8V92 alternator questions

[Leroy Eckert]

Don:
It does sound like alternator problems. Many times alternator problems are not
the alternators fault. I may get beat to death on this but I would first check
the ground strap from the frame to the engine and the ground connection at the
point where the battery ground connects to the frame. If there is not integrety
in both areas you will have strange problems. I know you changed the batteries,
but I wonder if you have a floating ground? Weird stuff is going on. It has
been three years since I messed with mine , but I believe the alternator ground
wire connects to a bolt on the top of my engine. If the engine is not properly
grounded and the alternator is grounded to the engine, it will not work properly
and can also be a factor in alternator failure. Just a thought, and it will
not take much to check it out. If it is the problem, then it saved you a lot of
work and time. Happy your trip was a safe one.

Leroy Eckert
1990 WB-40"Smoke N Mirrors"
Niceville, FL



----- Original Message -----
From: Don Bradner
To: WanderlodgeForum@yahoogroups.com
Sent: Wednesday, February 21, 2007 10:07 PM
Subject: [WanderlodgeForum] Re: 8V92 alternator questions


I am home now, and will hopefully have a couple of months to get things ready
for the next trip. I had an "interesting" day, and will outline it while the
data is fresh in my mind.

We started the day in sporadic rain, that progressed to steady rain. Early on,
when I would turn on my headlights, the transmiission would flash "Do not shift"
and "Check transmission", 3 blinks, then off, then repeat in a few seconds. That
would end with turning the headlights off.

Later in the day, when the headlights were on all the time, the transmission
did not complain.

With headlights off, I had voltage readings typically like:

Analog gauge, 13.2 volts
Prosine 2000 monitor, 13.4 volts drawing 8-10 amps
Digital readout from the engine computer, regular jumping around between 12.0
and 13.2, most around 12.5 and 12.7 (via VMSpc interface)
Alternator 1 zero output, Alternator 2, 25 amps

With headlights on, after being on some time:

Analog gauge, 12.5 volts
Prosine 2000 monitor, 13.0-13.2 volts drawing 8-10 amps
Digital readout, regular jumping between 12.0 and 12.5, most around 12.0,
12.1, and 12.3. Occasional 11.8
Alternator 1 zero output, Alternator 2, 50 amps

Still with headlights on, generator running:

Analog gauge, 13.2 volts
Prosine 2000 monitor, 13.9 volts charging at 25-30 amps
Digital readout, regular jumping between 12.5 and 13.2, most around 12.7
Alternator 1 zero output, Alternator 2, 25 amps

Conclusion: One alternator is not working, and the other is "weak." Hard to
say yet if the problems are with the alternators themselves, or with connections
to them. That will be part of the projects I have to work on when it dries a bit
(rain predicted for every day in the next week).

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA





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