Self Destruct !

[mbunting]

So, I'm on my way back from the supermarket, when I see smoke accross the road where there's a layby. Interested but not concerned, because opposite there's a guy with a big traction engine and he tends to load / unload it in that layby.

As I get closer, I can smell oil.

Then the noise - about 8,000 rpm I'd say

Then I see one of britains finest ( except this example, obviously ), a Range-Rover, probably mid 90's vintage I would say, not old but not new.

The only thing for certain now is that it'll be dead !

The ( assumed ) owners were stood nearby, and they'd helpfully parked it about 2m away from a mondeo in an otherwise empty 300m layby..

First time I've ever seen that - even though I know it can happen. Wonder if it was an auto... can't be stalled.

I was wondering though, if you took the keys out, and set the alarm, would the immobiliser kick in and stop the spark ( in a petrol ). Obviously a diesel would not be able to do this...

[citronut]

they are probably trying to run it on parafine,many years ago i borrowed the firms ATLAS van to take a mogy engine to my brother inlaws in canterbury,pulled onto the roundabout out side the cop shop and it cut out,so i rumaged through the back of the van found an old metal shell petrol can with a cup full of something in it,poured it in the tank started up it got me the the filling station where it would not shut of,so i had to stall it,turned out i had stuck parafine in the tank
regards malcolm

[Homer]

I was wondering though, if you took the keys out, and set the alarm, would the immobiliser kick in and stop the spark ( in a petrol ). Obviously a diesel would not be able to do this...

If it's a petrol then turning the ignition off should stop the spark but that's only any use if the engine is relying on the spark to run.

If it's an electric fuel pump then that would also cut out.

[alan s]

This sounds very much like a problem exclusive to diesels with grotty intakes. We used to get a few posts about it a few years ago, but lately, possibly due to advances in engine/injection designs, I haven't heard much of as late.
It can come from a variety of causes including oil accumulation in the air cleaner, oil getting into the turbo and also into the breather system.
As we know (since the advent of running them on cooking oil and bio diesel) the diesel engine seems to be able to run on a wide variety of fluids and as dieseline is oil based, any source of oil based product or volatile vapour will cause them to operate. It seems given the right set of circumstances, these vapours/fumes will get into the system and the engine will run happily on these fumes, usually after the key has been turned off and hence the normal source of fuel has been shut down. As the "outside supply" of fuel diminishes, it increases its level of oxygen in the mix and creates the equivalent situation of flooring the accelerator which then has it sucking harder and hence digging every last scrap of material that will feed the engine and will continue to do this until the engine disintegrates in spectacular fashion as by this stage it is totally out of control. Switching keys off, disconnecting shut off valves, immobilisers etc will have absolutely no effect.
I first heard of it a few years ago (remembering that I live in a country where there'd be lucky to be 5% of cars sold which are diesels) when a rather shaken mechanic had taken a Toyota Hi-lux in for a small service. When finished, he started the engine and had it running in the workshop when it suddenly began to rev. He did everything possible to stop it all without luck and was climbing in to drop it into top gear and drop the clutch when "she went bang!!"
I didn't envy him the job of trying to comvince hios customer that he hadn't revved the guts out of it and blown it up in the process.
The moral of the story is, don't try to get a million miles out of each oil change and keep the intake and breather side of the system clean.
(That should have a few running out into the darkness checking under the bonnet)


Alan S

[mbunting]

Presumably another way to stop it would be to attempt to block the air intake enough to stop the combustion..

I'll be passing that area today, so I'll look for signs of cambelt / chain, pistons etc.. on the road

Didn't this also used to be caused by over-filling the sump with oil ?

[alan s]

Strangely, I understand blocking air off has no effect due to the source of the fuel which is already mixed.
Overfilling the sump was another way of having it happen too I understand.


Alan S

[nick]

Apparently a sure way of stopping a runaway diesel engine is to spray a CO2 fire extinguisher straight into the air intake. Problem is not many people carry large CO2 fire extinguishers around with them!

[SteveG]

This is a known issue with Land Rover 200 & 300 Tdi turbo diesel engines - not common, but not unheard of. It occurs when either the turbo seals fail or the engine has too much oil in it and it starts to feed off itself. Nasty ... normally terminal

Being a Rangie it was almost certainly an automatic. Unless the driver realises what's happening and manages to get it into gear before the revs get above about 800 the rev interlock will prevent gear selection and bang goes any chance you've got of stopping the engine ... and bang goes the engine too.

I've seen it a couple of times and it ain't a pretty sight.

[philhoward]

I had a similar situation with my old BX 19RD..washed the element with petrol, but it must not have been totally dry when I refitted it..Luckily it used all the "vapour" before it went above what must have been about 4000rpm. Most worrying when (it was my first diesel) you turn off the ignition and it still keeps running..

Was still running fine about 20,000 miles later when I sold it. Have always pulled the inlet pipes off subsequent diesels and wiped the excess oil of out them at every service just in case.

[KP]

Will happen on any TD engined car when the turbo seals start to let go or the oil vapour doesnt recirculate correctly.

Was on scrapheap challenge a fair few moons ago where one guy, farmer type, was playing with a HGV engine governor and messed it up and i think he only just saved it by shoving a jumper down the intake... not a good idea but always a good reason to keep a rag in the boot

[Stewart(oily)]

I had the same thing on a BX 19RD a few years ago, I bought an electric sump pump in France and got into the (BAD) habit of putting one pipe down the dipstick hole, the other into a 25 litre waste oil container and switching on, then getting on with something else for a bit, these engines hold 4.5 litres with filter so my practise was to just pour a whole 4.5 litre can straight in, unforunately the pump was broken, still running you understand, just not pumping, I was driving down the local dual carriageway when a sound not unlike a petrol engine pinking was heard the car began to accelerate, a glance in the rearview mirror revealed a total whiteout, turning the ignition off did not have any effect, I braked the car to a stop in fifth gear, drove very gently home and took the excess oil out no damage that time On my old landy defender the dipstick was marked LOW...HIGH....DANGER, now we know why
Stewart

[pug_owner2002]

I saw an 06 plate Laguna a few weeks ago in this state on the hard shoulder of the motorway.
From a distance it looked like the car was on fire due to all of the smoke but once I got closer I could see all of the smoke was billowing out of the exhaust and the engine could be heard revving away.
In amongst all of this you could see the occupants of the Laguna retreating up the embankment.

[reblack68]

I think that's a bit of a known issue on Lagunas, caused by the EGR valve leaking or something like that. It's one of the reasons for their spectacular depreciation.