It's me again with my alternator woes.
As you mayt recall, I have a Delco-Remy in my 1972 TR6. It's been going full
on and showing 17+ volts at idle and worse at higher revs unless I put on the
headlights.
I took it to the rebuilders today and they did what appeared to be a beautiful
job of blasting the outsides and rebuilding the insides. Other than the
bearing cap, one would swear it was a new unit.
I plugged everything back in and the same symptoms occurred. After a could of
starts she was toast. I think in my rapid testing of many options I managed to
start her with the main plug on the alternator unplugged. Bye bye diode pack.
Sigh...
So I have been over the wiring from one end to the other. Every blasted
switch, feature, unit etc. All work perfectly. (I've spent a fair old bit of
time cleaning up weirdness in the harness this year.)
The battery connection is at battery voltage when ignition is off. The
indicator wire is 0V at ignition off and about 0.4v lower with ignition on
(when disconnected. If I ground the indicator wire, the dash light
illuminates).
I redid all the alternator connectors that were definitely not good as only
about 20% of the copper filaments in the big Brown/White cable were actually
spotwelded to the copper connector.
So now I have nothing coming out. The indicator tab on the alternator seems to
go to about 12.0 v when the unit is turning so the indicator doesn't light as
it should since that tab should be pulled to ground until the unit fires up.
When the alternator was doing full on, you could hear a whine and the ammeter
was showing high charge since it was overdriving the battery. The alternator
was getting very warm fast and not from thermal conduction from the engine.
I've checked and checked, I just can't find an obvious wiring fault.
Can anybody conceive of a wiring fault that could cause this weird situation?
Is there a short in the armature that would cause a normal alternator
rebuilding shop to mis-diagnose a repair for a short time. It seemed that the
unit was working for a short time (30 seconds) albiet with the same twitchy
ammeter reading before it went full on. It may well have been a wiring fault
that killed it, but I'm damned if I can find the problem.
Back to the alternator shop in the morning for what will be an undoubted blame
session. I just want my car back on the road.
Cheers,
Mark
1972 TR6 (battery powered)
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