jon@dakota-truck.net wrote:
> Terrible Tom <silvereightynine@aol.com> wrote:
>
>>Refresh my memory here... the higher the number value that the MAP
>>reports - the more vacuum? And the lower the value - the closer the
>>manifold is to external air pressure levels? (meaning less negative vacuum)
>
>
>>Right?
>
>
>
> Its the opposite - the higher the number reported by the MAP, the
> less the vacuum. Remember, the MAP is a pressure sensor and is
> reading pressure. The higher the number, the higher the pressure.
> The vacuum will be inversely proportional to the pressure, so the
> higher the MAP reading, the lower the vacuum (i.e. the vacuum is
> moving towards zero), and the lower the MAP reading, the higher the
> vacuum (the vacuum is moving away from zero).
>
> This is why, when the engine isn't running, the MAP will report
> something like 29"; that is the barometric pressure. When the engine
> starts and a vacuum is created inside the intake manifold, the MAP
> reading goes down because the engine vacuum is offsetting some of the
> ambient barometric pressure.
>
<Joilet Jake> I SEEE THE LIIIIGHT!!!!! </Joilet Jake>
Ok then... for the sake of sanity here - lets define some terms...
"less vacuum" = meaning higher actual barometric PRESSURE - less suction
effect - leaf blower stuff!!
"more vacuum" = lower actual barometric pressure - negative pressure -
suction!! Hoover vac on high stuff!!
as wild as this seems - I see what Bernd is getting to... my MAP sensor
is reporting MORE vacuum on *acceleration* under some circumstances...
but not all - most of the time it looks like the MAP is reporting
correctly it seems.
This is what you (Bernd) are saying happens with a clogged CAT?
Very friggin weird...
-- ------------------------------------------------------------ 50 seconds of pleasure, 50 years of regret... Wookiee Love is pointless - Anarchy Steering Committee ------------------------------------------------------------ http://members.aol.com/silvereightynine/ AIM & Yahoo: SilverEightynine ------------------------------------------------------------
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