Throttle Body Injection (TBI) Unit
The TBI unit is made up of 2 assemblies, throttle body and fuel body. Throttle body consists of an Idle Air Control (IAC) valve (which controls air flow) and a throttle position sensor. Fuel body consists of a fuel meter cover, a built in pressure regulator and 2 fuel injectors that supply fuel to engine.
The throttle body portion of TBI unit may contain ports located at above or below throttle valve. These ports create vacuum signals for EGR valve, MAP sensor and canister purge system.