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TR2/3/3A Back to my ignition coil education


Jedi Warrior
I stated previously that my 3.0 ohm coil failed recently. I replaced it with a 1.4 ohm coil. It may be my imagination, but the car seems to fire up a little quicker (with the full 12 volts to coil). I understand that many earlier cars had full voltage to the coil in "start" mode, but reduced voltage in "run" mode. I've placed a 1.5 ohm resistor in the "key on" wire to the coil. Would there be any real advantage to running a parallel wire from my starter button to the coil? Over thinking?



Great Pumpkin - R.I.P
No reason you can't try, if you want. Note that you need a diode or relay, though, as otherwise the solenoid will be shorting out the coil when you release the button.

It was actually later cars (TR6 started in 1973) that used the external ballast and shorted it out during starting. Mostly an emissions thing, IMO, as the emission controls during that period made them harder to start. But it was pretty much the standard configuration until electronic ignition with adaptive dwell took over; which is why FLAPS generally only have the 1.5 ohm coils. My Stag had it originally, but when the wire broke I just left it disconnected. Couldn't tell any difference, but I've never tried starting it in below freezing weather (when it's needed the most).


Jedi Warrior
Yes, I just realized the starter solenoid would be energized as long as the key is on. I think I'll leave well enough alone.
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