The early fuel injection engines that were introduced in the early 1980's were mostly based on the "throttle body injection" systems (TBI). These early fuel injection engines were of two basic types, direct and indirect fuel injection systems. Later came the "multi port fuel injection" systems (MFI or PFI) and this injected fuel directly into the cylinder head. This system was known as a direct injection system. All of which were a great improvement over the traditional carburetor.

The throttle body injection system was the first fuel injection system used in passenger vehicles. It was very cost efficient to produce but wasn't the most fuel efficient system available. The throttle body injection system was basically a carburetor that was electronically injected with fuel. This system gave you a better air fuel mixture than the carburetor but not as well as the multi port system that came later.

The...