General System Description

ECU Under Dash:

The PGM-FI (ECU), located under the carpet on the passenger floorboard, is the primary controller for the fuel system. The ECU itself consists of a dedicated microprocessor, a small amount of volatile memory, and the control program contained in read only memory (ROM). The ECU monitors the absolute manifold pressure and the engine speed to determine the basic "ON" time (amount of time the injectors are open and injecting fuel) for the fuel injectors. Before the ECU actually alters the injector "ON" time, the other data inputs (intake air temperature sensor, oxygen sensor, etc.) are used to determine the final air/fuel mixture. After the final "ON" time has been determined, the ECU then applies this to the injectors. For a more detailed explanation of the ECU function.