[alfa] Alternator explanation needed..

["Brian Shorey" <bshorey@xxxxxxxxx>]

Hey folks,

I'm trying to help a friend get a car running for the convention, and I need
an explanation of how an alternator works..  We're wasting too much time
staring at wiring, and not making fast enough progress.

We finally got the car running today, but when trying to determine if the
alternator is charging we came across some puzzling data.  First, an
explanation of what we're working with, then the data we're observing.

The car is a late 60's Giulia Super.  The dash and gauges are a hybrid of
stock and aftermarket (stock gauges, aftermarket ignition switch).  The
engine is a Spica injected 2 liter.  There is no wiring harness (we're
making it up as we go), and the fuse box is some aftermarket thing.

To confuse things even more, we didn't have an external voltage regulator,
so we tossed the alternator that came with the 2 liter and bolted up a
Milano alternator.

The Milano alternator has one stud, to which we connect to the hot lead on
the solenoid.  Then it has only one other lead, to which we run a green wire
to ???

It looks like the green wire should be connected to an alternator warning
lamp.  Ok..

If we don't connect the green wire to anything, the car starts and runs
fine, and stops when we turn off the ignition switch.  However, to test the
alternator, I tried disconnecting the battery with the car running and it
stalled immediately.

However, if I apply 12v to that green wire, the car will run with the
battery disconnected.  BUT, if I turn off the ignition, it won't stop
running until I disconnect the green wire.

I'm not sure I understand how this should be working, what I need to connect
it to, etc.  The best I can see is on a wiring diagram for a late 70's Spica
Spider, which shows the green lead connected to the alternator warning lamp,
and the other side of the lamp connected to a switched ignition lead?

Thanks in advance for any insight anybody can provide.

bs
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