Ae86 tacho

[jondee86]

I don't know of any reason why applying 12V to the tacho input wire
would cause it to fail. But since you have done a 4AGZE DLI conversion,
you are most likely trying to get the tacho to work with the 4AGZE igniter
tacho output... and that won't drive the tacho. AFAIK the 4AGZE tacho
output is low level (5V) and the AE86 tacho needs a voltage spike (>30V)
to make it work.

You will need to either change some resistors in the tacho driver board,
or obtain a voltage spike from the negative terminal of both coils and
combine the output using diodes. You can find information for both
methods on the interweb.

Cheers... jondee86