Its not the time you test ist the max gap
I was told that often you can start your car or bike and everything seems OK and then 10-15 minutes later a coil starts malfunctioning.
I once walked into a workshop dedicated to testing electric automotive parts like starters, alternators and the like. It was an oldfashioned workshop, a 10 min walk from where I lived, with big oldfashioned analogue gauges. I was there to ask something for my yacht's alternator. In the background I heard a high tone and mixed with the smell of electric gear, I also sensed ozon. When we walked towards the bench where the sound came from, I saw an automotive coil being tested. The man explained the ultimate test for a coil is running it for some 15 minutes.
I remember I once have asked Ashimoto (UK forum) this, but he never came with an answer.
Hence my question if nowadays there maybe is a cheap electronic device that can mimick the primary circuit. Would be great if we could evade all these posts about coils for once and for all.
Many devices can generate a 5V logic level signal.
Many modern coils have an "igniter" included that will let you drive them directly with that signal. You can also buy that Bosch igniter as a separate part and use it to drive any kind of coil.
There are some OEM parts avail that can be used as coil drivers
But this will work and is way cheaper :-).
https://www.diyautotune.com/product/coil-driver-kit/many folks in the tuner ECU community will increase dwell time until the coils start to get warm and then back off a bit.
You can buy an arduino clone for about $10, then buy the coil driver kit above and rig up a tester for $20, I was able to borrow the scope from work.
But a junk blown up lawnmower engine that the crank still spins on would give you a set of points you could operate at any rpm too ;-).
