Cars: smart keys, stupid passengers
August 6, 2012 8:05 AM Subscribe
What would happen if I tried to turn off a push button/smart key car while driving? I was in a car where it was on the gear instead of near the steering wheel, and I got curious when I realised I could easily turn the car off, or try to. I'm especially curious what would happen at high speed. (Not curious enough to try it, but curious enough to use up this week's question.)
You'll definitely lose power steering. If you have a powered brake booster, you'll probably lose that too after a few pumps, depending on how much charge is left in the capacitor.
Other than that, I don't predict it'll be much of an issue - it's certainly nowhere nearly as bad as shifting gears incorrectly. Your car will simply coast to a stop.
posted by wolfdreams01 at 8:20 AM on August 6, 2012
Other than that, I don't predict it'll be much of an issue - it's certainly nowhere nearly as bad as shifting gears incorrectly. Your car will simply coast to a stop.
posted by wolfdreams01 at 8:20 AM on August 6, 2012
it's certainly nowhere nearly as bad as shifting gears incorrectly
I've actually accidentally shifted into "park" before with an automatic transmission car (one of those ones where the shifter is over the steering wheel) - it was very similar to slamming on the breaks. With my Prius, pushing the ignition while in gear puts it into park first, so I think it would either be disengaged at speed or would be similar to putting a standard car into park at speed.
posted by muddgirl at 8:34 AM on August 6, 2012
I've actually accidentally shifted into "park" before with an automatic transmission car (one of those ones where the shifter is over the steering wheel) - it was very similar to slamming on the breaks. With my Prius, pushing the ignition while in gear puts it into park first, so I think it would either be disengaged at speed or would be similar to putting a standard car into park at speed.
posted by muddgirl at 8:34 AM on August 6, 2012
I have a friend who is into getting extreme gas mileage. He will cut off his engine on a highway while going downhill drafting behind an 18-wheeler. He says the only issue is he loses power steering and has to brake harder (if necessary). He turns the engine back on at speed too. He is in neutral while doing this.
I have never been in the car during this trick. No intention of being in it either as the braking and steering issues concern me.
posted by JohnnyGunn at 9:18 AM on August 6, 2012
I have never been in the car during this trick. No intention of being in it either as the braking and steering issues concern me.
posted by JohnnyGunn at 9:18 AM on August 6, 2012
I rented a Volvo S60 last week and was curious enough to try it at about 120km/h on the autopista - nothing happened. I assume the computer ignition system on the card is intelligent enough to not cut out the engine while the car is in motion. I also assume that there will have been some override, such as described by punchtothehead in the case of some emergency requirement to shut the engine off.
The engine would automatically shut off when the car was stationary and I applied the handbrake and put the car into neutral. Popping the car back into gear would start the engine automatically again.
posted by benzo8 at 9:54 AM on August 6, 2012
The engine would automatically shut off when the car was stationary and I applied the handbrake and put the car into neutral. Popping the car back into gear would start the engine automatically again.
posted by benzo8 at 9:54 AM on August 6, 2012
I think the answer is "it depends." There is some push for legislation to make all cars sold with push button ignition behave in the same manner (as an emergency kill switch). Data point: my 2007 BMW, the owners manual says "do not operate the push-button ignition switch while driving the vehicle except in an emergency."
posted by fixedgear at 10:12 AM on August 6, 2012
posted by fixedgear at 10:12 AM on August 6, 2012
This is consistent with the general safety advice that proscribes shutting off your car while driving--- some people think this is what to do when you've got a stuck accelerator, but it's a bad idea because of all the other things that shut off, i.e. power steering as identified above, brake anti-lock system, the possibility of the steering-wheel lock engaging, etc.
The proper move is to shift into neutral, come to a stop, and then kill the engine.
Power switches based on remote systems aren't going to be basic mechanisms in today's cars-- not with all those lawyers and driving fools out there-- any kind of keyless ignition switch is going to have to work its way through a car's computerized logic tree to prevent people from succeeding when they accidentally or deliberately or drunkenly attempt foolish stuff like shutting off a speeding car. I'm sure the actual logic varies from automaker to automaker, if not even car-model to car-model.
posted by Sunburnt at 1:38 PM on August 6, 2012
The proper move is to shift into neutral, come to a stop, and then kill the engine.
Power switches based on remote systems aren't going to be basic mechanisms in today's cars-- not with all those lawyers and driving fools out there-- any kind of keyless ignition switch is going to have to work its way through a car's computerized logic tree to prevent people from succeeding when they accidentally or deliberately or drunkenly attempt foolish stuff like shutting off a speeding car. I'm sure the actual logic varies from automaker to automaker, if not even car-model to car-model.
posted by Sunburnt at 1:38 PM on August 6, 2012
I tried this a little while ago in my 2006 Acura. It doesn't have a pushbutton but instead has a switch on the steering column where the key would normally be that functions much like like a pushbutton when the smart key transmitter is nearby. After checking the owners manual, which didn't address this issue anywhere I could easily find, I decided to turn the car off under 3 conditions. In gear and stopped turning off the engine killed power to the instruments, power steering went away, and power brakes went away after about 3 pumps. The engine would not restart until I shifted into park or neutral and moved the switch to the start position. While driving slowly the behavior was the same except the power steering warning light came on. It stayed on for about a minute and went off without further intervention. Finally, when I was on a straight, empty section of highway, I shut off the switch at 50-60 mph. The power steering did not seem to be affected but that may be because of my speed and/or the fact that I didn't test it very hard. The brakes seemed to work normally as well, but once again I did not test them very thoroughly. The engine did start back up as soon as I returned the switch to the run position, and this time both the power steering and adaptive braking warning lights came on. Once again the warning lights went off on their own after about a minute.
posted by TedW at 5:01 PM on August 6, 2012
posted by TedW at 5:01 PM on August 6, 2012
A lot of new cars have electric power steering so it will still work without engine as it will draw electricity from battery instead of needing to have a hydraulic pump, like on older/cheaper vehicles, provide the power steering which is spun by the belt from the engine. They switch to electric for fuel economy.
Brakes are hydraulic but power assist comes from the vacuum engine makes. It does have a reserve so even with engine shut off you can fully press the pedal about 3 times, then it will get very stiff but still work. That's why I set my seat a bit closer so I can 1. fully depressed it easily in an emergency, 2. be able to brake when engine dies for any reason. ALso with 415 HP and torque my car pushes me so far into the seat I lose grip of the steering wheel.
None of the automatic cars will let you start the engine with transmission in gear, unless something is broken. Only in neutral or park.
Hyper-milling is stupid. There will be time when they will need the power accessories and they will die/get hurt. You can't predict anything on a public road.
Also more and more modern cars get automatic start and stop of the engine so it is shutdown when you are stopped and starts right up when you need to go to save fuel. I wonder how long the starter will last but it should be fine during warranty period.
posted by AdamG8GXP at 10:30 AM on August 30, 2012
Brakes are hydraulic but power assist comes from the vacuum engine makes. It does have a reserve so even with engine shut off you can fully press the pedal about 3 times, then it will get very stiff but still work. That's why I set my seat a bit closer so I can 1. fully depressed it easily in an emergency, 2. be able to brake when engine dies for any reason. ALso with 415 HP and torque my car pushes me so far into the seat I lose grip of the steering wheel.
None of the automatic cars will let you start the engine with transmission in gear, unless something is broken. Only in neutral or park.
Hyper-milling is stupid. There will be time when they will need the power accessories and they will die/get hurt. You can't predict anything on a public road.
Also more and more modern cars get automatic start and stop of the engine so it is shutdown when you are stopped and starts right up when you need to go to save fuel. I wonder how long the starter will last but it should be fine during warranty period.
posted by AdamG8GXP at 10:30 AM on August 30, 2012
This thread is closed to new comments.
Do not operate the push-button ignition switch while driving the vehicle except in
an emergency. (The engine will stop when the ignition switch is pushed 3 consecutive times in quick succession or the ignition switch is pushed and held for more than 2 seconds.)
posted by punchtothehead at 8:13 AM on August 6, 2012