Re: turbo seca - maf>turbo

["Bruce Plecan" <nacelp@bright.net>]

??
Guestion was how do they know the wire's temp?.

By having a target voltage drop across the hot wire, and then knowing how
much current it takes to keep that VD, you know how much of a "chilling"
effect the air passing it has, and hence it's mass.
  That's what I've heard.   GM has been known to tell a story about how
things work to make it eas to present to mechanics, and hence I use words,
that reflect that I don't know the info from first hand experience.
Grumpy



> << I'd imagine the element has similiar properties to a thermistor, and
just
>  knowing the voltage drop across it would allow you to figure it's
>  resistance, and hence temperature.
>  Grumpy >>

> Thats how a hot wire MAF works. By measureing the current needed to obtain
> the wires temp ,  it measures the air flowing (cooling off) the wire.
Hence a
> "hot wire MAF" Remember the old vettes/Camaros etc had a "burn off relay"
> which overheated the wire at key on to clean the wire. I imagine that
being
> the case, that the circuit is pretty sensative to contaminants. matter of
> fact, there is a TSB out on Fords and Mazda's using the hot wire sensor
that
> MAF too high codes along with O2 reaching rich limit is usually caused by
> contaminants on the wire. Just FWIW. Must be pretty sernsative.
> Jim Testa                                                         TType86
on


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