Aftermarket Tachometer

[Burning Pyro]

I bought a Prosport Tachometer and was trying to throw it into my gauge pod.its god 4 wires: Red=12v constant, yellow/orange=illumination, black=ground,and green is what makes the actually tach work. I thought i had it figured out, im pretty good with wiring,i thoguht maybe try running the wire to the ecu rpm line....that failed, i tried the second rpm line and yet again failed. i tired both together and the car didnt like and would just crank lol. im going off my safc II wiring guide and it shows just the only 2 rpm lines, im going to see if i can find an ecu wiring diagram, but in the mean time, any advise or if anyone knows how to make it work it would be nice if you could share, little hard to race w/o the tach working. I'm riding in an 88 Turbo Supra w/Targa. Thanks!