Abstract: An automatic calibration selection for an automotive control system allows the use of one basic electronic control unit (20) for a family of motor vehicles. In each motor vehicle, a unique valued resistor (10) is located in or adjacent to the wireharness and near the electronic control unit connector (12). This resistor (10) provides an input to a voltage divider network to select a voltage value representing the particular control parameters for the vehicle. The voltage operates to address (24) a read only memory (22) to place the proper calibration constants in the electronic control unit (20).

Abstract: A digital-analog fuel injection system wherein fuel lean out is controlled by a fuel mapping circuit 36 which provides one of sixteen levels of percent lean out control of the fuel pulse width supplied to an injector. In order to provide an immediate update of the engine demands, a pulse generation circuit 72 operates in real time. The fuel mapping circuit 36 provides corrections to the pulse generating circuit on a sampled update basis. This is accomplished by using a digital word 34 generated by a microprocessor 10 to control a multiplying digital to analog converter whose reference input is an electrical signal (V.sub.MAP) representing the present manifold pressure and an offset voltage (V.sub.O) accounting for the several variable of the system such as the engine, injectors and pressure sensor. The output signal (V.sub.B) from the fuel mapping circuit 34 is then applied to a pulse generating circuit 72 to control the generation of fuel pulse width which is being applied to a fuel injector driver 46 (FIG.