matrix 100 upon coincidence of the signals on line 114 and line 118 the coincidence detector and bulb driver 116 provide an appropriate potential to light a lamp 120 consequently while synchronization is established between the selected crankshaft rotational position and the generation of a pulse corresponding to the selected rotational position of the crankshaft the synchronizing lamp 120 will be lit synchronism is initially established by closing a switch 122 which resets flip flops 96 and 98 to provide an output pulse for switch 2 when the proper rotative position of the crankshaft for firing is detected by the capacitive pickup clip 112 switch 2 then controls the pulse initiated by the normal firing time of cylinder 1 so as to insure either the presence or absence of supplementary advance to the second cylinder in the firing order thereafter synchronism is maintained although the switch 122 is disconnected through counting of the occurrences of distributor contact opening in summary of the operation of the system 10 the opening of the points 16 provides a pulse 14 which is used to control the firing of the advanced as well as the non advanced cylinders considering a cylinder which is not supplementarily advanced as indicated by an open switch 92 for that cylinder the pulse.