Abstract: A method and apparatus for the operational state analysis of internal combustion engines with electrical ignition systems wherein, following any deviation from normal engine operation, the cause of the deviation is determined and localized in the engine. Provision is made first to ascertain with good time resolution a numerical value of speed by measuring the time interval between two consecutive ignition pulses of different cylinders and then to determine a second numerical value which includes both the count of the number of ignition pulses and the cylinder designation, both numerical values being stored in digital form over a substantial length of time. The engine speeds for the particular cylinders computed from those two numerical values being graphically displayed in the time sequence of the ignitions as an electronically generated stationary image.