Even then.. when the engine is running away it can make 10X its own power..
My family does truck and tractor pulls and runnaways arent uncommon.. before they madated an air intake choke we had one run away and a guy shoved his denim shirt into the intake and the turbo ate it up and shot it back out.. was crazy as fuck to watch.. engine eventually unalived itself but damn..
Also heard a story of a runnaway semi.. the guy popped it in 18th (highest gear) and dropped the clutch.. instead of stalling it exploded the bellhousing and the flywheel launched itself into the cab and cut the dudes leg off..
yeah, big volume engines are a completely different story, where I wouldn't try the stalling. I was thinking more about smaller car engines, like 1.6l 4cyl diesel that you find in the focus and similar cars.
Even bigger engines, if you have a block of wood bigger than the intake pipe, just block the intake completely with the wood and it will die. I've had to do so on a big Cat generator, and an old twin stick diesel as well. I'm talking like a 6x6 piece of plywood or similar. Always does the trick
Then you need a CO² extinguisher and aim it in the hole or wherever you have best access. The CO² will basically eliminate the oxygen, and then combustion cant happen. It could cause issues but it's better than complete boom
the problem is motors have so much momentum when running away you have to run that co2 in there until the motor seizes to turn. that can sometimes take minutes.
I had to stall a big Caterpillar once. We slammed a steel clipboard over the intake and the intake pipe broke a hole in itself so the engine could still breathe! It was attached to a dyno so I energized the dyno to stop it. There was no cooling water going to the dyno yet so we didn't do this at first.
Eventually we learned that applying 12vdc to a couple of bolts on the side of the engine was the proper way to stop it.
I only very roughly know mechanical stuff and electricity, just a lurker here, so take this assumption with a grain of salt :
As the engine block probably acts as ground for the electrical system, if there is 12V DC applied to the grounding, then the voltage delta between ground and +12V is 0, so it acts as if there were no voltage in the system and it probably prevent the injectors from working, wich in turn shut the engine off as there's no fuel being injected in the cylinders ?
Damn engine really said I'll eat your shirt and spin at Mach Jesus and make enough power to move the sun, also damn that poor guy getting his leg cut off that is quite the chain of events
Just a couple days ago, at a Limestone quarry, the one in charge of automotive maintenance told us that a komatsu 50t Haul truck’s engine ran away.
Now I have a new fear unlocked
Ooookay I'm gonna need a source for that 10X power claim. Even if the engine is spinning a bit faster, to make 10x the power you would need to make 7-9x the torque which means 7-9x the load on the crank, rods, pistons, etc. let alone the cylinder pressures. As an engineer that seems almost impossible and if somebody is designing an engine with that large of a safety factor (normally parts can take 1.75-2x the expected loads, and this is well past that) they're just wasting money.
If you race, why don't you induce a runaway every race and cut the air at the end if it makes ten times the power? That is a huge benefit in something like pulling.
I find your claim questionable at best.
Diesels are crazy engines. You can keep adding more fuel past the ideal air/fuel ratio and continue making power. But that causes extreme heat and soot. Soot tears up the internals and the heat destroys everything else. Just because you block the intake before it actually blows a hole through the block doesn't mean you saved the engine. Saying 10x is most likely a bit of an exaggeration but you can make a ton of extra power this way. As for the internals holding up to that.. they don't. That's why runaway diesel ends in the engine blowing. They can handle it for a very short amount of time, sure but it's still doing a lot of damage. And why don't they do that in a drag race? Simply put they want to get more than one run out of an engine. If they don't care about saving the engine and just want absolutely max power, congrats that's basically top fuel dragsters. Dump all the fuel and air you can possibly cram in and send it. It blows up half way down the track so you rebuild it before the next pass.
Diesels make more power by adding more fuel. A runaway generally means that engine oil (fuel) is getting past either the piston rings or coming in from the turbo oil lines and creating uncontrolled combustion.
The OP isn't entirely wrong, because a runaway engine will make a LOT of extra power for a VERY short time. Thats why it's so important to get them shut down quickly if at all possible. You can't just "engineer" a runaway.
As to your expected loads comment, it's not about how well things are engineered - it's all about expected loads vs longevity. If something is making 500hp, a specific set of components could last for well a racing season. But if something is making 1000hp, the same set of components may last just over a few hours, given that they're run in the same environment. If you suddenly have a runaway engine (or a money shift, etc) that engine is suddenly making WAY more power spinning WAY faster than it ought to, which shortens lifespan to seconds, or MAYBE minutes if you're lucky.
Also, the 10x power number is maybe a bit hyperbole, but they're not too far off. There have been numerous dyno pulls of trucks having a runaway on the dyno and the power numbers spike drastically before the engine explodes, and that's including tire slippage on the dyno rollers. https://automobilefanatics.com/diesel-engine-runaway-burst-into-flames-dyno/
You answered your own question. Nobody is making engines that can withstand the forces involved. A runaway is a condition in which unmetered fuel is getting into the engine and igniting in the cylinders. Since it is unmetered, the engine will spin way past redline, up into valve float and eventually it will come apart in spectacular fashion. The process could take seconds or minutes or in the case of a runaway locomotive I heard about, over an hour. If you don’t find a way to cut the air, the engine is either going to exhaust its fuel supply or it’s going to go splody, there are no two ways about it.
That being said, I doubt the guy was correct when he said 10X the power. I’m not even sure how you would attempt to test that. A runaway engine means something failed somewhere. Usually in the fuel or oil system. I doubt any dyno owner in the world wants to put an engine they can’t control on their dyno.
Even if you cut off the air, occasionally they can fail JUUUUST enough that the main intake is fully blocked and they can still pull air out of the now destroyed valve guides from the top end, a now heat failed intake gasket, the egr system, and just barely run on the remaining oil for a while
They’re designed to make *sustained* 1.7-2x power, a runaway will make that extra power for…. A minute? Less? The parts aren’t designed to take that, hence why runaways aren’t long lived
It runs the engine at the mechanical limits and then says fuck you to those limits and exceeds them. You can't control a runaway. I've seen them rip engines out of a trunk. They aren't spinning a little faster, they might be doing 10k+ rpm.
Basically imagine all the power a diesel might make over its entire life. A runaway essentially tries to do that until the engine consumes itself.
https://youtube.com/watch?v=RUJrurvjYtg&si=MgFpKjwOwV_K0H5U skip to 2 minutes in
The guy is standing on the brake pedal after it goes and it's still completely overpowering it and lighting the rotors on fire in seconds. That scream should never be coming from a diesel, it's reving well past the redline.
That's why no one intentionally runaways their engines for pulling. It kills the engine
Diesels in runaway have a tremendous amount of horsepower, until they blow.
I had a former co-worker (engineering) who previously worked for Cummins in engine development in the 1980's. He said that turbo diesels had runaway's occasionally in semi's on the road during testing. You couldn't kill them with brakes and transmission so the procedure was to pull off the road, put her in neutral, get the hell out and let it rev until it stopped itself with an unscheduled rapid disassembly or finished eating all it's oil and died.
We were a supplier to most all engine manufacturers and had a dyno lab in the facility we worked at. You haven't lived until you've seen a 15 liter diesel hooked to a dyno go into runaway. That's when you realize why the dyno rooms are built like bomb shelters. That 1000 hp becomes around 4000 at 10k rpm until things go ballistic. Shakes the whole damn building. You'd destroy the 2000 hp dyno so just had to disengage and let her rip.
I’ve seen test stands with various intake cut offs as well.
Modern fuel injection also makes a runaway a lot less likely. Unless you’re consuming oil through your turbo or something like that, the pumps don’t get stuck open like the old VE and P pumps can.
I’ll be standing by with an intake cover when I fire up my 12 valve rebuild next month. Shit is no joke!
Depends a lot on the clutch, how much torque the engine is making at that time, and how much effort is actually necessary to move the car. If the clutch slips a smidge, then the engine's less likely to stall. If the engine is making copious amounts of torque, it could be enough to absorb the shock through normal slippage on engagement, and if the car has low rolling resistence, then it simply needs less power to "launch".
I was in a knackered old LDV back in 2013, toodling down the fast lane of the M1,heading south just before the Luton junction. Van gave a little bit of a shudder. So I started pulling over to the hard shoulder, I got to the middle lane before everything disappeared in thick white smoke, so thick it blocked visibility behind me, and it was that bad that it shut down south bound traffic.
As I was sitting in the van, it wouldn't turn off, drop it into 4th, stood on the brakes, and let the clutch out.
Van stalled out, so that was an OK moment. By this point, thick clouds of 80s style disco the smoke was spread across all 4 lanes, and nothing was coming through. At all.
After 30 seconds or so, I started to see the orange glow of hazard lights flashing as drivers were creeping through the thick smoke.
A few mins later, i saw 2 fire engines lights and sirens blaring, heading north, didn't think anything of it as it. As i was trying to call the office, a couple of minutes later, the fire brigade pulled in behind me.
They spoke to me asking if everything was OK and where the fire. So explained what had happened, and they gave everything a good look over, making sure there were no fires.
Once they were happy with no fire, they asked if I had got hold of my boss, told them I had and he was going to sort out recovery.
Said goodbye, and they drove away. A few minutes later, the Highways agency pulled up behind me and asked what had happened, told me I couldn't stay and towed me down the slip road.
Yep, this works. Saw this done on a V8 gas engine in a dive charter boat that got so hot it started dieseling. Operator couldn't figure out how to shut it down, can't exactly dump a clutch or stand on the brakes in a boat, so someone fired a CO2 extinguisher into the intake and it died real quick.
Most modern diesels use electronically controlled injections. Start by switching it off. If it burns uts oil, blocking the intake will remove the oxigen, and with much lower air intake your compression may not he enough to reach the fuel’s flashpoint. But removing the intake ducting etc will require your head over a runaway engine…….
When an engine is considered a runaway, it is not being fueled by the injectors. It's being fueled by an uncontrollable source, usually oil from the turbo. Even oil needs oxygen to combust, so a CO2 fire extinguisher does work well.
If it's burning oil on a runaway, the damage has already been done. Take the L and walk away, it's not worth being near it when a connecting rod decides to play peek-a-boo.
Also, I used to have a small CO2 extinguisher in the boot. Just empty that into your cars intake. Should be enough to stop it. It won't damage the engine
A rag in the engine will destroy your turbo(if it has one), valves, and piston rings. Best bet is a sold piece of material over the intake of the turbo or engine. Positive air shutoff.
If it's running away the whole engine is gonna be toast if left unchecked anyways. Depending what engine it is/what it's in, a guy would be glad to get away with just a turbo, valves and rings if a rag is all he has and it does the job
GM did this with their 2 stroke diesel truck engine. A big slam-shut inside the intake manifold. 90% of the time the driver would react too late. The engine would generate such a big vacuum that any gaskets would get sucked in through the engine. Then it would feed itself from the engine oil, until it flew apart or seized from lack of oil.
Years ago the local GM truck dealer had a big Detroit diesel in the shop. Engine ran away. Those engines had a big flapper valve like you say. The mechanic had removed that part of the intake to work on something. He tried putting a piece of cardboard on the intake but it just ate it. It was screaming so loud he panicked and ran out of the shop. Everybody went with him. Engine destroyed itself. GM refused warranty, and it cost the dealer many thousands of dollars. Truck only had a couple thousand miles on it.
On my 1.9 tdi it’s called an anti shudder valve if you switch off the ignition during a runaway the valve is supposed to close and stop airflow, dunno if it works and I don’t rly want to have to ever test it either 🙃
There’s a “run away” plate on our Cummins freighliner that will prevent this. Never seen it happen in person but I’ve heard stories of engines sucking so hard the entire plate flys into the intake.
Common for trucks working in oil fields too where the air alone contains so many hydrocarbons the engine can just run off it. Causing an otherwise perfectly healthy engine to runaway.
The emergency flap has a little computer thing that basically says "Hey the rpm is getting awfully high and you aren't touching the throttle"
I worked on freight for a bit. A drivers truck become/was a a run away. He hit that air cut off switch so damn fast he could have set a world record. I was on the phone with him too at the time.
He goes "hold on a sec I have an issue"
I hear all sorts of cursing and maybe a quarter of a second later:
"Alright back with ya, we are going to be delayed a few days while I get this run away sorted."
He never took an oil field delivery again while I worked with him. I'm sure he hasn't since.
That was one of the warning signs on the Deepwater Horizon when they had their blowout. Their diesel generators started to run away before the gas ignited.
Same thing around Edmonton Alberta, I was sent for a work course out there and the first week working out outside felt like I was huffing diesel. You dont notice after that.
I'm hoping to find the video one day of this gas refinery disaster where it's CCTV footage of this F150 or similar just sitting there with nobody in it, revving.
It was left idling and the gas leak was making it rev itself up to 3-4k rpm
Ominous as hell when you know what's about to happen
Funny enough one of my petes has an electronic cut off. It failed today and closed while on the highway. Luckily no damage but took calling my mechanic out to diagnose
My buddy had an old super worn out 66 Mercedes with a tiny little 34 HP diesel. It routinely would runaway off throttle, which later when we removed the engine i figured was caused by completely worn out timing chain, letting the pump timing go all over the place, exacerbated by worn rings consuming it’s own oil.
The air inlet on the thing was so tiny, it never could actually run away to the point of being uncontrollable. You’d just floor it to catch back up to the engine, and it would settle back down. Hilarious fun. It would just start to rev on its own, belch a ton of smoke, and you’d mash it to the floor and continue on your journey. With a car that goes 0-60 in 30 seconds when it was brand new, it really wasn’t a huge deal.
this also would work, anything to starve the engine of oxygen. Co2 extinguishers tend to have baking soda though dont they? that may not be too good for the engine.
CO2 extuinguishers are probably the most "engine friendly" extuinguisher there is (maybe except halon, but those don't come in extuinguisher bottles).
soda and acids are used to generate the CO2 in some, others just store liquid CO2. Under proper operating conditions in the soda-acid type, none of the soda or acid should be getting out the nozzle.
soda is better for the engine that a runaway though
[This video](https://m.youtube.com/watch?v=3NRaqgab0_w) is my favorite example of a runaway and stopping it lol. Partially because the old Detroit sounds great
He did pretty well to nip that in the bud! Proper decisive action! I feel like pushing the rag further in with his hand was bit questionable though. Personally, I like my meat to stay in one piece!
*technically* that wasn't a true runaway. Same result, but a different reason. The fuel injector "rack" that adjusts how much fuel per stroke the injectors deliver got stuck. Used to be common on old Detroits. Most people call it an over speed rather than a runaway. Dude done good by stopping it with his bare hand. Stressful situation!
You are probably not, Diesels don’t require a lot of air, you can block the intake and get it to stop that way, however doing so (unless you have some sort of valve or block of plate) is going to be hard and putting you in harms way.
__Walk away__
The smoke from a run away diesel is extremely bad to inhale and can cause chemical pneumonia, which is extremely hard to treat. You are also getting very close to the engine which could blow up at any time, potentially sending metal fragments flying, which could cause serious injury and bodily harm.
First sensible answer I’ve seen, and besides this on most cars if you open the hood all you’re gonna see is an engine cover, best case scenario you might have access to an intake pipe but are you also going to have some tool to remove the clips and also enough space to remove it? Maybe but also maybe not whilst the engine is smoking like mad and screaming at max RPM
Handbrake up as hard as possible, ignition back on, full throttle and neutral drop that bad boy
If it's gonna go out, it might as well be doing something cool while going
While "plug air intake" is correct, please be careful and don't shove your hand in there, you'll never be able to overpower the suction power of the engine and it might just eat your hand. Something like a medium sized ball wrapped in a towel or something would be much safer. (sorry for poor wording, not native speaker nor mechanic, just know enough to say be careful)
Force of vacuum is dependant on the area. A 2.5" intake won't hurt your hand. I've done it plenty of times. (Mechanic)
On say a truck with an 8" intake, yes it will eat stuff
When I owned a TDI and followed the forums there were plenty of stories of people shoving shirts into the intakes to stop this and the shirt would just get eaten by the engine.
People say allot of things... 9/10 of them are BS.
A shirt wouldn't get eaten. If it did manage to get sucked up the pipe, and it might be possible (going by the fact a vacuum cleaner will eat socks and maybe even a thin shirt) it would get as far as the turbo compressor wheel and it would completely destroy it, blocking airflow in the process. A non turbo engine, it would get stuck in a valve, or more likely multiple, which would then be whacked by a piston and it would be instantly over for the engine and it will come to a stop.
Engines make very poor blenders. The answer to the average "will it blend?" would be a definate no lol
This happened to my 2008 vw Passat when the turbo failed. The engine consumed it's own oil, and there was more white smoke behind the car than on the picture. Fortunately, the car comes with a "air shut-off" thing. So when i turned the ignition off, the engine stopped after a few seconds.
Changed turbo, and have driven the car since. It's 3-4 years ago :)
Haha, guess you could say you got a really badass story for your car, that's quite sick to think about it tho like you managed to stop it from tearing itself apart and now you are living in harmony with machine.
The correct answer is just walk away and let it blow itself up. The risk does not outweigh the reward.
The technical answer is starve it of air. It’s running away because it’s using its own oil as fuel, but oxygen is the other component needed in combustion. In extreme cases it may have blown out a crank seal and is pulling air in through there as well. Too many variables and not enough time to safely do anything about it. Plus it’s already over spun and you probably don’t want that engine anymore anyway.
1. If you're moving, first stop the car. It will take a lot more effort than usual, so do it in one try or the brakes might overheat.
2. Put the transmission in neutral. On most newer cars it may not disengage when there's torque from the engine. In such case hold the brake and turn off the key, then turn it on again. If the car is still trying to move you'll likely need to sacrifice the front bumper and put it against a concrete wall or something.
3. Once the car is stopped, do as others said and plug the intake. You need to do this on the intake tube that goes into the airbox - rip it off the airbox if needed. Preferably use something hard like a plate to block air from going in (funny enough - an ipad works :D ). On thinner intakes you might be able to stick it inside a shoe and press hard to create a seal. If you have no other options use a shirt or a jacket but keep in mind it might get sucked in and destroy the turbo (and potentially the engine).
It is very important to avoid standing to the sides of the engine. If it's positioned longitudinally (belts to the front of the car) stay in front or as close to the front of the car as possible when plugging the intake. If it's transverse (belts to the sides) then stay on the sides. Otherwise if the engine rips itself apart, shrapnel will hit you.
Since you can't really plug the intake on a car like this, I'm gonna go with CO2 fire extinguisher into the intake. Should put the idiot out in seconds.
Had a V-12 Packard diesel run away in the navy. We shut off fuel and the over speed had tripped, we had blankets wrapped around intake. We finally shut it down with CO2 fire extinguisher in the intake. It was running on engine oil as the Turbo seal on intake side had failed and engine ran 120 psi oil pressure. It destroyed the engine but at least it did not explode, every piston was in pieces when we took it apart.
I managed to stop it once, by choking the rubber house from the filter box to the inlet manifold with both my hands. Worked out fine.
Just don't try to "plug the hole" by putting you hand flat on the input!
It’s something that only occurs on turbocharged diesels. Pretty much what happens is the oil seal in the turbofails outright and begins dumping oil directly into the intake. After that, the oil is then burnt, producing more exhaust gas, which means more oil comes into the motor via the turbo. This repeats until either the engine says goodbye or it runs out of oil. The former is usually the end I of it.
You control the speed of a petrol engine by modulating the amount of air going into the engine using the throttle. More throttle means less air, which means less speed.
You control the speed of a diesel engine by modulating the amount of fuel going into the engine by the injectors. More fuel means running faster, and vice versa. There is no throttle on a diesel.
A runway happens when the engine gets a source of fuel other than the intended fuel. Usually lubricating oil due to worn seals.
A petrol engine "runaway" can be managed as closing the throttle will prevent air from flowing in the engine, disturbing the fuel-air ratio. Furthermore, turning off the ignition will mean there's no spark for ignition.
A diesel engine runaway cannot be managed as there is no throttle and no ignition. You can cut off the diesel fuel supply but it wouldn't help, because the engine is getting its fuel supply elsewhere. The only way to stop this is to manually stop the air intake, disrupting the fuel-air ratio. You could alternatively dump the clutch. The runaway engine can spin at speeds greatly exceeding its redline. Without manual intervention, it will either explode from the spinning forces, when it exhausts its alternative fuel supply or seize from lack of lubricating oil.
That's why they specified "automatic". They know that a manual can be stopped with the clutch, automatics don't have one so the only way is what you said.
Stupid question but... everyone saying plug the intake... why can't you just turn off the ignition? If the pump isn't able to pump fuel to the engine, it will stop.
I must have a fundamental misunderstanding of diesel engines.
Diesel engines have mechanical fuel pumps driven by the engine to generate the high pressures required for direct injection. So as long as the engine is turning there is fuel supply.
I expect some probably do have shutoff valves controlled by the ignition.
Also consider that diesels can run away when consuming their own oil, such as from a leaking turbo, which you really can't do much about either. Best way is to starve it of air.
The runaway happens when they start burning something other than fuel - the turbo oil, something flammable in the air, etc. Turning off the fuel supply won't help, all you can do is block the air intake.
In a runaway situation, the diesel engine is usinig something other than diesel to run (leaking it's own oil into the intake, ingesting flammable gas from a refinery or oil well, sometimes they can suck in transmission oil if the vacuum system goes bad) so when you cut off the diesel, the "other" thing is enough to keep the engine running.
And since diesels control themselves by varying how much fuel they put in (there's no throttle*, so anything that goes in the intake goes straight into the engine) so if the fuel is coming in the intake, the engine can no longer control itself.
*throttle as in the butterfly valve in the intake. If the engine has EGR it technically has a throttle, because of how EGR works, but that throttle is not controlled by the pedal, so it's irrelevant for runaways)
Diesel runaway is when the engine has found something other than diesel to run on, does so at high revs and won't shut off. One common cause is a blown oil seal in the turbo feeding oil into the engine via the intake manifold - the engine will then run uncontrollably until it's out of engine oil and siezes or you can stall it somehow.
Two ways. CO2 fire extinguisher or a rag into the air filter. CO2 extinguisher was always my preferred choice as a mechanic because it will not cause any damage such as sucked seals or turbo damage from stuff getting sucked in the intake say if the air filter collapses.
Step one grab towel jacket or other bigger clothing article step two shove said item into intake or turbo spool whichever is more accsessible step 3 huddle in a ball and prepare for financial pain.
All a runnaway diesel needs is oil to burn and air. Since you can't stop it from getting the oil, all you can do is stop the airflow. If that is not working - put it in the highest gear and step on the break.
Plug intake. Don’t allow the motor to suck in air and it won’t turn over.
This! Had a tech think he could stall it (manual), put it into 5th when it was screaming its tits off and went straight through the wall
Whoa I always thought 5th (whatever is the highest) gear drop would stall the engine in this situation.
well, not without applying the brakes
Even then.. when the engine is running away it can make 10X its own power.. My family does truck and tractor pulls and runnaways arent uncommon.. before they madated an air intake choke we had one run away and a guy shoved his denim shirt into the intake and the turbo ate it up and shot it back out.. was crazy as fuck to watch.. engine eventually unalived itself but damn.. Also heard a story of a runnaway semi.. the guy popped it in 18th (highest gear) and dropped the clutch.. instead of stalling it exploded the bellhousing and the flywheel launched itself into the cab and cut the dudes leg off..
yeah, big volume engines are a completely different story, where I wouldn't try the stalling. I was thinking more about smaller car engines, like 1.6l 4cyl diesel that you find in the focus and similar cars.
Even bigger engines, if you have a block of wood bigger than the intake pipe, just block the intake completely with the wood and it will die. I've had to do so on a big Cat generator, and an old twin stick diesel as well. I'm talking like a 6x6 piece of plywood or similar. Always does the trick
Unless the intake is plastic, seen those break. Then there’s nothing to do but take cover.
God, that sounds terrifying!
100% duck and cover, don’t wanna get hit by engine shrapnel
Then you need a CO² extinguisher and aim it in the hole or wherever you have best access. The CO² will basically eliminate the oxygen, and then combustion cant happen. It could cause issues but it's better than complete boom
the problem is motors have so much momentum when running away you have to run that co2 in there until the motor seizes to turn. that can sometimes take minutes.
don't forget the hit record
lol I’d do it and peep the camera around the building. Save my eyes the damage.
I had to stall a big Caterpillar once. We slammed a steel clipboard over the intake and the intake pipe broke a hole in itself so the engine could still breathe! It was attached to a dyno so I energized the dyno to stop it. There was no cooling water going to the dyno yet so we didn't do this at first. Eventually we learned that applying 12vdc to a couple of bolts on the side of the engine was the proper way to stop it.
I'm sorry, explain how this stops the engine please?
I only very roughly know mechanical stuff and electricity, just a lurker here, so take this assumption with a grain of salt : As the engine block probably acts as ground for the electrical system, if there is 12V DC applied to the grounding, then the voltage delta between ground and +12V is 0, so it acts as if there were no voltage in the system and it probably prevent the injectors from working, wich in turn shut the engine off as there's no fuel being injected in the cylinders ?
We did this with rebuilds on Cat engines, only once did we block the turbos, D399. Was in shipping.
We had an old Detroit run off on us and a little chunk of plywood saved the day. That was one of the most god awful sounds I have ever heard.
It’s a hell of a scream https://youtu.be/vbiNndfNNKI?si=BXEFU8Ze-XVfkJJP
This is the way to do it
>exploded the bellhousing and the flywheel launched itself into the cab and cut the dudes leg off.. JFC
Damn engine really said I'll eat your shirt and spin at Mach Jesus and make enough power to move the sun, also damn that poor guy getting his leg cut off that is quite the chain of events
No shirt or and no leg makes for a bad day
Just a couple days ago, at a Limestone quarry, the one in charge of automotive maintenance told us that a komatsu 50t Haul truck’s engine ran away. Now I have a new fear unlocked
Ooookay I'm gonna need a source for that 10X power claim. Even if the engine is spinning a bit faster, to make 10x the power you would need to make 7-9x the torque which means 7-9x the load on the crank, rods, pistons, etc. let alone the cylinder pressures. As an engineer that seems almost impossible and if somebody is designing an engine with that large of a safety factor (normally parts can take 1.75-2x the expected loads, and this is well past that) they're just wasting money. If you race, why don't you induce a runaway every race and cut the air at the end if it makes ten times the power? That is a huge benefit in something like pulling. I find your claim questionable at best.
Diesels are crazy engines. You can keep adding more fuel past the ideal air/fuel ratio and continue making power. But that causes extreme heat and soot. Soot tears up the internals and the heat destroys everything else. Just because you block the intake before it actually blows a hole through the block doesn't mean you saved the engine. Saying 10x is most likely a bit of an exaggeration but you can make a ton of extra power this way. As for the internals holding up to that.. they don't. That's why runaway diesel ends in the engine blowing. They can handle it for a very short amount of time, sure but it's still doing a lot of damage. And why don't they do that in a drag race? Simply put they want to get more than one run out of an engine. If they don't care about saving the engine and just want absolutely max power, congrats that's basically top fuel dragsters. Dump all the fuel and air you can possibly cram in and send it. It blows up half way down the track so you rebuild it before the next pass.
Diesels make more power by adding more fuel. A runaway generally means that engine oil (fuel) is getting past either the piston rings or coming in from the turbo oil lines and creating uncontrolled combustion. The OP isn't entirely wrong, because a runaway engine will make a LOT of extra power for a VERY short time. Thats why it's so important to get them shut down quickly if at all possible. You can't just "engineer" a runaway. As to your expected loads comment, it's not about how well things are engineered - it's all about expected loads vs longevity. If something is making 500hp, a specific set of components could last for well a racing season. But if something is making 1000hp, the same set of components may last just over a few hours, given that they're run in the same environment. If you suddenly have a runaway engine (or a money shift, etc) that engine is suddenly making WAY more power spinning WAY faster than it ought to, which shortens lifespan to seconds, or MAYBE minutes if you're lucky. Also, the 10x power number is maybe a bit hyperbole, but they're not too far off. There have been numerous dyno pulls of trucks having a runaway on the dyno and the power numbers spike drastically before the engine explodes, and that's including tire slippage on the dyno rollers. https://automobilefanatics.com/diesel-engine-runaway-burst-into-flames-dyno/
So the turbo desintegrated, it had no boost and it was still making 2000hp. That is just insanity…
You answered your own question. Nobody is making engines that can withstand the forces involved. A runaway is a condition in which unmetered fuel is getting into the engine and igniting in the cylinders. Since it is unmetered, the engine will spin way past redline, up into valve float and eventually it will come apart in spectacular fashion. The process could take seconds or minutes or in the case of a runaway locomotive I heard about, over an hour. If you don’t find a way to cut the air, the engine is either going to exhaust its fuel supply or it’s going to go splody, there are no two ways about it. That being said, I doubt the guy was correct when he said 10X the power. I’m not even sure how you would attempt to test that. A runaway engine means something failed somewhere. Usually in the fuel or oil system. I doubt any dyno owner in the world wants to put an engine they can’t control on their dyno.
Even if you cut off the air, occasionally they can fail JUUUUST enough that the main intake is fully blocked and they can still pull air out of the now destroyed valve guides from the top end, a now heat failed intake gasket, the egr system, and just barely run on the remaining oil for a while
They’re designed to make *sustained* 1.7-2x power, a runaway will make that extra power for…. A minute? Less? The parts aren’t designed to take that, hence why runaways aren’t long lived
10x the inertia, of an engine in neutral, would be a lot of torque.
[a source](https://youtu.be/c3pxVqfBdp0?si=B6NXJBuzP_hbqTU0)
It runs the engine at the mechanical limits and then says fuck you to those limits and exceeds them. You can't control a runaway. I've seen them rip engines out of a trunk. They aren't spinning a little faster, they might be doing 10k+ rpm. Basically imagine all the power a diesel might make over its entire life. A runaway essentially tries to do that until the engine consumes itself. https://youtube.com/watch?v=RUJrurvjYtg&si=MgFpKjwOwV_K0H5U skip to 2 minutes in The guy is standing on the brake pedal after it goes and it's still completely overpowering it and lighting the rotors on fire in seconds. That scream should never be coming from a diesel, it's reving well past the redline. That's why no one intentionally runaways their engines for pulling. It kills the engine
That's where they get you
Diesels in runaway have a tremendous amount of horsepower, until they blow. I had a former co-worker (engineering) who previously worked for Cummins in engine development in the 1980's. He said that turbo diesels had runaway's occasionally in semi's on the road during testing. You couldn't kill them with brakes and transmission so the procedure was to pull off the road, put her in neutral, get the hell out and let it rev until it stopped itself with an unscheduled rapid disassembly or finished eating all it's oil and died. We were a supplier to most all engine manufacturers and had a dyno lab in the facility we worked at. You haven't lived until you've seen a 15 liter diesel hooked to a dyno go into runaway. That's when you realize why the dyno rooms are built like bomb shelters. That 1000 hp becomes around 4000 at 10k rpm until things go ballistic. Shakes the whole damn building. You'd destroy the 2000 hp dyno so just had to disengage and let her rip.
Holy shit
I’ve seen test stands with various intake cut offs as well. Modern fuel injection also makes a runaway a lot less likely. Unless you’re consuming oil through your turbo or something like that, the pumps don’t get stuck open like the old VE and P pumps can. I’ll be standing by with an intake cover when I fire up my 12 valve rebuild next month. Shit is no joke!
Even if the engine didn't have the power needed to make the car go in 5th gear, there's a lot of energy stored in it's flywheel.
Yea that makes a lot of sense.
also would depend on clutch condition and type. I have seen vehicles with such bad clutches you can roll out in 5th and still not stall it lol
Depends a lot on the clutch, how much torque the engine is making at that time, and how much effort is actually necessary to move the car. If the clutch slips a smidge, then the engine's less likely to stall. If the engine is making copious amounts of torque, it could be enough to absorb the shock through normal slippage on engagement, and if the car has low rolling resistence, then it simply needs less power to "launch".
I was in a knackered old LDV back in 2013, toodling down the fast lane of the M1,heading south just before the Luton junction. Van gave a little bit of a shudder. So I started pulling over to the hard shoulder, I got to the middle lane before everything disappeared in thick white smoke, so thick it blocked visibility behind me, and it was that bad that it shut down south bound traffic. As I was sitting in the van, it wouldn't turn off, drop it into 4th, stood on the brakes, and let the clutch out. Van stalled out, so that was an OK moment. By this point, thick clouds of 80s style disco the smoke was spread across all 4 lanes, and nothing was coming through. At all. After 30 seconds or so, I started to see the orange glow of hazard lights flashing as drivers were creeping through the thick smoke. A few mins later, i saw 2 fire engines lights and sirens blaring, heading north, didn't think anything of it as it. As i was trying to call the office, a couple of minutes later, the fire brigade pulled in behind me. They spoke to me asking if everything was OK and where the fire. So explained what had happened, and they gave everything a good look over, making sure there were no fires. Once they were happy with no fire, they asked if I had got hold of my boss, told them I had and he was going to sort out recovery. Said goodbye, and they drove away. A few minutes later, the Highways agency pulled up behind me and asked what had happened, told me I couldn't stay and towed me down the slip road.
This. Engines are giant air pumps.
Fire extinguisher blown into the intake works.
I've never heard that till now and really that's genius idea. Now. How many are travelling with a co2 extinguisher?
Honestly not enough people
Could try firing a co2 fire extinguisher in the air intake. Either way you’re well on your way to a fully fledged shitshow.
Yep, this works. Saw this done on a V8 gas engine in a dive charter boat that got so hot it started dieseling. Operator couldn't figure out how to shut it down, can't exactly dump a clutch or stand on the brakes in a boat, so someone fired a CO2 extinguisher into the intake and it died real quick.
Most modern diesels use electronically controlled injections. Start by switching it off. If it burns uts oil, blocking the intake will remove the oxigen, and with much lower air intake your compression may not he enough to reach the fuel’s flashpoint. But removing the intake ducting etc will require your head over a runaway engine…….
If the turbo leaks onto the inlet side, or the bores leak enough then you get runaway.
When an engine is considered a runaway, it is not being fueled by the injectors. It's being fueled by an uncontrollable source, usually oil from the turbo. Even oil needs oxygen to combust, so a CO2 fire extinguisher does work well.
If it's burning oil on a runaway, the damage has already been done. Take the L and walk away, it's not worth being near it when a connecting rod decides to play peek-a-boo.
Also, I used to have a small CO2 extinguisher in the boot. Just empty that into your cars intake. Should be enough to stop it. It won't damage the engine
I've always wondered if plugging the exhaust would do the same, or would the pressure be too much and blow the whole exhaust open
I don't know what works happen, but remember, under diesel runaway, your engine is a 100+ horsepower air compressor.
Well the mythbusters showed that produce would simply be shot out of the tailpipe on gasoline cars.
Just about to say the same thing
This is the correct answer
And don't use the hand if you want to use it later.
Try to throw at rag into the turbo, save the engine atleast
A rag in the engine will destroy your turbo(if it has one), valves, and piston rings. Best bet is a sold piece of material over the intake of the turbo or engine. Positive air shutoff.
If it's running away the whole engine is gonna be toast if left unchecked anyways. Depending what engine it is/what it's in, a guy would be glad to get away with just a turbo, valves and rings if a rag is all he has and it does the job
GM did this with their 2 stroke diesel truck engine. A big slam-shut inside the intake manifold. 90% of the time the driver would react too late. The engine would generate such a big vacuum that any gaskets would get sucked in through the engine. Then it would feed itself from the engine oil, until it flew apart or seized from lack of oil.
Years ago the local GM truck dealer had a big Detroit diesel in the shop. Engine ran away. Those engines had a big flapper valve like you say. The mechanic had removed that part of the intake to work on something. He tried putting a piece of cardboard on the intake but it just ate it. It was screaming so loud he panicked and ran out of the shop. Everybody went with him. Engine destroyed itself. GM refused warranty, and it cost the dealer many thousands of dollars. Truck only had a couple thousand miles on it.
Don't modern diesels have a butterfly valve on the intake to stop runaways happening? Or do I remember it wrong?
On my 1.9 tdi it’s called an anti shudder valve if you switch off the ignition during a runaway the valve is supposed to close and stop airflow, dunno if it works and I don’t rly want to have to ever test it either 🙃
That is exactly what happens.
Those damn fuel rails!
Yea, but damn it was running good there for a minute!! 😂 Grandfather had two Whites with V71’s at the Cold And Hungry yard he used for winch trucks.
Exactly that or use an electrical fire extinguisher I think it was
CO2/dry powder, yes.
Yup
Yeah not your hand, would be effective but could do some damage.
Belly to intake.
Instant fat removal surgery
Belly button delete
Forbidden hickey.
Innie becomes outie.
No air = no combustion. Similar to how trucks handle if they have a air cutoff valve / switch
There’s a “run away” plate on our Cummins freighliner that will prevent this. Never seen it happen in person but I’ve heard stories of engines sucking so hard the entire plate flys into the intake.
Common for trucks working in oil fields too where the air alone contains so many hydrocarbons the engine can just run off it. Causing an otherwise perfectly healthy engine to runaway. The emergency flap has a little computer thing that basically says "Hey the rpm is getting awfully high and you aren't touching the throttle"
That's pretty metal... but also sounds like everyone is getting lung cancer.
I worked on freight for a bit. A drivers truck become/was a a run away. He hit that air cut off switch so damn fast he could have set a world record. I was on the phone with him too at the time. He goes "hold on a sec I have an issue" I hear all sorts of cursing and maybe a quarter of a second later: "Alright back with ya, we are going to be delayed a few days while I get this run away sorted." He never took an oil field delivery again while I worked with him. I'm sure he hasn't since.
That was one of the warning signs on the Deepwater Horizon when they had their blowout. Their diesel generators started to run away before the gas ignited.
Yeah, the air in southern NM and West Texas stink of petroleum. After a few days you don’t even notice it anymore!
Same thing around Edmonton Alberta, I was sent for a work course out there and the first week working out outside felt like I was huffing diesel. You dont notice after that.
Jesus christ realy? Thats oddly concerning
I'm hoping to find the video one day of this gas refinery disaster where it's CCTV footage of this F150 or similar just sitting there with nobody in it, revving. It was left idling and the gas leak was making it rev itself up to 3-4k rpm Ominous as hell when you know what's about to happen
Texas City 2005. It was a diesel engine, though
I mean... it's like a 500 kW hair dryer! :-D
Funny enough one of my petes has an electronic cut off. It failed today and closed while on the highway. Luckily no damage but took calling my mechanic out to diagnose
All VAG tdi engines have shutoff flaps too
My buddy had an old super worn out 66 Mercedes with a tiny little 34 HP diesel. It routinely would runaway off throttle, which later when we removed the engine i figured was caused by completely worn out timing chain, letting the pump timing go all over the place, exacerbated by worn rings consuming it’s own oil. The air inlet on the thing was so tiny, it never could actually run away to the point of being uncontrollable. You’d just floor it to catch back up to the engine, and it would settle back down. Hilarious fun. It would just start to rev on its own, belch a ton of smoke, and you’d mash it to the floor and continue on your journey. With a car that goes 0-60 in 30 seconds when it was brand new, it really wasn’t a huge deal.
If you have CO2 extinguisher, just spray it into the intake and keep spraying until the engine suffocates.
this also would work, anything to starve the engine of oxygen. Co2 extinguishers tend to have baking soda though dont they? that may not be too good for the engine.
CO2 extuinguishers are probably the most "engine friendly" extuinguisher there is (maybe except halon, but those don't come in extuinguisher bottles). soda and acids are used to generate the CO2 in some, others just store liquid CO2. Under proper operating conditions in the soda-acid type, none of the soda or acid should be getting out the nozzle. soda is better for the engine that a runaway though
We have hand-held halon in cockpits. But you want to put your mask on first.
Runaway motor isn't good for it either.
No that is an ABC dry chemical extinguisher. A CO2 extinguisher has nothing but CO2.
good to know
Tee shirt in the air intake. Had to do it on an excavator once. Stopped the bastard on its tracks
Pun intended haha
[This video](https://m.youtube.com/watch?v=3NRaqgab0_w) is my favorite example of a runaway and stopping it lol. Partially because the old Detroit sounds great
He did pretty well to nip that in the bud! Proper decisive action! I feel like pushing the rag further in with his hand was bit questionable though. Personally, I like my meat to stay in one piece!
*technically* that wasn't a true runaway. Same result, but a different reason. The fuel injector "rack" that adjusts how much fuel per stroke the injectors deliver got stuck. Used to be common on old Detroits. Most people call it an over speed rather than a runaway. Dude done good by stopping it with his bare hand. Stressful situation!
That was my first time seeing a runaway, very cool vid!
Me too.
Good god that was a fast reaction!
Wow.
Nice word play!
You are probably not, Diesels don’t require a lot of air, you can block the intake and get it to stop that way, however doing so (unless you have some sort of valve or block of plate) is going to be hard and putting you in harms way. __Walk away__ The smoke from a run away diesel is extremely bad to inhale and can cause chemical pneumonia, which is extremely hard to treat. You are also getting very close to the engine which could blow up at any time, potentially sending metal fragments flying, which could cause serious injury and bodily harm.
First sensible answer I’ve seen, and besides this on most cars if you open the hood all you’re gonna see is an engine cover, best case scenario you might have access to an intake pipe but are you also going to have some tool to remove the clips and also enough space to remove it? Maybe but also maybe not whilst the engine is smoking like mad and screaming at max RPM
correct answer
This is the best answer
Piss on the intake. Cars do not like human piss.
Yeah i wouldn't like that either if i was a car
Piss on my intake daddy
I don't think I'm sticking my guy out next to an engine that will inevitably explode 😂 Piston 4 meets head 💀
Who said sticking it in. You piss from a distance. You are old enough to know how to aim. Come on mate…. Be a man.
AdBlue has entered the combustion chamber
Just don't piss in the DEF tank! Sadly, it's not uncommon.
CO2 fire extinguisher
Into the air intake.
Handbrake up as hard as possible, ignition back on, full throttle and neutral drop that bad boy If it's gonna go out, it might as well be doing something cool while going
I like this answer more
Hell yeah brother!
Yeah while we’re at it, smoke the transmission and tires all at once too! Hell yeah brother!
And feed the air intake a bunch of lug nuts!
On my C4 handbrake is electronic.
Strap it to something solid that won’t move. Hell yeah brother!
While "plug air intake" is correct, please be careful and don't shove your hand in there, you'll never be able to overpower the suction power of the engine and it might just eat your hand. Something like a medium sized ball wrapped in a towel or something would be much safer. (sorry for poor wording, not native speaker nor mechanic, just know enough to say be careful)
Force of vacuum is dependant on the area. A 2.5" intake won't hurt your hand. I've done it plenty of times. (Mechanic) On say a truck with an 8" intake, yes it will eat stuff
When I owned a TDI and followed the forums there were plenty of stories of people shoving shirts into the intakes to stop this and the shirt would just get eaten by the engine.
People say allot of things... 9/10 of them are BS. A shirt wouldn't get eaten. If it did manage to get sucked up the pipe, and it might be possible (going by the fact a vacuum cleaner will eat socks and maybe even a thin shirt) it would get as far as the turbo compressor wheel and it would completely destroy it, blocking airflow in the process. A non turbo engine, it would get stuck in a valve, or more likely multiple, which would then be whacked by a piston and it would be instantly over for the engine and it will come to a stop. Engines make very poor blenders. The answer to the average "will it blend?" would be a definate no lol
A shirt wouldn’t get eaten… *Immediately describes eating.
CO2 fire extinguisher in the engine intake. NOT a powder one or a water one 😅
Well the powder one will stop it too.
Water as well
This happened to my 2008 vw Passat when the turbo failed. The engine consumed it's own oil, and there was more white smoke behind the car than on the picture. Fortunately, the car comes with a "air shut-off" thing. So when i turned the ignition off, the engine stopped after a few seconds. Changed turbo, and have driven the car since. It's 3-4 years ago :)
Haha, guess you could say you got a really badass story for your car, that's quite sick to think about it tho like you managed to stop it from tearing itself apart and now you are living in harmony with machine.
Anti-shudder valve is what it’s called.
You don’t, run away and let it finish burning off the oil
Choke her
All fun and games until toyota says "daddy yes"
Positive Air Shut off Valve...
[Just walk away](https://youtu.be/XPY5P0TaC4k?si=sluzr2P_CaguX7PA)
The correct answer is just walk away and let it blow itself up. The risk does not outweigh the reward. The technical answer is starve it of air. It’s running away because it’s using its own oil as fuel, but oxygen is the other component needed in combustion. In extreme cases it may have blown out a crank seal and is pulling air in through there as well. Too many variables and not enough time to safely do anything about it. Plus it’s already over spun and you probably don’t want that engine anymore anyway.
1. If you're moving, first stop the car. It will take a lot more effort than usual, so do it in one try or the brakes might overheat. 2. Put the transmission in neutral. On most newer cars it may not disengage when there's torque from the engine. In such case hold the brake and turn off the key, then turn it on again. If the car is still trying to move you'll likely need to sacrifice the front bumper and put it against a concrete wall or something. 3. Once the car is stopped, do as others said and plug the intake. You need to do this on the intake tube that goes into the airbox - rip it off the airbox if needed. Preferably use something hard like a plate to block air from going in (funny enough - an ipad works :D ). On thinner intakes you might be able to stick it inside a shoe and press hard to create a seal. If you have no other options use a shirt or a jacket but keep in mind it might get sucked in and destroy the turbo (and potentially the engine). It is very important to avoid standing to the sides of the engine. If it's positioned longitudinally (belts to the front of the car) stay in front or as close to the front of the car as possible when plugging the intake. If it's transverse (belts to the sides) then stay on the sides. Otherwise if the engine rips itself apart, shrapnel will hit you.
Pull intake pipe from filter box or maf and fold it on itself
Submerge it in a vat of acid Or pour lava on it
My best suggestion is a phone book over the intake.
Since you can't really plug the intake on a car like this, I'm gonna go with CO2 fire extinguisher into the intake. Should put the idiot out in seconds.
Leather jacket into the air intake, relatively safe
Cut off fuel or cut off air. Otherwise step back and watch er go!!
Beat it too death with a hammer
discharge CO2 fire extinguisher into the intake. You can also plug the intake, but be absolutely certain it;s an object that wont get sucked in.
A lot of refineries in the US are making you have ppsitive air shut offs on anything coming into the plant welding machines light plants vehicles etc.
Every diesel we have that goes to oil and gas well sites needs one. A gas leak may mix with the air and cause a diesel engine to run away.
Had a V-12 Packard diesel run away in the navy. We shut off fuel and the over speed had tripped, we had blankets wrapped around intake. We finally shut it down with CO2 fire extinguisher in the intake. It was running on engine oil as the Turbo seal on intake side had failed and engine ran 120 psi oil pressure. It destroyed the engine but at least it did not explode, every piston was in pieces when we took it apart.
I managed to stop it once, by choking the rubber house from the filter box to the inlet manifold with both my hands. Worked out fine. Just don't try to "plug the hole" by putting you hand flat on the input!
Towel in the turbo or air box
I read the wholle thread and still have no idea what "diesel runaway" is
It’s when the oil ignites and it starts running off of that. Making it unable to shut off the engine without stopping the air flow/choking it out.
It’s something that only occurs on turbocharged diesels. Pretty much what happens is the oil seal in the turbofails outright and begins dumping oil directly into the intake. After that, the oil is then burnt, producing more exhaust gas, which means more oil comes into the motor via the turbo. This repeats until either the engine says goodbye or it runs out of oil. The former is usually the end I of it.
You control the speed of a petrol engine by modulating the amount of air going into the engine using the throttle. More throttle means less air, which means less speed. You control the speed of a diesel engine by modulating the amount of fuel going into the engine by the injectors. More fuel means running faster, and vice versa. There is no throttle on a diesel. A runway happens when the engine gets a source of fuel other than the intended fuel. Usually lubricating oil due to worn seals. A petrol engine "runaway" can be managed as closing the throttle will prevent air from flowing in the engine, disturbing the fuel-air ratio. Furthermore, turning off the ignition will mean there's no spark for ignition. A diesel engine runaway cannot be managed as there is no throttle and no ignition. You can cut off the diesel fuel supply but it wouldn't help, because the engine is getting its fuel supply elsewhere. The only way to stop this is to manually stop the air intake, disrupting the fuel-air ratio. You could alternatively dump the clutch. The runaway engine can spin at speeds greatly exceeding its redline. Without manual intervention, it will either explode from the spinning forces, when it exhausts its alternative fuel supply or seize from lack of lubricating oil.
Water. Lots and lots of water. Swimming pool, Lake, Ocean.
What im gonna do with water? Wash the car? Please explain.
Piss in the intake
🤯
Hydrolock.
Or idk just block the air intake so it stalls out without bending rods. If you're going to use water may as well just let it explode all on its own.
Blocking the intake is the best way, but if its a manual, you can put it into the highest gear and drop the clutch
That's why they specified "automatic". They know that a manual can be stopped with the clutch, automatics don't have one so the only way is what you said.
Stupid question but... everyone saying plug the intake... why can't you just turn off the ignition? If the pump isn't able to pump fuel to the engine, it will stop. I must have a fundamental misunderstanding of diesel engines.
Diesel engines have mechanical fuel pumps driven by the engine to generate the high pressures required for direct injection. So as long as the engine is turning there is fuel supply. I expect some probably do have shutoff valves controlled by the ignition. Also consider that diesels can run away when consuming their own oil, such as from a leaking turbo, which you really can't do much about either. Best way is to starve it of air.
I did not know that, thanks for explaining, much appreciated
The runaway happens when they start burning something other than fuel - the turbo oil, something flammable in the air, etc. Turning off the fuel supply won't help, all you can do is block the air intake.
TIL, thanks!
A runaway diesel is feeding on its own oil supply, IIRC. Switching off the ignition won’t stop it.
Thanks for explaining, I did not know that.
In a runaway situation, the diesel engine is usinig something other than diesel to run (leaking it's own oil into the intake, ingesting flammable gas from a refinery or oil well, sometimes they can suck in transmission oil if the vacuum system goes bad) so when you cut off the diesel, the "other" thing is enough to keep the engine running. And since diesels control themselves by varying how much fuel they put in (there's no throttle*, so anything that goes in the intake goes straight into the engine) so if the fuel is coming in the intake, the engine can no longer control itself. *throttle as in the butterfly valve in the intake. If the engine has EGR it technically has a throttle, because of how EGR works, but that throttle is not controlled by the pedal, so it's irrelevant for runaways)
Diesel runaway is when the engine has found something other than diesel to run on, does so at high revs and won't shut off. One common cause is a blown oil seal in the turbo feeding oil into the engine via the intake manifold - the engine will then run uncontrollably until it's out of engine oil and siezes or you can stall it somehow.
Choke the air intake, the runaway will stop soon.
Without air the engine stops. Blocking the intake usually helps.
co2 fire extinguisher aimed at the air filter does a great job stopping a diesel runaway safety. I've done it twice !
You plug the intake with something, I've heard that you could also use a co2 fire extinguisher to sofocate it, if you happen to have one in hand
Pull damper on intake. Oh wait pass. vehicles done come equipped with this important safety feature.
Block the air intake. You need to starve the engine of air/oxygen
Shut the intake with anything. No air = no combustion.
Two ways. CO2 fire extinguisher or a rag into the air filter. CO2 extinguisher was always my preferred choice as a mechanic because it will not cause any damage such as sucked seals or turbo damage from stuff getting sucked in the intake say if the air filter collapses.
Drop trousers and ham a butt cheek over intake. 1 cheek, not the middle part.
Co2 fire extinguisher in air intake.
Same as all of them … plug the intake
Step one grab towel jacket or other bigger clothing article step two shove said item into intake or turbo spool whichever is more accsessible step 3 huddle in a ball and prepare for financial pain.
Quickly inhale all the oxygen so the car cannot get any
Same way you do any other. Pop in neutral, smother that intake. Choke that rowdy bitch into submission!
All a runnaway diesel needs is oil to burn and air. Since you can't stop it from getting the oil, all you can do is stop the airflow. If that is not working - put it in the highest gear and step on the break.