The Dangers – and Causes – of Unintentional Idling

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If you don’t think your engine’s still running, you might forget to turn it off. Well, you might forget to push the ignition button off – because the engine isn’t running right now. It seems to be off.

So you think it is, don’t push Off  . . . and leave the car.

Which starts running again a few minutes after you left.

This can – and is – happening because of Automated StartStop (ASS) the new “feature” many new cars come standard with as a fuel-saving measure. Whenever the car stops, so does the engine – the idea being that a non-running engine doesn’t burn any gas or emit any gas. The gains – and reductions – are almost immeasurably small per car but necessary from the standpoint of regulatory compliance – the fuel economy and emissions fatwas that are becoming otherwise impossible to comply with – without switching over to electric cars, which is another story.

So ASS automatically turns the engine off whenever the car isn’t moving, as at a red light or when traffic stops moving. When the driver takes his foot off the brake and depresses the gas pedal, the engine automatically restarts itself and the car resumes moving.

That’s the theory. Here’s the problem:

ASS can’t tell the difference between stopping for a red light or because traffic has temporarily stopped – and stopping because you’re parking. If you forget to push the ignition button off – which is easy to do when the engine has already turned itself off – the engine will restart after awhile, even if the car isn’t moving (and you’re no longer in it) because otherwise the battery runs down – because electrically powered accessories will still be powered if the ignition is still on.

If the engine kicks itself back to life when the car is outside, it’s no big deal. Gas will be wasted – and emitted – as the engine idles.

But if it idles for hours in your garage, it could be a very big deal – if the gasses emitted find their way into your house.

Several people have already been killed by the gasses emitted from cars left unintentionally idling – a modern problem that first arose when keyless/push-button ignition system came online in mass-marketed cars in the early 2000s.

People sometimes forget to push the Off button – or thought they did push it – and leave the car with its ignition still on.

This is easy enough to do when you’re in a hurry, or preoccupied by other things. Modern car engines are very quiet, even when they are running.

And pushing a button isn’t the same as turning – and removing – a key.

A physical key in a physical lock has to be physically turned to the Off position before the key can be removed from the lock. Most people who are parking their car will not leave the key in the ignition. The act of removing the key automatically entails the act of turning off the ignition and thereby, the engine.

This has been a failsafe against unintentional idling for the past 100 years – until about ten years ago – when keyless/pushbutton ignition systems became popular.

People in a hurry or not paying attention no longer had to shut off the engine in order to remove a physical key. It was now possible for them to assume they’d shut off the engine – because they thought they’d pushed the Off button . . .  and walk away from a still-running car.

If you’ve had a chance to drive a car with pushbutton ignition, you already know all about this. Some systems require an extended push to register the driver’s intentions. If you don’t push – and hold – the button long enough, the engine sometimes stays on. Or it comes back on (if you press the button too long).

You have to make sure the engine is in fact off in a way that was never necessary when keys were used to turn an engine on – and off.

ASS has compounded this problem by actually shutting off the engine  . . . temporarily.

But the ignition is still on – and if that’s not very deliberately turned off, the engine will come back on.


The driver – in a hurry or just distracted – rolls into his garage, his mind on other things. Before he even puts the gear selector into Park, the engine has already shut itself off. So he assumes it is off, doesn’t push the button to turn the ignition off, leaves the car and goes inside.

After a while, the engine he thought was off turns itself back on. And continues to run, emitting gasses that can lead to the Big Sleep.

An easy solution would be to go back to physical keys – which make infinitely more economic and functional sense than overteched fobs – and would eliminate the problem of engines that turn themselves on – and turn their owners off.

Physical keys are also much more durable and far less expensive than electronic key fobs and – being physical keys – will never stop working because the battery died or you put them through the wash.

Keyless ignition is convenient, of course. But how inconvenient is it, really, to put a key in a lock and turn it? Are we really that lazy? That gadget-addled?


So, rather than the cost-effective/simple fix we’ll get the complicated, expensive and wholly unnecessary one.

Discussion among the fatwa’ers is already under way. Instead of going back to keys, keyless ignition/ASS-equipped cars to have another system to warn drivers about the engine they just left running. Some of these would send a nag message to the driver’s phone – since he’s already left the car.

It makes me want to take the Big Sleep.

Wake me when it’s over.

. . .

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  1. It would be interesting to see a list of cars that still offer keys instead of those detestable FOBs. I viscerally hate the idea of having some stupid key fob in my pocket when driving. I want that crap out of my pants pocket. Sure you can take it out and put it in the center console, but what if you drop the damn thing between the seats or on the floor. This is something that you can’t do when the key is in the ignition. I would like to find the asshat who thought of this idea and beat the living tar out of him (or her). A real man does not like this one bit.

  2. all this insanity makes me remember the defintion of FASCISM:

    government control of private means of production

    If that ain’t what’s at the slime-coated bottom of this I have no idea what is. I’d suggest we start a new group called anti fascists, but it seems some bunch of morons have already coopted and perverted that name. Must live in Opposite World, cause that group are about as fascist as any I’ve known of in half a century.

  3. I’ve exited my car, (momentarily) forgetting to turn it off or remove the key. That’s what happens when you’re not paying attention–key or no key. It should be up to the market to decide whether ASS is worth the price and the hassle.

    • Hi Anon,

      My take: Things like keyless ignition are gimmicks conjured to get people’s minds off the fact that cars are largely perfected and that even the “cheapest” new economy car is more luxurious, in terms of its amenities, than most luxury cars were in the ’80s and prior.

      So, how to justify the price of the new car? The new higher-end car?

      Add gimmicks.

      Pushbutton was initially a feature in the higher-end cars. It is now common – and so, expected.

      This same process has happened with LCD touchscreens and will happen with things you don’t even have to touch – aka Gesture Control.

      Gimmicks, all.

      An entry level Corolla has climate control, power windows and locks, cruise, a great stereo… why buy a $40,000 Lexus?

      Other than just to spend the money?

  4. and then there is this–hearing-in-the-news/deaf-advocates-call-for-change-after-carbon-monoxide-death

    “Kentucky woman couldn’t hear keyless ignition warning.

    Connie Dotson arrived back at her home in Lexington, Kentucky last week and parked her car in her garage, the Louisville Courier Journal reports.

    She thought she pushed the keyless ignition button to turn off the vehicle. She headed inside and went to bed, not realizing her car was still running. Because she was deaf, she did not hear the beeping sound that alerts drivers that they need to turn off their cars.”

    and she died

    more at link

  5. The keyless ignition system is a perfect example of a solution in search of a problem. Like you said, Eric, how damn lazy do you have to be to find inserting and turning a key difficult??? As my mother would say, these people must need to keep kittens under their arms to breath!

    I remember the first time I saw a pushbutton starter on a car in a commercial. I thought, who’d want that??? But P.T. Barnum was right again. And thus we get unintended consequences like this. Or the other one I’ve heard of: Thieves stealing your car by amplifying the signal from your keyfob in the house. Then voila! open door, start engine, drive away. Until the carmakers come up with a way to avoid these problems (like maybe, oh, let’s say, A FRIGGIN’ KEY TO START THE ENGINE!!!!), I’ll hold onto my old car and keys, thank you very much. I’ve heard lots of other people say the same thing.

  6. Eric,
    As an Engine Mechanic back in the 70’s in my hippy days and as a Machinist since it is obvious to me a system that stops and starts an engine repeatedly will cause much more wear, probably intentionally as the motors were getting better with engine life from improved machining techniques. Less break-in time and wear.
    I have always known most of the wear in an Engine occurs at start-up, when no/low oil pressure and lubrication drained off. Definitely very bad for those rod bearings.
    30 some years ago, this even became a problem with some makes with prolonged idling, I remember when camshaft failures started happening from not enough reliable lubrication.
    I always ran Propane if I could buy it, the oil stayed much cleaner and no dilution, looks feel and smell would tell. No fuel pump, more reliable carb., instant warm up, fuel as a vapor. Much cleaner, low toxic to work on. Shutdown would rust out the head gasket from condensation, fixed with copper O-rings cut in block deck and copper head gasket I made, not too difficult.
    Also higher octane worked well what with Air-Research turbo and water induction on GMC 6 inline 302, milled head. think the comp was about 180#, 5 speed over Clark, Chev. 1 ton, 1925 chassis modified, dyno at wheels +100HP. Wooden + steel backed wheels. Was a lot of fun passing new Caddies uphill on interstate. 30 years ago.
    Sorry don’t have any pics,
    I now ride a bicycle.

  7. I had a mid-80’s Buick with automatic shut-off headlights. Scared the hell out of me, worrying that the battery would run down. Fortunately, there was a way to override the system and turn the lights off manually. After a couple of recent tragedies, legislators are planning to mandate some sort of warning system to remind parents that they have left their children in the back seat of the car. When you put the words “government mandated” in front of a mechanical or electronic “safety” device, you can start taking bets on how many people are going to die as a result.

  8. I’m beginning to see this more and more. Technology is becoming an incomprehensible joke. I used to always imagine some engineers laughing among themselves as I worked at trying to get some bolt out from behind some idiotic flange that blocked me from turning it more than a fraction of a millimeter at a time. Now I imagine a room full of morons slurping Red Bull’s, and scratching each other’s balls every time they come up with another idea that’s more idiotic than the last one.

    I have a weed wacker that requires me to purchase fuel that requires me to mix it with oil, and then use a nozzle that is guaranteed to safely spill fuel all over the place. Then I have to manually wrap plastic wire onto it which can take over 20 minutes sometimes. Then I have to prime it, and yank on it a few dozen times before it coughs. I have to wear protective goggles, long pants, long sleeved shirts, etc. As I wave this obnoxiously loud piece of crap, my arms, neck, shoulders, legs, etc. begin to slowly ache until eventually I start getting cramps, and have to see a chiropractor just to get some sleep.

    I also have a sling blade which I have returned to after a long break, and have discovered that the only thing I have to do with this thing is swing it like a golf club. So I can practice my golf swing and get some weeds cut down at the same time. No more trips to the gas station to get ethanol free gas, no more spilt gas all over the place, no more sore arms, legs, etc. I’m saving time, energy, and money on chiropractic care as well.

    I am seriously considering going back to riding horses again.

    • “…that blocked me from turning it more than a millimeter at a time.”

      Try that with a flare nut on a line going into a clutch slave cylinder. The EGR pipe goes right over the top of it. Turned a 3-hour (maybe) job into a three-day garbagefest.

    • Hi Jackal,

      Actually, your Tesla relocates this “problem.” Which, of course, isn’t really a problem – but rather an excuse to justify forcing most people into public/government transport or ride-sharing while the affluent elites drive around in electric cars.

  9. My car uses a key, which is perfectly fine with me since that is what I have used in my vehicles since 1965. I usually shut of the automatic engine shut off feature when the vehicle stops. I am not convinced that all that starting and stopping will not wear out the starter much sooner. Any money you might save on a few drops of gas will be paid out in 1 new starter. I believe that most new vehicles are not designed to idle for long periods, and I think this is stated in vehicle manuals. Long idling could wreck the Cats. Of course, non of this matters if people are being killed because of this drive toward technology and gas savings. Like everything else the government and socialists do, it has gone too far. So much of this new technology is not proven to last over the long run. So much of it is in the name of fake global warming as if the sun doesn’t exist nor do the facts. I almost hope I never have to buy another car with all this crap I don’t want to pay for or care about.

    • Hi Tom,

      The ASS system mainly decreases the service life of the battery rather than the starter. ASS-equipped cars have special high-torque starter motors designed for the purpose. But 12V starter batteries aren’t designed for repetitive starting – and discharge/recharge cycling. It wears them out faster. So you spend $100-something bucks for a new battery once every three years rather than once every four. Highly doubtful that ASS saves $100 in gas over the same timeframe.

      ASS may also wear out alternators faster, as they have to work harder to keep the 12V battery charged up.

  10. They could just concentrate on making a simple, quality car that would go 500,000 miles without a hitch but they won’t.

    • Hi Fred,

      Yup. As the intro to The Six Million Dollar Man used to put it, We Have the Technology. But that creates a problem… from a certain point of view.

      Ever read Huxley? He wrote about the need to waste wealth, in order to keep people busy. He didn’t mention debt, of course – and should have.

      That, in my view, is the real Oz behind the proverbial curtain. The point is to prevent people from relaxing; too keep them stressed out and working… to pay bills… so that they haven’t got time to think too much.

      See Carlin’s observation in re Obedient Workers.

      A $10,000 new car that gets 60 MPG and which is owner-repairable and lasts for 20 years or more is anathema to the PTB.

      • The Mercedes 300 SD from 1980 through 1985 cost about $7K new, yeah, it ONLY returned in the low 30’s for fuel economy, but I’ve known several to log well over half a million miles with only light naintainence done. Belts, hoses, brake pads, shocks, water pump, maybe a vacuum pump, clean the injectors every quarter million, and DRIve the stupid thing. Easy cruise all day long at 90, and, despite their 3600 lb kerb weight handle and perform like a fine roadster. but its a four door big sedan, quiet, smooth, comfortable…. one of the best sleeper cars ever.

  11. Though my Focus is a third generation (i.e. the newest one), the last redesign happened for the 2012 model year. Thankfully, it doesn’t have ASS, lane keep assist, reactive cruise control, keyless ignition, or much of the other nanny tech that’s in newer cars these days. I still use PHYSICAL KEYS! You know what? I PREFER physical keys, because they just feel right. I also like the inherent safety of physical keys vs. keyless systems.

    About two years ago, I rented a car that had keyless ignition. It was WEIRD! It didn’t FEEL RIGHT to just push a button and go; I’m totally accustomed to inserting a key and turning it before doing anything. Call me a Luddite; call me a reactionary; call me what you will; I still prefer REAL KEYS for my car! Then, I have no doubt when the car its on or off.

    When it comes time to replace my Focus, I don’t know what I’ll do. I’m hoping I’ll be able to find a good, low mileage car from the 00s or early 10s, so I don’t HAVE this BS in my car.

    • You also have ultimate control over who can start and drive that car because if YOU know where all both keys are at all times, no one can sneak the thing out of your yard with some techno mumbo jumbo hacking skills. If no one has that little metal blade to stuff into the hole and turn, then no one has the car. At least not without sERIOUS issues. I’ve had to deal with a lost key more than once…..

  12. You could pull the key out of the dashboard ignition switch on my 1965 Chevy pickup without turning it all the way to Lock. Thus most of the time, and especially when working in the woods, I never even used or carried the key at all and just started it and turned it off by turning the “flange” on the key(less) switch. At a glance to someone else it looked like there was no key (there wasn’t!) so no one thought about bothering to steal it – as if they would anyway since it was about 20 years old by that time. Sometimes in town I would just lock the door with the door key. That pickup was really advanced for its time: the carb needed work so sometimes it would automatically shut itself off at a stop light/sign, but it didn’t start back up automatically – you had to turn the key switch LOL

    I can’t remember if I also did that with my 1965 GMC 2-ton … I think it might have had a flush switch with nothing to hold onto without the key. Seems like my 1958 was like that but I’m pretty sure it had the starter pedal on the floor. Maybe only those old cars and pickups had the dash switch with the flanges that you could turn without the key (seems like the 59 Belair was like that ????)

    • Duh – just remember my first car was a 65 Impala! I’m pretty sure you could pull the key out of that one also without turning all the way to Lock.

      • Better yet, I knew guy who had busted the correct key off IN THE IGNITION LOCK. He was in a panic because he didn’t think he could start the car. So I reached in, grabbed the key switch by the ears, twisted it, and the critter roared back to life. Twist it the other way, it got real quiet all of a sudden.
        He drove that crazy thing for years, no one ever noticed the tiny brass nub still stuck into the key switch, so no one ever thought to just turn it. HE knew its fault/feature, and carried on. In those days GM had a different key for the doors, so he only had that key with a backup copy. Ignition never needed it. Great solution for a simple problem

        • Hi T!

          Been there/done that… the key breaking in the lock. JB Weld can fix that, usually. If there’s enough exposed stump, anyhow. Dab a little on there, along with something to grab hold of when it sets up. Leave overnight. Use pliers to remove.

          Worst case, pull the lock cylinder. In pre electronic cars, this is very easy.

          Which of course is why those cars were also so very easy to steal!

  13. I laugh everytime I see one of those POS lurch from a red light. It’s really hilarious what Americans will buy. I personally won’t ever buy another car. Too much useless crap and they look really REALLY ugly. Remote Start,,, LOL. You do know it’s illegal in some states to start your car with no one in it?

  14. It seems Hyundai has solved this particular problem with ASS. I was driving a rented Santa Fe, and pushing the shifter into Park automatically turned on the engine if it had been shut off by ASS.

    The car also had a fairly subtle restart – still noticeable, but not paint can shaker rough. I’d still prefer to be able to permanently turn it off, but then Hyundai would be setting themselves up for what happened with VW’s diesels, which might have passed muster if the default setting had the EPA’s shitty metric, but Sport or Eco settings had had the better tuning that got them in a world of hurt.

  15. Question….will the car restart itself if the departing driver takes the key fob away with him? Or only if the fob remains in the car? If the keys needs to remain with the car, this whole problem can easily be avoided. I “never” leave the keys in the car.

    A different danger is the Remote Start function, triggered by accidental pressure on that button while the fob is riding in a pocket. I’ve accidentally triggered that in my 2017 Grand Cherokee. Quite disconcerting to walk into your garage and discover the engine running. Owners manual “seems” to indicate my engine will shut itself off again after 15 minutes. Hope that’s right.

    Finally, your point about getting locked out if your remote fob’s battery dies may not apply to all that many cars. I checked my multi function fob, and discovered an old fashioned key discretely tucked into a small slot.

    • Most ordinary houses with attached garages are small enough that anywhere the person places the fob in the house is likely within wireless detection range.

    • I had a loaner Audi A5 for a time with a wireless key fob that unlocked/locked based on proximity. If the keys were in my 2nd floor bedroom of my apartment the car would unlock and could be started. But I guess it would shut off if it got out of range of the fob.

      The Cherokee won’t unlock until the fob is pretty close to the vehicle, pretty much in the garage and that’s it. If I get out while the engine is running (such as at the Costco windshield washing station) the thing goes into conniptions with warning chimes and red displays letting me know the key has left the vehicle. The remote start will work at some distance but I’ve not done much real-world testing. For sure it won’t work much further to matter much anyway.

  16. Someone I worked with at a former employer died of CO poisoning when he apparently “sat funny” on his key fob for his car. It started in the garage and he didn’t hear it. How many times have any of us sat funny on our keys and triggered the damn panic button–display of hands.

    My wife has a Camry Hybrid that can do this. I’ve mandated the thing sit in the driveway since the incident I mentioned above.

  17. Some manufacturers claim to solve the unattended running issue by use of the RFID system which implements immobilization features. However, if the key fob is left close enough to the car for the RFID sensor to sense its presence, even with the driver far away (if the key fob is routinely left on a table next to an attached garage door, for example), ASS could restart the car.

    And, all these RFID systems make getting a physical key cut a potential nightmare. Now you have to cut a key, AND program the key and/or the car’s computer! Such silliness!

    Throw ALL RFID/keyless ignition systems in the woods!

  18. The Cherokee’s ASS will only work when the vehicle is in drive. If you move the gear selector into park or reverse (and probably neutral) the engine will start back up again. If you remove your foot from the brake the engine will start up again. If I have ASS activated, when I pull into a parking space when I come to a complete stop the engine will shut down, but when I put it in park the engine starts back up again, then I shut down the engine. Very annoying and probably not doing the engine much good either. There were cases when I pulled in at an angle, and had to reposition the vehicle, which led to a number of stop/start sequences as I changed gears. That’s when I figured ASS was a wasted effort and began my normal start sequence of hitting the start/run button followed immediately by the ASS override button. Only a matter of time until I need a checklist to start the engine and enable all the overrides.

  19. With this ASS system I assume the car restarts *in gear* as opposed to old style if the car stalled you would have to place either in park or neutral to restart? So if you are in grid lock traffic and everyone gets out to stretch your legs (sometimes happens major accident, etc) will the car restart and move forward if the kids touch the gas peddle? My god, someone will be killed!! We need a new group: Mothers Against ASS Driving.


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