WARNING: This page is about a different car, the 2005 Mazda RX-8 and 2004 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.
Terminal connected:
FS: 2G (+)-Negative battery terminal
RS: 2D (+)-Negative battery terminal
Oscilloscope setting: 5 V/DIV (Y): 5 ms/DIV (X), DC range
Measurement condition: Racing after warm-up (no load)
Fig 1: Identifying Fuel Injector (FS, RS) Control Graph