Vacuum is a difference of potential,like voltage. When
you draw really heavily from a battery,current is
maximum,but voltage decreases some. At wide open
throttle,there's almost no restriction at the throttle
body so the flow is very high (low vacuum). Since a
clogged cat increases restriction,it's the opposite.
At least this is my take on it. (Ask Bernd.) :)
Thanks!
Steve P.
--- Jamie Calder <jcalder3@cfl.rr.com> wrote:
>
> Me too...It would seem to me that a clogged cat
> would create more pressure
> (back pressure) and not vacuum. I realize this
> isn't so...but why? How
> about Vacuum 101, The Why's and Why Not's.
>
> Thanks,
> James
>
> -----Original Message-----
> From: owner-dakota-truck@bent.twistedbits.net
> [mailto:owner-dakota-truck@bent.twistedbits.net] On
> Behalf Of Rick Barnes
> Sent: Saturday, September 22, 2007 5:39 PM
> To: dakota-truck@dakota-truck.net
> Subject: RE: DML: RE: MAP sensor
>
>
> I am so clueless about vacuum...unless it's a Hoover
>
> Rascal
>
> -----Original Message-----
> From: owner-dakota-truck@bent.twistedbits.net
> [mailto:owner-dakota-truck@bent.twistedbits.net] On
> Behalf Of
> bernd@dodgetrucks.org
> Sent: Saturday, September 22, 2007 3:31 PM
> To: dakota-truck@dakota-truck.net
> Subject: Re: DML: RE: MAP sensor
>
>
> Clogged cat makes the vacuum go up, not down.
>
> - Bernd
>
> >
> > Clogged cat?
> >
> > Rascal
> >
> > -----Original Message-----
> > From: owner-dakota-truck@bent.twistedbits.net
> > [mailto:owner-dakota-truck@bent.twistedbits.net]
> On Behalf Of Steve
> > Preston
> > Sent: Saturday, September 22, 2007 12:35 PM
> > To: dakota-truck@dakota-truck.net
> > Subject: DML: MAP sensor
> >
> >
> > Well,I finally bought a vacuum gauge,and checked
> my work truck with
> > it. Judging from actual vacuum,it's all right.
> Runs at 18-19 in HG at
> > idle,jumps to zero when I snap the throttle,climbs
> to a little over
> > the idle reading,then settles back to the original
> reading. However,my
> > MAP sensor doesn't read close to this at all. It
> stays at about 9-10
> > in HG. Bad sensor,right?
> >
> > History lesson: 2003 Dak 3.9 CC 2WD V6 with
> 42RE,intermittent missing
> > and bad power loss while driving. TPS ok,new plugs
> and wires,dist.cap
> > ok,fuel pressure and all injectors ok.
> >
> > Thanks!
> >
> > Steve P.
> >
> >
> >
> >
>
____________________________________________________________________________
> > ________
> > Don't let your dream ride pass you by. Make it a
> reality with Yahoo!
> > Autos.
> > http://autos.yahoo.com/index.html
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
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This archive was generated by hypermail 2b29 : Tue Oct 02 2007 - 15:23:18 EDT