What is TBI or Throttle Body Fuel Injection?
[back] THROTTLE BODY FUEL INJECTION– The throttle body injection system is one of the first mass-produced fuel injection systems in the US auto industry, and is the most cost efficient system. If not for more stringent emission standards and second generation onboard diagnostics (OBDII), it more than likely would still be widely used. Some of the original designs were developed in the early 70’s by GM’s AC Delco division anticipating the upcoming emissions standards change. Some of the first applications were found with Cadillac in the late 70’s. By 1982 GM was converting most of their powertrains to use this type of system, and was the mainstay of the GM fleet until 1995. TBI’s use either 1, 2, or 4 fuel injectors and inject metered fuel directly on top of throttle plates much the same as a carburetor. The TBI unit is centrally located on an intake manifold that distributes an air/fuel mixture to each cylinder. GM & Chrysler systems used a low fuel pressure of about 12 psi. Ford used
