Modify engine timing by fooling the ECU of the hall sensor pulses.

[jtanguay]

Does anyone know of the easiest way of modifying the pulses coming from the hall sensor for the crank position sensor to either increase/decrease engine timing? I'm assuming a 555 timer circuit would be capable of this, but does anyone know the circuit required?

I found a company that can actually re-program some functions of the ECU right through the OBD-II port. I'd like to know how to tap into that myself and really start messing with the parameters. Would be nice for plasma spark etc. The link is here.

Thanks