At 11:07 PM 12/6/2010, Larry Alofs wrote:
>David,
>    Please clarify.  Are you saying that the mechanical inertia of the
>vane is a good or a bad thing  Do you feel that the programming of the
>ECU takes this inertia into account?

I'm saying it's a good thing and corresponds to the accelerator pump
in a carburetor.  When you open the throttle quickly, the air flow
increases very rapidly and the inertia of the vane, which is fairly
substantial, causes it to overswing somewhat.  This tells the ECU
that there's more air going through the system than actually is,
causing it to inject extra fuel, hence for that short interval a
richer mixture.

Since it's the AFM doing this and not the ECU, a MAF device would
need to simulate the effect in some way, by monitoring rate-of-change
of the airflow and increasing the signal to the ECU when there's a
rapid increase in flow.

Yrs,
d