Instead of having individual fuel injectors for each cylinder like more modern multi-port fuel injection systems, TBI used a single injector located in the throttle body. This injector sprayed fuel into the intake manifold, where it then mixed with air before entering the cylinders.
TBI systems were a significant step up from carburetors, offering improved fuel efficiency and emissions compared to carbureted engines. However, they were less sophisticated than later multi-port injection systems and generally considered less precise in fuel delivery. This resulted in potentially slightly rougher idle and less precise air/fuel mixtures under varying conditions compared to more modern systems.
