Hi,

Maybe I am missing something, but when you mount the sensor could that be made adjustable?

2.5 volt input will need to use comparator on chip.

Why not just use a LM324? 4 channels. One could be used as a comparator out put to another channel via RC network for the delay. Out put from here to a IGBT for speed and power to the coil.

Get all of this working and then tie into a PIC for auto retard/advance control for different loads on the engine.

???