When I was about nine years old, I was riding in the back of my family’s old ’68 Volkswagen Beetle when the car started to lose power and slow down. My mom, who was driving at the time, began to pull over to the side of the road, and at that moment I looked behind me, out the back window, to see an ominous column of smoke emerging from the back of the car. That was my first car fire!
And while I haven’t really had a full car fire since then, I have had plenty of cars that seemed more than willing to give fire a chance. A Volvo P1800 with twin SU carbs that loved dumping fuel on a hot exhaust manifold, brittle fuel lines hiding under braided fabric covers just waiting to drip onto a hot muffler, and so on. Basically, when it comes to older cars, they almost always seemed like it wouldn’t take all that much to get them to ignite, really.
Except, of course, for when they were off. And that’s what’s so different about what’s happening now to over 3.2 million cars that have been saddled with NHTSA “park outside” warnings. Because those cars, be they Jeeps, Kias, Hyundais, Chryslers, BMWs, and more, are all at risk of catching on fire while they’re off. So what the hell is going on?
Well, I talked about this in at least a little bit of detail with Flora Lichtman of Science Friday, who was kind enough to give me some leeway to rant like the cranky old bastard that I am:
That’s the whole episode, which includes a compelling interview with a food safety expert, for those of you interested in avoiding long, languorous drives down the Highway of Hershey, but if you want to be rude and just jump to the segment about cars, I guess you can jump to timestamp 14:18.
If you’re opposed to listening to that at all and prefer to listen with your eyeballs, using an exotic technique called “reading,” then I suppose I can recap the essence of what I was going on about.
So, why are all these cars catching on fire when they’re not even on? They’re all fuel-injected, so no leaky carbs, and they’re all relatively new and modern – you’d think this would be a very solved problem! But the problem is more complicated than it seems, and it’s from our own doing, really. The reason cars are catching fire when off and parked is mostly because modern cars are never really “off.”
If you want your car to, say, detect your keys when you approach and illuminate its lights seductively and unlock itself, or protect itself from intruders when it’s parked, or use its cameras, or get over-the-air software updates or any number of other things cars do when not being driven, then you have to accept that your car is still on, at least electrically, when it’s been turned off.
The engine may be off, but modern cars still have plenty going on, powered by their 12V battery (or a larger battery in the case of hybrids or EVs), meaning that there are many, many circuit boards and wires crammed deep within these cars that are hot, electrically. And components in cars are packed together incredibly tightly, especially in the case of hybrids, which means that there’s a lot of opportunity for parts and fluids and other bits to interact in unexpected ways.
For example, the issue with Jeeps has to do with the power steering system, an Electric Hydraulic Power Steering Pump (“EHPSP”), that can have electrical connections of very high resistance that can generate heat, and it’s close enough to other components that it can catch things on fire. The Kia recall is focused on a power seat motor that can be stuck on and generate heat and set things on fire, others have wiring that is hot and in the path of potentially dripping brake fluid that can cause a short and create sparks or resistances that can set things on fire, and so on.
While these details differ, the fundamental causes are all essentially the same: cars that are “off” are full of flowing electricity, and whenever you have that near flammables like fuel, a risk of fire exists.
If all this makes you nostalgic for a time when you turned a car off and it was really “off,” you’re not alone. But, like so much in life, we’re here because of tradeoffs and compromises. You want the convenience of keyless entry and security systems that work? Then the car needs to run sensors and computers and RF transceivers and more while parked. The reason we haven’t seemed to fully solve the problem of keeping cars non-aflame while parked is because we’re constantly making the problem harder.
Of course, that’s no excuse! Car makers should absolutely be able to make cars that don’t spontaneously combust while just sitting there! That feels like a pretty mild ask, really.
Anyway, thanks to Science Friday for indulging my ranting.
Top graphic images: Stellantis; DepositPhotos.com
The primary issue here is that TOO much remains powered, at all times. It’s common today for a 2020+ car to be dead if it sits for a month, because there’s a constant 100-200 milliamp draw on the 12v batt, which by the way does not charge while ‘key off’ in the majority of hybrids or EVs. On old cars, that draw is closer to 60-80 milliamps.
For every one of these vehicles, everything should be de-energized except for the keyless entry module, the module controlling cellular access, and the module watching cameras, if present. Once one of those triggers a wake up, only then should other components be powered.
Of course when Jason gets on NPR, it’s on a show about spontaneously, combusting, automobiles, and spontaneously, explosive diarrhea.
I haven’t listened yet but the opportunities for an epic segue are abundant.
Of course I’ve had car fires. How else is a budding carburetor tuner supposed to learn?
“You want the convenience of keyless entry and security systems that work?”
No, no I do not.
Yeah, car security systems only serve to annoy the neighbors in the middle of the night when I accidentally set it off…
I figured it was people underwater on their payments looking for a way out.
My 69 Beetle was my first car fire, too. However, it was just the fusible link burning because the air filter assembly fell off on a big set of RR tracks in Raleigh and shorted against the alternator (yes, that it correct, I put an alternator on my bug because the generator had so little output the car would turn off due to lack of power while I was thumping my subs.) I solved the problem by getting a set of dual Solex 32 carbs for it, which got rid of the stock air filter. Did make me miss a lab at NC State because I was stranded on the side of the road.
I once had an under dash wiring fire in a truck. Use the dry chem extinguisher to put it out. My boss got mad at me for making a mess of the cab. I told him if there’s a next time it’s going to burn.
Welcome parasitic power drain, hello dead battery. Another reason to use a trickle charger for cars that are not driven regularly.
You missed the part where a dead lead acid battery is incapable of starting a fire on your parked and unsuperviced car.
Its also incapable of being a battery anymore.
I always wait like a minute or two getting my stuff together in the car when I turn it off, then when I walk outside of it, I pay attention to any smell or something off (either a noise from a relay or whatever may be clicking). When the car locks I look back again making sure nothing seems different.
No no no, I never wanted ANY of this stuff. But carmakers don’t give you a choice anymore (consumer choice costs money and that’s bad!) and increasingly they see the vehicle as NOT “my transportation device that I bought from them and now belongs to me and should do what I want it to do” but rather as “their data-harvesting device that they ‘own’ and should do whatever they want”
This is what I find appealing about the Slate – none of that stuff. It feels a lot like the EV version of my ’95 Tracker, which was my mostest favoritist car I’ve ever owned.
If they come out with a 4 door (or better, a van), I’ll be very interested.
I’m lucky; I’m beyond the point where I need the extra doors and seats. If I were in the market, I’d have reserved one already.
Yeah, if you don’t need a back seat, it’s a neat little truck!
My dad’s ’always carry a fire extinguisher’ rings in my ears to this day. We once stopped to put out an engine fire in a Fiat 850 on the Beltway. The driver would cover the engine in towels overnight because it wouldn’t start if there was condensation. Guess who forgot to remove the towels that morning?