Throttle Body position sensor

[Project_E30]

This question is about the throttle body position sensor.

I have just set one up so that the micro switch clicks as soon as the throttle is opened. However in a total BMW mag it says about a resistance change at the half way position between Zero and Full throttle.

However the sensor I have only senses whether it is at idle, then off idle and finally full throttle.

My question is:
Do I have an old position sensor?

Or is the Mag wrong and does the ECU get the throttle reading from elseware? (How does the engine know whether I want 1/4 throttle or 1/2 etc)


Cheers

[Simon]

The airlfow meter senses the amount of air being taken in to the engine, so this tells the ecu how much throttle is applied...

...the TPS (throttle position sensor) should sense idle, just of idle (should hear a click) and then full throttle, but you won't hear a click at full throttle.

[Project_E30]

Cheers that all I needed to confirm.