Vane Air Flow Meter

17th June 2003 Midnight (I can't sleep thinking of AFM)

AFM Breakdown

The basics will not be discussed. Please read from

Fuel Pump Engage Pin - There are two metal needle, which upon contact switches off the fuel pump. The idea is when the car meets an accident and stops, the engine will stop and hence the air flow stops and hence the flap will fully close and hence the needle will touch and hence trigger the fuel pump relay to disengage. For safety reasons.

This method also ensures that the fuel pump does not engage during key-ON. It saves battery power and make sure no extra fuel is being pressurise when not in use.

Please notice the orange arrows array. They show the AFM's reader needle trail. From the beginning (Flap closed) to the end (Flap fully open). One can see the pressure mark left by the reader needle. The more open it is, the less pressure. In fact a whole section near the end does not have any mark.

In a way it shows how often the AFM visited fully open compared to partial open. One may also argue due to it's compulsory passage travel it is only natural to leave marks like this. But if......

The air intake temperature sensor is no more than a (Thermo-resistor), which does not damage naturally. It's resistance changes over varying temperature.


  1. AFM Breakdown
  2. Dismemberment
  3. Flap Tension
  4. Engine Warning Light On
  5. Warning / Tips - Buy Vane Air Flow Meter (AFM)



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