can't get this to work. it's swapped engine and tach is classic instruments tach. car previously had 0411 pcm and with 6/6 it was working.
now has 4896 to match the engine/trans but can't get tach to do anything.
don't know if it has pullup resistor or not.
i've read all the posts for math on how to set it.
i've tried
1/1
2/2
3/3
etc stopping at 12/12
also tried
12/1
11/1
10/1
etc until 2/1 and still nothing.
is there something special about the 4896?
please help!