An engine analyzer is a complex, mult-function instrument, sometimes called a scope, that can help diagnose engine and engine-related problems or assist in tuning following an overhaul. An engine analyzer can be used with gasoline and diesel powered vehicles.

Among the components and test capabilites it may include are pressure and vacuum gauges, a tachometer, a timing light, a voltmeter, ammeter, and ohmmeter, a vacuum pump, a cylinder output test, an exhaust/emissions analyzer, and an oscilloscope.

An engine analyzer is connected by a variety of means, including leads, inductive clamps, and probes to the various engine parts from which it gathers data. These data go to a computer, or set of computers, and are compared with manufacturer-supplied data for that vehicle held on disk or CD. The analzyer processes all the information and presents results on the state of the vehicle's engine condition (identifying, for example, any uneven balance between cylinders, worn timing chains, and compression problems), fuel system, electronic control system, emission levels, battery, charging system, and primary and secondary ignition systems.