Electronic Control Unit
The Electronic Control Unit (ECU) is a pre-programmed analog computer which is installed in front of heater housing and below radio or above glove box. See Figs. 5, 6 and 7. It is electrically connected to vehicle power supply and to the components of the electronic fuel injection system. As signals are received from the sensors, ECU processes the signals and commands injectors to open for a specific time duration. The duration of injection (pulse width) varies as the engine operating conditions change. The desired air/fuel ratios for any possible combination of driving or atmospheric conditions are programmed into the ECU.