The 'Third Generation' of Honda Preludes refers to the models marked with years 1988 thru 1991.
Most modern cars contain large quantities of electrical componentry, and 3rd generation Honda Preludes are certainly no exception. Because of the relatively high level of sophistication and gadgetry carried around by 3rd gen Preludes, they are home to a mountain of circuits, wires and sensors. If one is to tackle projects aimed at repairing or improving Honda's electrical design a certain amount of research must first be done.
A Prelude's ECU (along with its attached sensory components) can generally be thought of as the most critical electronic component in the vehicle as it enables the engine to function properly. After all, a car isn't that much fun if you don't get to drive anywhere. Most 3rd generation Preludes equipped with Honda's PGM-FI use an OBD0 ECU identified by the code PK2. The PK2 ECU comes from a family of similar OBD0 Honda ECUs that support Honda engines of a similar period that are also equipped with MPFI (multi-point fuel injection).