An injector driver module applies power to a fuel injector of an engine for a fuel injection event. A voltage measuring module measures first and second voltages at first and second electrical connectors of the fuel injector. A parameter determination module determines a maximum value based on a first difference between the first and second voltages, determines a minimum value based on the first difference between the first and second voltages, and determines a second difference between the maximum and minimum values. A diagnostic module, based on the second difference between the maximum and minimum values, indicates whether the fuel injector injected fuel in response to the application of power.