The cam/crank PID is in live data on scan tool Pete and just literally says yes or no whilst cranking.

Also looking at capacitor voltage is a very good idea

A capacitor is a way of storing electrical energy in live data if your capicitor voltage is low you need to check all the injectors/injector circuit for outside interference.

I'm currently reading a good book called automotive electricity and electronics by James D halderman which has a really good description of how capacitors work

If you are interested when I get time later I will post his description of how/why capacitors work

Regards
Carl