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full thottle switch

Subject: full thottle switch
From: treed2 at u.washington.edu (T. Reed)
Date: Fri Sep 19 20:59:26 2003
In-reply-to: <001101c37f18$31acd9a0$8c00a8c0@wubba>
References: <IMEIILEDMBCOMEJNDNBICEGEEBAA.txrocco@sbcglobal.net><Pine.A41.4.58.0309191210290.101182@dante53.u.washington.edu><002901c37f05$a4377dd0$972e3542@phattydopebox><Pine.A41.4.58.0309191723580.105890@dante10.u.washington.edu><001101c37f18$31acd9a0$8c00a8c0@wubba>

Robert,

First of all, you say "Larry is right shorting something means connecting
it to ground" but nowhere did Larry say this. His message said something
to the effect of "a voltmeter causes a short, not an ammeter", which is
incorrect.

Second, shorting something does NOT imply connecting it to ground. That is
a "short circuit to ground". Throughout all of my electrical engineering
courses the instructors have referred to "shorts" or "short circuits"
as the direct connection of any two wires (presumably without a load)
between which there is a voltage potential. +12v and ground are just one
possibility. If you want to be more exact about it, the name "short"
comes from the fact that you are running a wire with essentially zero
resistance in parallel with a circuit, thereby shunting all of the current
through the wire and bypassing the circuit. Nothing about this suggests
that one side of the wire must be connected to ground.

In any case, if the input to the injection computer is expecting a
resistance and it sees none because an ammeter is connected across the
input terminals, things can (and will) fry inside.

It's scary just how much misinformation people are willing to circulate on
this list with the conviction that they are right. If you are unsure about
something it doesn't take much more than saying "I think" to give the
person who asked the question at least a suggestion to double check what
you say before they go out and destroy their equipment.

My 2 cents..

-Toby

On Fri, 19 Sep 2003, Robert Piwonka wrote:

> well no, technically Larry is right shorting something means connecting it
> to ground.  So yep that's what you do with a voltmeter, put in parallel and
> series for ammeter.  The rest of your explanation is the correct metaphor.
>
> Robert Piwonka
> ----- Original Message -----
 > From: "T. Reed" <treed2@u.washington.edu>
> To: "L F" <rocco16v@netzero.net>
> Cc: <scirocco-l@scirocco.org>; "ATS - Patrick Bureau"
> <txrocco@sbcglobal.net>
> Sent: Friday, September 19, 2003 7:27 PM
> Subject: Re: full thottle switch
>
>
> > Umm, no...
> >
> > A voltmeter measures voltage, which is like pressure in a pipe. In order
> > to do this it just "attaches to a fitting" on the circuit.
> >
> > A ammeter measures current, which is like flow through a pipe. In order to
> > do so it has to lie in line with the pipe (like a valve).
> >
> > And, just like a valve or a "flow meter", it behaves to the rest of the
> > circuit as a normal piece of pipe, but with measuring capabilities.
> > A short circuit (but with measuring capabilities, heh!).
> >
> > If you need a better explanation please say so.
> >
> > But trust me, I've seen more than enough people blow the fuse in their
> > multimeter by hooking it up to a circuit as if it were a voltmeter.
> >
> > -Toby
> >
> > On Fri, 19 Sep 2003, L F wrote:
> >
> > > Nope.
> > >   Substitute 'voltmeter' for ammeter....
> > >
> > > Larry
> > >   ----- Original Message -----
> > >   From: T. Reed
> > >   To: ATS - Patrick Bureau
> > >   Cc: scirocco-l@scirocco.org
> > >   Sent: Friday, September 19, 2003 12:11 PM
> > >   Subject: RE: full thottle switch
> > >
> > >
> > >   Uh... that's not good!
> > >
> > >   You ought to try to remember that whenever you connect an ammeter to
> > >   something you are shorting it out!
> > >
> > >   -Toby
> > >
> > >   On Thu, 18 Sep 2003, ATS - Patrick Bureau wrote:
> > >
> > >   > my setup is CIS with knock box 2L 8v.
> > >   >
> > >   > I tried to get mA from the testing plug (near brake booster) but I
> can
> > >   > onlyget mVolts from it.
> > >   >
> > >   >
> > >   > ATS - Patrick Bureau - txrocco@sbcglobal.net
> > >   > ----------------------------------------------
> > >   > MSN:ATSGTX@hotmail.com |YAHOO:ATSGTX@yahoo.com
> > >   > ICQ:32918816           |AIM:Texasscirocco
> > >   > ----------------------------------------------
> > >   >
> > >   >
> > >   > =>-----Original Message-----
> > >   > =>From: scirocco-l-bounces@scirocco.org
> > >   > =>[mailto:scirocco-l-bounces@scirocco.org]On Behalf Of Dan Bubb
> > >   > =>Sent: Thursday, September 18, 2003 11:08 AM
> > >   > =>To: Rhett Farnum; t.piwonka@ttu.edu; scirocco-l@scirocco.org
> > >   > =>Subject: Re: full thottle switch
> > >   > =>
> > >   > =>
> > >   > =>Got me!
> > >   > =>They may have a ground or power wire in common, but that's all.
> > >   > =>Maybe somebody rewired your car?
> > >   > =>Using the cold start injector to provide additional fuel has been
> > >   > =>hashed out
> > >   > =>endlessly by everybody thinking they need more fuel, but it's a
> crummy
> > >   > =>solution because 1) the distribution between cylinders sucks 2)
> > >   > =>there is no
> > >   > =>control over the quantity of fuel injected, it's either off or on.
> > >   > =>Doesn't keep people from trying it.
> > >   > =>If your WOT switch does activate your cold start injector you
> might think
> > >   > =>about rewiring back to the original schematic cause it would
> certainly be
> > >   > =>injecting more fuel than your engine needs.
> > >   > =>Dan
> > >   > =>
> > >   > =>
> > >   > =>> If it doesn't use the cold start injector why is my switch
> > >   > =>wired to it???
> > >   > =>>
> > >   > =>>
> > >   > =>>
> > >   > =>> Peace Out,
> > >   > =>> Rhett
> > >   > =>> Rocco_crossing
> > >   > =>> '83 Rocco (autocross ready, tune up, install harness, and
> finally I may
> > >   > =>get
> > >   > =>> to makeing it look better!!)
> > >   > =>>
> > >   > =>>
> > >   > =>>
> > >   > =>>
> > >   > =>>
> > >   > =>> >From: "Dan Bubb" <jdbubb@ix.netcom.com>
> > >   > =>> >To: "Rhett Farnum" <rocco_crossing@hotmail.com>,
> <t.piwonka@ttu.edu>,
> > >   > =>> >  <scirocco-l@scirocco.org>
> > >   > =>> >Subject: Re: full thottle switch
> > >   > =>> >Date: Thu, 18 Sep 2003 08:01:34 -0400
> > >   > =>> >
> > >   > =>> >It does not use the cold start injector!
> > >   > =>> >The cold start injector is used only when the engine is
> > >   > =>cranking (and not
> > >   > =>> >always then) and no other time.
> > >   > =>> >
> > >   > =>> >The full throttle switch increases DPR current on CIS-E (16V),
> which
> > >   > =>> >increases fuel flow through the normal injectors.
> > >   > =>> >On CIS-lambda (8V) it increases the duty cycle of the frequency
> valve
> > >   > =>again
> > >   > =>> >increasing fuel flow through the normal injectors.
> > >   > =>> >
> > >   > =>> >On CIS-lambda closing the switch almost always increases
> > >   > =>engine speed and
> > >   > =>> >smoothes out the idle (especially if you have a big cam)
> because the
> > >   > =>engine
> > >   > =>> >goes open loop (stops looking at O2 sensor output) and richens
> the
> > >   > =>mixture
> > >   > =>> >and most engines like to idle richer than stochiometric.
> > >   > =>> >NOTE: I guess this assumes your car is correctly tuned and FV
> > >   > =>duty cycle
> > >   > =>> >oscillates around 50% at idle.
> > >   > =>> >
> > >   > =>> >On CIS-E closing the switch again causes the engine to go open
> > >   > =>loop. DPR
> > >   > =>> >current is supposed to go to 16mA if engine speed is over 2500
> > >   > =>RPM. On my
> > >   > =>> >car DPR current goes to a steady 8mA with the car idling. I'm
> not
> > >   > =>> >absolutely
> > >   > =>> >sure how the engine will respond by closing the switch at idle.
> I would
> > >   > =>> >assume if the mixture is set at 10mA (Bentley recommended
> setting) then
> > >   > =>if
> > >   > =>> >it goes to 8mA by pressing the switch the engine will lean out
> a little
> > >   > =>and
> > >   > =>> >drop a few RPM. In any event I don't think it will make a huge
> > >   > =>difference
> > >   > =>> >as
> > >   > =>> >long as your mixture is tuned correctly.
> > >   > =>> >Dan
> > >   > =>> >
> > >   > =>> >
> > >   > =>> > > It uses the cold start injector. If you ahve voltage that
> means you
> > >   > =>> >injector
> > >   > =>> > > is either shot or clogged. Try fom fuel inj. cleaner and if
> that
> > >   > =>doesn't
> > >   > =>> > > work replace. ~$5 at a bone yrd.
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > > Peace Out,
> > >   > =>> > > Rhett
> > >   > =>> > > Rocco_crossing
> > >   > =>> > > '83 Rocco (autocross ready, tune up, install harness, and
> finally I
> > >   > =>may
> > >   > =>> >get
> > >   > =>> > > to makeing it look better!!)
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > >
> > >   > =>> > > >From: "Robert Piwonka" <t.piwonka@ttu.edu>
> > >   > =>> > > >To: "scirocco" <scirocco-l@scirocco.org>
> > >   > =>> > > >Subject: full thottle switch
> > >   > =>> > > >Date: Thu, 18 Sep 2003 00:48:07 -0500
> > >   > =>> > > >
> > >   > =>> > > >When I press the full throttle switch at idle should the
> car bog
> > >   > =>down?
> > >   > =>> > > >Cause it doesn't.  However I tested the voltage on the
> output and I
> > >   > =>> >gets
> > >   > =>> > > >12v
> > >   > =>> > > >when activated and not 12v when not, so it appears to be
> working.
> > >   > =>> > > >
> > >   > =>> > > >Also how does the full throttle switch richen the mixture?
> Does it
> > >   > =>> >change
> > >   > =>> > > >the dpr current or use the cold start injector or what?
> > >   > =>> > > >
> > >   > =>> > > >Thanks
> > >   > =>> > > >Robert Piwonka
> > >   > =>> > > >
> > >   > =>> > > >
> > >   > =>> > > >_______________________________________________
> > >   > =>> > > >Scirocco-l mailing list
> > >   > =>> > > >Scirocco-l@scirocco.org
> > >   > =>> > > >http://neubayern.net/mailman/listinfo/scirocco-l
> > >   > =>> > >
> > >   > =>> > >
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Follow-Ups:
- multimeter vows and electrical issues RE: full throttle switch
  - From: txrocco at sbcglobal.net (ATS - Patrick Bureau)
- full thottle switch
  - From: rocco16v at netzero.net (L F)
- full thottle switch
  - From: t.piwonka at ttu.edu (Robert Piwonka)
- full thottle switch
  - From: t.piwonka at ttu.edu (Robert Piwonka)

References:
- full thottle switch
  - From: txrocco at sbcglobal.net (ATS - Patrick Bureau)
- full thottle switch
  - From: treed2 at u.washington.edu (T. Reed)
- full thottle switch
  - From: rocco16v at netzero.net (L F)
- full thottle switch
  - From: treed2 at u.washington.edu (T. Reed)

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