Let use a pulse(delta sensor) and the wps500x to look at injector pulses in the fuel rail by connecting to the fuel pressure regulator vacuum port. As each injector fires we should see a change in the waveform.
If you are synchronizing your signal to a injector make sure you use an attenuator if needed. Injectors will often spike up to 100V.
I used the Nicholson pulse sensor and the WPS500x Zoom 3 for the testing in this video.