How do I stop a car stuck going full speed ahead?

[38034580]

Suppose this happened: The spring got damaged and now the car is stuck at full speed ahead. What to do? Or what do I have to install to cut air to the engine in a situation like this?

[Fasauceome]

If you can shift to neutral, do it. If you lost your brakes, and power steering, you may have to pull the keys and engage the emergency brake. 

 

But pretty much always shift into neutral if you have a runaway engine.

[Guest]

Install a 12v battery kill-switch inside the car, 90% of serious race cars have them, for just such a reason.  *click* engine shuts off, if done properly.

[dalekphalm]

24 minutes ago, 38034580 said:

Suppose this happened: The spring got damaged and now the car is stuck at full speed ahead. What to do? Or what do I have to install to cut air to the engine in a situation like this?

Depends on why - if the throttle is stuck, just pop the car into neutral (and if possible then shut the engine off).

 

If the throttle is stuck, and a series of catastrophic failures happen that mean your transmission is stuck in drive, and your ignition system is also stuck, then your best bet is probably a soft crash. Drive into a field with tall grass, slightly sloping hill, etc - essentially you need to overcome the power of the engine/traction and make the car "stuck" onto something. But if you're in this situation, you're probably fucked. Though let's be clear, for all of these failures to happen, that's very unlikely.

[vf1000ride]

I've had this happen to me 20 some years ago, something to remember that when you turn off the key you may also be locking your steering wheel in position as well, you won't be able to turn it anymore.  Something to check on your personal vehicle while your still parked.  Putting the shifter in neutral is first step then worry about turning it off and slowing down. Most cars with vacuum assisted brakes are also going to lose the power assist on your brakes when either the engine is turned off or stuck wide open.  

[Guest]

Depending on the car.. a lot of manufacturer's put the ECU within reach of passengers, you could in theory unplug it to kill the engine.  There isn't really a good or best thing to do in that sort of crazy situation.  Only if the vehicle is setup properly with fail-safes would there be anything you could do 'safely'.

[38034580]

36 minutes ago, James Evens said:

You still have the clutch and transmission?

I have an automatic.

[Middcore]

OP, if you are posting this from inside a speeding car, I must commend you on your icy calm. 

[Monkey Dust]

Happened to me shortly after learning to drive. Fortunately the car didn't have a lot of power, so could slow it down pretty well with the brakes and turn off the engine and coast to a halt. To get going again, put it in first, keep clutch depressed, start the engine and release the clutch. Fortunately I wasn't far from home when it happened. 

 

It shouldn't be possible for the throttle to stick open with drive by wire throttle, which is just about any car built in the last 15-20 years. If it is stuck on a modern car, you should probably check the mat... From the auto point of view I guess if it's old enough to have a cable throttle, it's old enough to have a physical connection from shifter to box, so I don't see why you couldn't shift into neutral?

 

     

[Beerzerker]

 I have to say putting it in neutral isn't a great idea either, chances are if the engine is running away, it will blow and then you lose power brakes, power steering, possibly oil coming out and all over the windshield......But if you have no choice then do as you must of course.

BTW I've had it happen before. 

It took me a few tries (71 Chevelle SS) and it went to lock each time but finally got it off without locking the steering and stopped it safely.
There is a decent to good chance, based on the actual keylock mechanism it has as it was in my case you could go all the way back to "Lock" but if you don't panic, you can get it shut off without locking the steering wheel.
Most vehicles today don't have the same (Clunky) lock setup, it's much easier to get it off without locking the wheel.

If you do lock the wheel, just turn it back "On" and try again - And bear in mind this could blow out a muffler in the process (Sounds like a shotgun going off in the car - And I should know  ) but better than losing all the assist and the engine....
But I will say if you gotta blow it, then neutral it is since even that is better than certain collision/wreck.

[Ravendarat]

1 hour ago, si1enze said:

Depending on the car.. a lot of manufacturer's put the ECU within reach of passengers, you could in theory unplug it to kill the engine.  There isn't really a good or best thing to do in that sort of crazy situation.  Only if the vehicle is setup properly with fail-safes would there be anything you could do 'safely'.

As someone that works on cars everyday including often working on the ECU I can confidently say this is NOT the case. It would be extremely tough to unplug almost any ecu while also keeping control of a speeding car. The right answer here is to turn the key back to accessory, this will turn off the motor while not locking the steering wheel, also you cant turn the ignition completely off while the car is still in gear, That will turn off the motor and then you can simply brake with the foot brake or ebrake and stop safely. Now if the car is push to start the answer changes somewhat.

[Guest]

4 minutes ago, Ravendarat said:

It would be extremely tough to unplug almost any ecu while also keeping control of a speeding car.

Well yeah, hypothetical situation and all.  What do you think would happen if you unplugged the ECU on a running EFI car ?  ECU tells the coil when to fire, no?

[Ravendarat]

1 hour ago, si1enze said:

Well yeah, hypothetical situation and all.  What do you think would happen if you unplugged the ECU on a running EFI car ?  ECU tells the coil when to fire, no?

Oh it would definitely kill the motor and a lot of other systems, its just unlikely to be able to be done on many vehicles

[Zodiark1593]

22 hours ago, James Evens said:

Bad idea. Pulling the keys means the steering lock will engage.

Bold of you to assume my econobox has a steering lock. (Hint: it doesn’t) 

 

I drive manual, so I’d probably press clutch, go to neutral, and cut the engine to keep it away from the limiter, if I’m on the freeway. At speed, steering is easier until you slow, though you’ll lose power brakes fairly quickly. 
 

On a downhill, I’d cut the engine while still in gear, which will provide engine braking to help with slowing down without power brakes. 

[airborne spoon]

On 5/20/2021 at 1:02 PM, si1enze said:

Install a 12v battery kill-switch inside the car, 90% of serious race cars have them, for just such a reason.  *click* engine shuts off, if done properly.

Nope, installing a 12v kill switch will only cut off your battery but the car is running off the alternator power while turned on. When i was younger and couldn't afford a new battery i removed the old battery and would always park on a hill and bump-start my car and it would run fine because the alternator was what powered the thing. Did the same thing when my starter went out like a year later till i could afford one. But i digress to have an effective kill switch you would need to kill the spark, this was easy with cars that had a distributor but in newer cars with the coil on plug crap you have to trace back the line for the crank position sensor and install a switch into that and usually if the car doesn't get a signal from the CPS it will not spark thus killing a runaway engine. For a diesel engine its more difficult because they don't have spark and a lot have mechanical fuel pumps, in that case the best option is to block the intake remotely as blocking the exhaust enough to kill the engine could create an explosive situation. So you could install a door in the intake that you could control via manual cable or electronic switch.

But the easiest option for any car is to put the car in neutral and get it to stop then pop the hood and block the intake with your hand or a rag or shirt till it dies. Also brakes are required law to be separate system and they have to be manually controlled. So like a tesla that has 1 pedal driving you hardly ever use the brake but if you push the brake it doesn't do some electronic braking it is still the same normal hydraulic brake that every car uses and no matter the situation short of the brake line being cut the brake will function if depressed.

Now if your brakes are shot and the ebrake is shot too then you could do a few things all of which are not ideal and will result in expensive damages. If there are other cars on the road you can try and rear end the fastest one thus resulting in your initial impact being as minimal as possible and they will then use their brakes to slow that crash train down to a stop. Or you could use the guardrails to slow the car enough to ram the car into a strong light pole or a tree. but again not ideal and expensive and there will be injuries very likely.

 

[Guest]

If done properly meant it would disconnect the alternator, but yeah.

[N1tro199]

Aim for the closest tree

[spartaman64]

1 hour ago, N1tro199 said:

Aim for the closest tree

collisions with trees are actually some of the deadliest because the tree doesnt move so you take all the force. its better to collide with a parked car or something else that gives way though the downside to that is you potentially have to pay for damages

[Ralphred]

On 5/20/2021 at 9:11 PM, James Evens said:

Bad idea. Pulling the keys means the steering lock will engage.

Don't pull the keys, just turn the engine off.

Leave it in gear, this will keep the engine pulling a vacuum so the the servo assisted breaks will still work.

It will also keep the power steering pump (9/10 times) working so you can still steer.

 

Reason for not doing "x":

Putting in neutral (with engine off): Pulls no vacuum, might run out of reservoir to assist breaking.

Putting in neutral (with engine on): Rev limiters sound like shyte, most likely to annoy you into crashing the car just to "make it shut up".

Overcome the engine with brakes: Whilst this might work initially, you are likely to overheat things and cause a spongy brake pedal/poor response.

 

The main thing is to not panic, and any time I have had a stuck throttle, just slapping the pedal down hard and quickly freed it enough to continue the journey until it was safe to investigate.

 

As far as "adding" a cut of switch, it really depends on vehicle age. Unless you have a mechanical fuel pump* on a an old diesel engine, cutting the ignition-system/injector/fuel-pump power will bring things to a halt.

 

*In this case your "emergency cut off" will be a literal tap on the fuel line.

[Donut417]

On 5/20/2021 at 4:02 PM, si1enze said:

nstall a 12v battery kill-switch inside the car, 90% of serious race cars have them, for just such a reason.  *click* engine shuts off, if done properly.

Thats suppose to go on the power leading to the fuel pump. If the engine has no fuel it wont run. ChrisFix has a video on how to do it. 

[Beerzerker]

Another method is in how a runaway diesel is shut down, just block/close off the air intake.
No air, it can't run.

It's possible to create a solenoid actuated cover/flap that cuts off air going in for that purpose.

[wONKEyeYEs]

On 5/20/2021 at 4:23 PM, 38034580 said:

I have an automatic.

Then you have a transmission which can be put in neutral.

[MadAnt250]

On 5/20/2021 at 3:36 PM, 38034580 said:

Suppose this happened:

This has happened, there are videos out that inform you what to do in this situation.

[cardboardtruck1000]

power slide into a tree be very carful also call 911

[BlueChinchillaEatingDorito]

Potentially dangerous idea... tiny explosive charges on all wheel nuts.