Old Cars

It’s not that I’m worried or anything, or keep thinking about this stuff even though I deliberately changed my habits…

Joy to Robbie:
I think I asked you this before but I don’t remember.
What is it exactly that they made electronic in car engines that would be affected by an EMP? I had a thought to be informed about which cars would still work, and didn’t know what to search for, to find out when they started putting whatever on all the cars.

Robbie to Joy:
Cars have always had high voltage coils that provide power to the spark
plugs. It’s possible that a big enough surge could burn that out,
considering that solar flares caused fires in telegraph stations in the

In the 1970s they started putting electronic ignition on most cars,
which means that the spark timing is electronically controlled instead
of mechanically. This type of system seems like it would be more likely
to get fried because it has smaller wires in the control circuit.

In the late 1980s they started putting fuel injection systems in cars,
and by the early 1990s just about all of them had fuel injection. The
engine is controlled by a computer that receives data from a variety of
sensors in all parts of the engine. This technology is a great leap
forward in efficiency, reliability and durability, and it’s the norm in
all cars. There is also a body control computer that handles all the
other functions in the car such as air conditioning, automatic locks,
not letting you start the car unless everything is in the right place,
and generally trying to be smarter than the driver. This kind of system
is ridiculous, and I wish it didn’t exist.

In modern cars also, automatic transmissions are controlled in harmony
with the engine, by the computer.

Considering that gasoline engines have always had electrical wiring for
the spark plugs, the only way you’re going to have a car that’s immune
to the theoretical EMP disaster is to get a diesel. Presumably the
modern ones have computers that control when and how you can do
everything, as well as computerized transmissions, but if you get a
stick shift you can probably drive it after you bypass whatever gadgets
are there to tell you when you can start the engine. Mostly this would
be a fuel cutoff solenoid and some kind of switch in the starter
circuit. Presumably a pre-1990 diesel car would just start up and go.
The 1970s Mercedes engines had a mechanical fuel shutoff, but I don’t
think the old VW Rabbits had that. It would be easy enough to get
around that kind of thing, though.