tach not working

[nismo93s13]

ok, i finally got my AT-MT swap done. i got it to run by hotwiring a couple wires, thanks to Nick aka 574-240sx. but now, the tach doesn't work and the fuel gauge keeps going up past the full mark. the only thing on the dash that does work is the temp gauge.

is it because of the fact that im not using any of the sensor wires from the transmission? (the MT wires/plugs dont fit). is it just because the 5th gear sensor isnt't hooked up? something else?

i already checked the dash fuse and it was fine. i was thinking of hooking up one of the sensor wires to the tach wire at the ECU, but dont know which to use.

i haven't took it out for a test drive yet, but will do so sunday morning.

TIA david s.nismo93s13