RPM

I have the same problem with my R33 GTsT. After I installed my Apexi Power FC, the factories tachometer stopped working. We reinstalled the cars ECU, and the tachometer was working well. With the Power FC installed I only have a RPM readout on the Hand Controller. Does anyone how to get the factories tachometer to work in the dash board, using the Power FC?? Thanks in advance. Re Maikel