1986 Jaguar XJS

ELECTRONIC CONTROL UNIT (ECU)
The ECU utilizes an integrated circuit containing the digital fuel injection control chip and an analog-to-digital converter to translate information from the sensors. The fuel injection program is stored in a Read-Only-Memory (ROM) chip.
For any given manifold pressure and engine speed combination, the memory provides a fuel injection duration for optimum combustion. The ECU also monitors other sensors to modify the basic speed and pressure signals so that cold starting, mixture adjustment and other areas of engine operation can be controlled.