's trying to avoid drawing attention to, whilst at the same time, everyone who does know about it, will wander off saying "no smoke without fire..." - or as Shakespeare (almost) put it: "the manufacturer doth protest too much, methinks"...

 

[norseman]

My dad's old Xantia had a few "diesel runaway" episodes before it finally died. On each occasion, it was stopped by grabbing the flexible induction hose on the way into the engine, and squeezing hard. He was thinking about installing a flap such as you suggest (a spare butterfly out of a petrol engine throttle body in fact), but connecting it to a choke cable, so he could just pull it manually from inside the car, if the engine started to run away, but he never got round to it before the car was scrapped.

I had no idea that this problem could still occur with relatively modern diesels, especially as I have owned a Xantia myself & never experienced anything remotely like it.

You live & learn

 

[Avocet]

I had no idea that this problem could still occur with relatively modern diesels, especially as I have owned a Xantia myself & never experienced anything remotely like it.

You live & learn

Yes, any diesel has the potential to run on its own oil mist. It's more common with elderly ones (this one had well over a quarter of a million miles on it), where the crankcase pressure is higher because the rings are worn, and the turbo seals might be leaking a bit. Anything that allows oil mist into the inlet tract can cause it.

 

[ericmark]

Run away diesal engine I had I was able to stall. But since manual it could not cause the wagon to run away.

Have seen generators with flaps to stop runaway. Not seen them on road vehicles.

Most autos I have driven one can select neutral and brakes are better than engine so even if engine runs away, the vehicle will not.

Run away train yes, when depending a gradient on a goods train one may need to latch on some of the wagons brakes first, not stopping to do this can cause a Run away.

But I think one reported was an EV. I know with the 8 speed Jag auto the drive selector can retract, so one may not be able to select another drive option.

Only runaway I have had was a push bike, going down Simons Yat, the disc brakes are worked by a cam, and one at end of rotation it will not push any harder, so brakes seem to be A1 until you need to push hard on them, and it does not matter how hard you pull on them just the same retardation. Lucky nothing came up the hill, at bottom discs were blue, so easy to adjust with Alan key, but did not realise out of adjustment.