Abstract: Electrical pulses are provided to the system as each piston of an automotive engine reaches its top dead center position during a compression stroke. The system measures and stores the time TP which is equivalent to the elapsed between a first and second pulse. The system then measures the current cycle time, TC which is the time accumulating after the second pulse. To this time TC the system instantly adds a predetermined and constant (but adjustable) time advance period, TA. The time TP is fed to a comparator for comparison to the total of the time TA plus the accumulating time TC. When the total of time TA plus the accumulating time TC reaches the value of the time TP, the comparator generates a pulse to fire an automotive ignition coil. When a third pulse arrives the system stores the new value reached by TC as the new TP for the following cycle. Thus, the result of this addition of TA to TC is continuously compared with the stored value of TP, and when the two values coincide ignition is again triggered.