Abstract: A diagnostic apparatus for an internal combustion engine ignition system measures the rise of the secondary voltage at the ignition coil represented by time lapse between initiation of the secondary voltage rising and occurrence of break and the ignition coil primary breaking current value. Results of the measurement are computed to determine stray capacitance existing in the internal combustion engine ignition system and secondary voltage.

Abstract: A device for preventing a fixed angle change of a distributor in relation to an engine. The distributor includes a cylindrical portion, through which a rotor shaft is pierced, and a flange formed on the cylindrical portion. The cylindrical portion is rotatably fitted into a fitting hole formed in the engine while the flange is seated on the engine. A fixing block of substantially hexahedron shape having at least one thrusting projection on either side surface is forcedly inserted into an arcuate elongated hole formed in the flange by means of fastening a bolt pierced through a circular hole formed in the fixing block. The thrusting projections intrude into side walls of the elongated hole for preventing movement of the flange in relation to the fixing block which is firmly fixed to the engine by the bolt.

Abstract: An ignition system for internal combustion engine, which controls the ignition coil primary current according to the magnitude of the floating capacitance in the secondary side wiring section of the ignition coil, by determining the floating capacitance from the negative slope of rising of the secondary voltage produced in the ignition coil in response to the cutoff of the primary current and the primary cutoff current value, the slope being determined by measuring the period T until the secondary voltage reaches a predetermined voltage value. When the floating capacitance is increased, the primary cutoff current value is increased to increase the coil energy so as to increase the secondary voltage generated in the ignition coil for preventing the generation of a miss-spark.

Abstract: A fixing device used for a distributor which includes a cylindrical portion, through which a driving shaft is pierced, and a flange for fastening the distributor to the engine with a bolt. The fixing device consists mainly of a pair of container-like covers to be faced to each other with an opening portion thereof for being fitted, one into the other, to untouchably cover the head of the fastening bolt. Both are provided with a bottom plate and a side wall and one of the covers is further provided with a through-hole in the center of the bottom plate for being pierced by the fastening bolt. Both covers are further given necessary dimension to be mutually fitted, one into the other, and accommodate the head of the bolt in the enveloped space between the both covers. Either one cover is provided with engaging tongues for engaging with engaging portion(s) formed in the side wall of the other cover.