of interest so as to focus upon a compression sample period and a firing sample period for those particular cylinders referring again to fig6 the composite signal waveform shown in curves b and c may be analyzed with respect to cylinders no 1 and 2 in the region of the top dead center position of cylinder no 1 the waveform form is analyzed to determine a best fit approximation of the slope of portions for a compression sample interval and a firing sample interval delineated by intervals d and e similarly although its respective compression sample and firing sample intervals are not delineated in fig6 cylinder no 2 may be analyzed from the same composite waveform by evaluating the slope of the composite curve within the region of the top dead center position of cylinder no 2 which is separated by 90 u00b0 from the top dead center position of cylinder no 1 so that a determination of the characteristics of cylinder no 2 may be obtained from the same waveform that produces characteristics for cylinder no 1 referring now to fig4 a 4b 5 and 6 it will be assumed that the signal analysis program stored in rom within the processor 100 analyzes the cylinders in succession namely beginning with cylinder no 1 and ending with cylinder no 16 for the sixteen cylinder engine of interest in this regard the characteristics shown in the table and fig5 and the stress waveform shown in fig6 corresponds to an emd 645 e3 engine considering cylinder no 1 as the first cylinder of interest processor 100.