I have a 1988 Ford Thunderbird V8 - 2 days ago my batt was drained -
wouldn't hold charge bought new one - No issues until tonight when I tried
starting and batt was drained - Jumpped it and ran for 5 minutes, shutdown,
restarted fine so batt is charging, ran it for another 5 min and shutdown,
disconnecting batt till I can t/s tomorrow. Okay questions - I noticed the
day before my batt died the blinkers wouldn't come on all the time which
prior never had an issue with - Take note I packed my trunk up full so
stuff was pressing against the wires - Could there be a short somewhere in
the trunk to cause this??? The Alt, is it possible it is weak and will
discharge my batt over a period of time??? I plan to read out wires, check
my fuses - Any other pointers before I take the step of replacing my ALT.
Can the Alt be bad and still charge batt when driving??? Is it bad to
disconnect the batt each time I turn off the vehicle, in case I can find
the source over the weekend - Any help would be appreciated, can't afford
to take it to a shop and I'd rather do it myself, if I can just go through
the hassle of disconnecting the batt each time I shutdown w/o complications
I'll do so till I can fix it - Inputs Plz
You can do that... the only effect is that the ECM loses all it's learned
about running the engine at its most efficient.
Have the alt tested... you dont say whether the car has a voltmeter on
the dash, I thought they did.
The drain problem MAY be somewhere else.
So maybe you should go to radio shack and buy a cheap vom while you're at
Yeh, I'm a Krusty old Geezer, staving off dementia here..DEAL with it!
I will have access to a fluke multimeter over the weekend, hopefully I can
find the problem. I'll get the alternator tested in the AM - So your
saying it can drain my batt even if it seems to be working and charging
the Batt??? - Hopefully it can be as simple as an alternator however I
suspect something may be shorted in my trunk, since I was moving stuff and
packing it, turn signals working intermittingly - I'll look there too
Ok guys this is where I am at and I am leading to bad alt - Thsi what I get
from what I've read out
Engine Off- 11.97 Vdc
Engine Idle - 12.03 Vdc
Engine @ 2200 RPM - 12.37
Engine Idle w/ Lts On - 11.74 Vdc
Engine @ 2200 RPM w/ Lts on - 11.88 Vdc
Neg Batt Term Wire - .1 Ohms
Pos Batt Term Wile - .6 Ohms
Okay the Three wires going into the Alt on upper left side. Wires are old
so I can confirm the wire color but here is the resistance of each
Top Wire to Grd - 298 Ohms
Mid Wire to Grd - .4 Ohms
Bot Wire To Grd - .4 Ohms
Okay now who can help here, What I can see and please correct me if I am
wrong is that my alernator is weak to charge - Isn't the Batt suppose to
read around 13.5 to 14 Vdc while running esp. at 2200 RPM. I am guess
since one of the phases into the alternator is High resistance it has lost
a phase and isn't effectivly charging my Batt and maybe even draining my
Batt because of it. Anyways does my troubleshooting sound correct, anyone
know the resistance values of each phase in the alternator - Before I
begin ripping out my alternator please give me your thoughts on it.
Thanks for the help everyone,
It's most likely the alternator (diode). An alternator has three different
windings, and it sounds as if you've lost one. A healthy alternator will output
13.5 to 15.0 volts (15V BRIEFLY), depending on RPM, temperature, and state of
battery charge. A fully charged battery with no draw on it = 12.66 volts, and
the charging device has to input at least 1/2 volt MORE than that to overcome
internal resistances in wiring and the battery itself. In other words, 13.1
volts isn't charging the battery, but 13.3 volts is charging (VERY slowly).
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