Have you ran the lead to the second P-Mag?
Try removing the additional filter to see if the filter is damaged.
Remove the signal line and tap it to +12v and see if you get pulses on your EFIS.

You could switch to the 5v signaling (install diode) and move pin 33 back to pin 32.

Alternatively, our 71420 RPM Interface board allows for a dual P-Mag installation using Pin 32.