Originally posted by Streets
TBI=Throttle Body INDUCTION! IT injects nothing at all, the piston going down in the cylinder with the intake valve in the open position SUCKS the fuel mixture into it Peroid...
Clip taken from Automotive Technology - A Systems Approach Written by Jack Erjavec and Robert Scharff

Throttle Body Fuel Injection

For many auto manufacturers, throttle body injection (TBI) served as a stepping stone from carburetors to more advanced port fuel injection systems. TBI units were use on many engine during the 1980's and are still used on some engines. The throttle body unit is similar in size and shape to the carburetor, and like a carburetor, mount on the intake manifold. Fuel supply and return line service one or sometimes two fuel injectors. The injector(s) spary fuel down into a throttle body chamber leading to the intake manifold. The air/fuel mixture in the manifold feeds all cylinders.