Here is the internal circuit diagram for the AFM...
![Image](https://i.imgur.com/uY3445X.png)
The basic function of the AFM is to tell the ECU how much air is entering
the angine by monitoring how far the flap opens. When the flap opens it
moves a slider over a carbon track creating a variable voltage input for
the ECU. This signal is used by the ECU to control the fuel injector timing.
There are two other functions built into the AFM. The first is the THA or
inlet air temperature sensor and the second is the FC aka IDL or fuel control
switch. The FC switch contacts are closed when the flap opens due to the
air drawn in when the engine is cranking. This creates a ground path that
allows current to flow thru the COR which in turn sends power to the fuel
pump. As long as the flap stays open, the fuel pump will get power.
If the FC switch does not close or if the ground path from the AFM to the
chassis is broken, the engine will not receive fuel once you let go of the
key, and the engine will die. The cold start injector circuit is independent
of the ECU and the cold start injector will squirt only while the engine is
cranking. The engine will fire for a couple of seconds and then die if the
FC has not supplied a ground for the COR.
Cheers... jondee86