James,

the problem is, that we have much too little information, to really give help!

You told, that an inductive sensor gives you the pulses. But it's not clear up to now, whether they come directly from a coil or a Hall-sensor. If signal comes from a coil, amplitude highly depends on rpm! So, when you tell your signal is 0.8V, then we should know at what rpm!

If you have a Hall-sensor, then 0.8V signal amplitude is definitely to little. I guess, that in any case you short circuit whatever gives you the pulses, by choosing a much too little load impedance.

Generally spoken: If one takes into consideration, that spark voltage is several thousands of volts high, a signal with amplitude of only some hundreds of millivolt is way too little, whatever system or methode is used. What we need for a signal must be in the volts range, what a standard Hall-sensor delivers.

Kai