Abstract: An improved automated engine diagnosing device employing a digital data processor and a cathode ray tube monitor for displaying individual engine cylinder numbers in separate association with correlated values of exhaust gas emissions pollutants. Engine timing data associated with the time of firing of individual cylinders of the engine being tested synchronizes select cylinder firing inhibition for orderly accumulating gas emissions data generated from an exhaust probe placed in the tail pipe of the automobile under test. An automatic sequential firing inhibition and a manually selectable firing inhibition permits dual modes of data acquisition for developing pollutant data to be utilized by the processor for generating the analysis display on the cathode ray tube monitor.

Abstract: An engine tester for determining relative compression by cylinder is disclosed. The tester includes a processor which samples starter current in response to input signals based upon engine cylinder firings. The processor correlates the starter current data and the input signals to identify the current by cylinder.