Abstract: A method for the analysis of performance characteristics of a vehicle includes the measuring of a plurality of performance variables over the course of a predefined test protocol, typically providing for the variation of operating parameters during the duration of the test. Each variable is compared to an appropriate reference at a chosen number of points or "test sites" during the test, and the results of each comparison is classified as being above, below or within tolerance. The comparison results are tabulated into a value matrix. The matrix is compared to a series of reference matrices, each of which is associated to a different cause, such as bad timing, fouled spark plug, poor cylinder compression, and the like. Association of the values in the matrix to a reference matrix allows the problem as reflected by the measured performance variable values to be identified.

Abstract: A method and apparatus for testing vehicle fuel tank integrity determines the free space in the system by pressurizing the system with a known quantity of gas. The loss in pressure over a test period is then monitored. These data are used to calculate the size of the leak. Alternatively, the free volume is compared to a reference volume and a normalized leak rate computed for comparison to reference values.

Abstract: A method and apparatus for the testing of vehicle fuel tank caps includes the mounting of a cap to be tested upon a mating socket. The socket/cap combination define a sealed chamber which can be pressurized and/or evacuated in a controlled manner. A pressure transducer monitors the pressure within the chamber. The monitored pressure is compared to reference values to determine cap integrity. The apparatus may be incorporated into a vehicle testing system using microprocessor control and having a database of vehicle, cap and performance data.