You need the battery charged, and hooked up, to get a one
wire alternator to function.
To test:
A. Engine off. Measure the battery voltage.
B. Engine running, rev at least 3000 rpm. Measure battery voltage.
C. Engine running, rev the same. Turn on the lights. Measure
voltage.
Usually at A: 13.2V
B 14.2V (about a volt higher)
C 13.7V (some of a drop, but still charging).
Some of the "single wire" alternators need to hit something
like 4,000 rpm before the alternator will start charging.
Once it is "on" they work fine at lower rpms.
I've also come across some "single wire" alternators that
should have a "sense" wire hooked up from the battery
stud to the "sense" terminal.
Some "single wire" alternators are really internally
regulated alternators that need two additional wires
attached. "Sense" (from the battery) and "on" from the
ignition switch through a current limiting wire or bulb!
Sigh, lots of variations on the "single wire" alternators.
Any chance their is any documentation from the PO?
Can you take a photo of the alternator... look for the
two small spade connectors? Are they there?
Uh, did I mention there is more than one way "single wire
alternators" might be hooked up?
Cheers,
Tom
SPYDER62@aol.com wrote:
> Hi All
> The PO of my car did a GM one wire conversion, and last night after driving
> home, went out to move the car into the shop and it had a dead battery. The
> Headlights never have been bright even when battery shows 13 volts, so drive
> day time only, Just went out and tried to check the Alternator and it looks
>like
> it's only putting out 4 volts at rev's. I did energize it then took the wire
> off the battery post, is there a better way?
> thanks
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