Engine Control Unit (Ecu)
The ECU controls fuel injector pulse width and ignition timing based on inputs from various sensors and switches. Sensors monitor exhaust gas oxygen content, air/fuel temperature, coolant temperature, manifold absolute pressure, battery voltage, crankshaft position (engine speed) and throttle position. Switches provides ECU with informations on power steering pump output pressure, wide open throttle conditions and transmission gear selection (automatic transmission only). Battery voltage is also monitored to determine injector pulse width.
NOTE:
The various components are grouped into 2 categories. The first category, INPUT DEVICES, consists of components which control or produce voltage signals monitored by ECU. The second category, OUTPUT SIGNALS, includes components that are controlled by ECU (this is usually accomplished by ECU grounding individual circuits).