Which wire from the ECU do I tap to use for aftermarket Tach signal 1990 240 24e

[MTC]

I cant find The wiring scematic on my alldata and the tech people for my tach dont have a clue! Pictures would be great!IAlso if there is another way then cool My aftermarket tach says to hook up at the tach signal port.

Modified by MTC at 6:43 PM 12/26/2008
Modified by MTC at 7:16 PM 12/30/2008

[idriftnsj]

the easyest way to hook up a tach on a single cam is to tap into the green wire with the black line on it running to the coil under the hood