Found this
link that dcb had posted in post #31 in this topic
It describes two types of Peak and hold injectors. The other's hold part is done with limiting the injector current and the other one's hold is done with PWM signal. PWM means that the current is switched rapidly on and off.
I have the PWM version P&H injectors and the filter works with them.
One possible way to see which type of P&H injectors are in your car is, if you have the mpguino connected to your car:
1. Set the injector delay to very small (like 2us)
2. Start the car
3. Check the MPGuino RPM value. If the reading multiplies when loading the engine with low rpm, then it probably counts the short pwm pikes as different pulses.
Good luck Cheese!
