It is dark so the lines aren't visible but you can pretty much tell what is going on without them. I had it on 50ms at the start then changed it so a single pulse could be seen. I switched it to ground and back so you could see where 0V was at on the scale. The zener is pretty much only cutting off the 14V spikes and not doing much else it looks like. If I had a second probe I could have measured before and after the filter at the same time. I might do that next week when I can pick up a second probe from school.
Looks about the same as before the zener/resistor but there is even less of a difference between on and off. I did notice that at idle the 10x probe was loading the circuit enough to make it read 99% duty cycle. It would go back to normal reading when off idle. I am kind of surprised it even can read a signal like that and get any useful data out of it. It might only be reading the curve of the peak and not the sustained injector hold signal. That would possibly explain why it has such a narrow range of values it reads. I am just guessing about that though