Lets talk about voltage.

[roccit_53 at scirocco.cs.uoguelph.ca (C Boyko)]

Okay, I'm still screwing around with this same thing, BUT, if mine falls
below 12V, the fuel pump goes out/car dies. I've done wires to death, and
it only ever charges at 12.3 or so, and accessories knock it down to where
I can kill the car by turning them on. It'll run fine without accessories
on, and it starts really well. I'm buying an alternator aren't I?? And
where's a good place to get one? I keep hearing myths of cheap Bosch ones
at Canadian Tire, they want $279, since I won't have a core. That doesn't
seem that cheap to me.

Also, the fuel pump seems noisier when the voltage dips. Is this a case of
"bad fuel pump causes the draw", or "fuel pump gets noisy when it doesn't
have enough juice". The car seems to accelerate smoothly enough, it just
dies at idle with a ton of accessories running.

I just want to be triple sure before I beat a perfectly good alternator to
death, it's not going to come off gracefully. Advice appreciated.
cathy


On 6:09:23 pm 11/07/05 Chris Bennett <scirocco16vr32@gmail.com> wrote:
> I would suspect a loose connection to the voltmeter.  I would get a
> multimeter and check voltage across the battery before I made a call
> on that.  You should see 12-14 volts if your alternator is charging
> properly.  Turn off all the electrical stuff you can and see what it
> shows.
>
> In the alternator there is a diode bridge rectifier... these usually
> work or they don't... not much in between.  I think if you lose one
> diode it actually knocks two out of service and you get half as many
> pulses (and it doesn't look like DC anymore.)  Not sure if this will
> roughly half voltage or current.  I am thinking current.  Also with
> the windings... they mostly work or don't.  (from my
> experience...Please correct me if I am wrong.)
>
> Point is if you have 14 volts give or take one, then I would look for
> loose connections, corroded connections and/or grounds.
>
> Remember Ohms Law.
>
> HTH
> Chris
>
> On 11/7/05, Greg Pallett <greg.rocco@gmail.com> wrote:
> >  So after asking about 90a alternators, and not having come to any
> >  decision about that, I've been watching my volts gauge closely. I
> >  don't think I like what I see. In normal traffic I'm showing 12
> >  volts. Last winter, after Roger relayed my headlights, it was more
> >  like 12+, but I don't remember how much over. Last night, running
> >  just headlights (no fogs) and radiator fan, I was showing 11. THis
> >  morning on the drive to work, I was showing 12 and was comfortable
> >  with that. This afternoon, stuck in early rush hour traffic, with
> >  the radio OFF and the only load being the radiator fan I was
> > showing 11.5 or slightly less. I fear that in the dark of winter with
> >  highbeams and a heater fan on it may be too much draw. As I
> >  mentioned, I think last winter I had more volts to play with, but
> >  I don't remember any numbers. Could this be a sign of an
> > > alternator starting to get old? Yes, I know I sholuld/need to
> >  check all my grounds, perhaps even add a fancy grounding kit?
> >   Again, educate this fool.
> >   TIA
> >   Greg
> >
> >  --
> >  Aronsons First Law
> >  People who do crazy things are not necessarily crazy
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