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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / December 2007

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1990 Lebaron 3.0, problem with charging circuit

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JustMe - 24 Dec 2007 01:13 GMT
drained one battery already. Installed a new one, but am only reading
11.8 volts while car is running (12.2 while car is off). There's about
60 milliamps of drain between negative cable and negative battery
terminal (obviously while car is off). I think this is normal, but
regardless this isn't the problem. I imagine it could just be the
alternator. I had a problem like this some time ago, and it turned out
to be a fuse (some part of alternator circuit?). I checked every fuse,
even with a continuity tester, so unless the fuse box is messed up,
that isn't it.
About a week ago, I left the lights on for about an hour. It started
back up, and I raced it around town for ~1/2 hour to charge it back up
(bad idea? Should have just left it idling?). Don't know if that has
anything to do with it. Perhaps a little before that time, or after,
can't remember, the meter on the dash was reading a bit higher then
normal (I guess a volt or 2?). Prior thanks for any suggestions.
Scott Dorsey - 24 Dec 2007 13:28 GMT
>drained one battery already. Installed a new one, but am only reading
>11.8 volts while car is running (12.2 while car is off). There's about
>60 milliamps of drain between negative cable and negative battery
>terminal (obviously while car is off). I think this is normal, but
>regardless this isn't the problem. I imagine it could just be the
>alternator.

That would make sense.  60 mA is a lot of idle draw, but many cars are like
that now.

>I had a problem like this some time ago, and it turned out
>to be a fuse (some part of alternator circuit?). I checked every fuse,
>even with a continuity tester, so unless the fuse box is messed up,
>that isn't it.

There are fusible links all over the place.  Measure continuity between the
positive pole of the battery and the output of the alternator.  Make sure
the two are connected together and the fusible linke between them is not
open.  Make sure there is continuity between the alternator ground and
the battery ground; sometimes damaged ground straps cause weird problems.

> About a week ago, I left the lights on for about an hour. It started
>back up, and I raced it around town for ~1/2 hour to charge it back up
>(bad idea? Should have just left it idling?). Don't know if that has
>anything to do with it. Perhaps a little before that time, or after,
>can't remember, the meter on the dash was reading a bit higher then
>normal (I guess a volt or 2?). Prior thanks for any suggestions.

The voltmeter was reading _high_ but the battery is not charging?  What
is the voltage across the battery when the engine is running?  After you
drive around a little, is the idle voltage across the battery higher or
lower than when you started out?

You may also have an alternator that is producing too high a voltage
because of a regulator failure, and is damaging your battery.  The
meter will tell you.  The meter is your friend.
--scott
Signature

"C'est un Nagra.  C'est suisse, et tres, tres precis."

JustMe - 25 Dec 2007 01:51 GMT
> >drained one battery already. Installed a new one, but am only reading
> >11.8 volts while car is running (12.2 while car is off). There's about
[quoted text clipped - 28 lines]
> drive around a little, is the idle voltage across the battery higher or
> lower than when you started out?

I haven't driven it since I parked it. Battery read 12.2 while engine
off, 11.8 while idling. When I did drive the thing home the other day,
ANY accessory would cause the dash meter to dip - even putting the
radio on and turning up the volume enough.

Before the batteries starting giving out, yes the meter on the dash
was reading on the high side. Can these alternators be rebuilt (I know
that there are kits for other alternators for sure)? Do these things
have ball bearings or sleeves? The original alternator I still have,
too it off the last time I had this problem, and installed the
largeish one that came was in the trunk (came with the car). It's
bigger then the old one, but still fits. Been running with that one
since last march. Problem with the original is it seized up. I'd
probably want to replace electrical stuff in the larger one that's
currently on the car, because I don't know if I could *unseize* the
old one. Soldering and stuff is not a problem.

> You may also have an alternator that is producing too high a voltage
> because of a regulator failure, and is damaging your battery.  The
> meter will tell you.  The meter is your friend.

Right, so those part generally can be replaced (the ones internal to
the alternator)? This car is a darned good runner, but I really don't
even feel like putting in the price of a new/rebuilt unit if I can
help it.
Scott Dorsey - 25 Dec 2007 20:20 GMT
> I haven't driven it since I parked it. Battery read 12.2 while engine
>off, 11.8 while idling. When I did drive the thing home the other day,
>ANY accessory would cause the dash meter to dip - even putting the
>radio on and turning up the volume enough.

You'd said that, and that makes perfect sense if your alternator was
not functioning or no longer connected to the battery.

But then LATER you said that your dash meter was reading HIGH by a
couple volts.  Are both of these actually the case?

> Before the batteries starting giving out, yes the meter on the dash
>was reading on the high side. Can these alternators be rebuilt (I know
[quoted text clipped - 7 lines]
>currently on the car, because I don't know if I could *unseize* the
>old one. Soldering and stuff is not a problem.

Wait, wait.  The old alternator seized up, and you replaced it with
one that is a different size.  You didn't mention that at all.

Okay.... that sounds like your problem.  Where did you get this replacement
from?  Was it from a legitimate rebuilder or a cheesy chain store?

>> You may also have an alternator that is producing too high a voltage
>> because of a regulator failure, and is damaging your battery.  The
[quoted text clipped - 4 lines]
>even feel like putting in the price of a new/rebuilt unit if I can
>help it.

For the most part, it's so cheap to get a good rebuild done that it's not
worth your time to do it yourself.  Take the old one to a local starter
and alternator rebuilder and have them do the job.  It won't cost much.
They will replace all the bearings, the brushes, turn down the commutator,
inspect, measure, and load test everything without charging an arm and a
leg.
--scott

Signature

"C'est un Nagra.  C'est suisse, et tres, tres precis."

JustMe - 26 Dec 2007 14:33 GMT
> > I haven't driven it since I parked it. Battery read 12.2 while engine
> >off, 11.8 while idling. When I did drive the thing home the other day,
[quoted text clipped - 6 lines]
> But then LATER you said that your dash meter was reading HIGH by a
> couple volts.  Are both of these actually the case?

Let me start over. About the time I left the lights on and drained
the battery (a little before or since then, can't really remember) the
dash voltmeter was noticeably higher then normal. Then a week later I
guess the battery got drained (started it one morning and CE light was
on, subsequent starts were a little strained, then finally that
battery got too low to start engine). Replaced battery, drove it,
noticed meter was down sometimes at this point, about where it should
be at other points in the journey, but mostly down. Then measured
voltages with multimeter as reported.

> > Before the batteries starting giving out, yes the meter on the dash
> >was reading on the high side. Can these alternators be rebuilt (I know
[quoted text clipped - 13 lines]
> Okay.... that sounds like your problem.  Where did you get this replacement
> from?  Was it from a legitimate rebuilder or a cheesy chain store?

When I bought the car from my nephew, there were a bunch of parts in
the trunk. The current alternator is physically larger then the
original, but *fits*. So since this is a beafier unit, that's what's
causing the problems? I didn't think that would be the case. There are
different alternators for a single car, whether you have AC or not.
But we don't always run out AC's.

> >> You may also have an alternator that is producing too high a voltage
> >> because of a regulator failure, and is damaging your battery.  The
[quoted text clipped - 11 lines]
> inspect, measure, and load test everything without charging an arm and a
> leg.

Sure if that's the problem. No big deal, I'd buy another alternator.
I just don't want to find out that my battery still isn't being
charged. Thanks for the help by the way.
Scott Dorsey - 26 Dec 2007 14:57 GMT
>> > I haven't driven it since I parked it. Battery read 12.2 while engine
>> >off, 11.8 while idling. When I did drive the thing home the other day,
[quoted text clipped - 16 lines]
>be at other points in the journey, but mostly down. Then measured
>voltages with multimeter as reported.

Okay, and this is all with the new alternator, right?  The alternator
had been replaced before you got the car, you say?

>> Wait, wait.  The old alternator seized up, and you replaced it with
>> one that is a different size.  You didn't mention that at all.
[quoted text clipped - 8 lines]
>different alternators for a single car, whether you have AC or not.
>But we don't always run out AC's.

Where did this alternator come from?
Was it from a legitimate rebuilder or a cheesy chain store?

> Sure if that's the problem. No big deal, I'd buy another alternator.
>I just don't want to find out that my battery still isn't being
>charged. Thanks for the help by the way.

So, take the voltmeter and measure the voltage on the output terminals
of the alternator with the engine running.  If it's as low as the battery
voltage, the alternator is not functioning.

If the alternator is a cheap chain store rebuild, it's almost certainly
the problem.
--scott
Signature

"C'est un Nagra.  C'est suisse, et tres, tres precis."

JustMe - 26 Dec 2007 23:30 GMT
> Okay, and this is all with the new alternator, right?  The alternator
> had been replaced before you got the car, you say?

right. The *new* alternator that I found in the trunk. When I had a
similar problem with this car, I put the *new* one on, and that wasn't
the problem (it was the fuse).

> Where did this alternator come from?
> Was it from a legitimate rebuilder or a cheesy chain store?

Probably a cheesy chain store. Best guess. That would denote a cheesy
rebuilder (generally). Rebuilt ones from Carquest or Advance are about
140$, and there's a ~60$ core charge! It's why I asked about parts for
rebuilding one, but apparently no one carries them (and the regulator
may be in the computer also IIRC).

> So, take the voltmeter and measure the voltage on the output terminals
> of the alternator with the engine running.  If it's as low as the battery
> voltage, the alternator is not functioning.

Ok, will do. I'll probably also take it to the parts store to have
them test it.

Like I said, I still have the original alternator (right size too!)
but I left it outside and it won't spin. I sprayed it with PB, but
that might not do it. Worst comes to worst, I may try to dismantle it
and replace the bearing even (with a small harbor freight arbor
press?). Being that the thing seized, that seems to indicate to me
that there are ball bearings in there. I could probably also try to
install them by tapping with a socket in place. Don't know...
Don't really feel like dropping ~150$ into this old thing. Like I
said a great runner, but old is old...
Scott Dorsey - 27 Dec 2007 00:51 GMT
>> Okay, and this is all with the new alternator, right?  The alternator
>> had been replaced before you got the car, you say?
>
> right. The *new* alternator that I found in the trunk. When I had a
>similar problem with this car, I put the *new* one on, and that wasn't
>the problem (it was the fuse).

So, you bought this car, and it came with a spare alternator in the
trunk.... and before something failed and you put the spare alternator
on, but it turned out to be a failed fusible link.

Ohhh-kay.

>> Where did this alternator come from?
>> Was it from a legitimate rebuilder or a cheesy chain store?
[quoted text clipped - 4 lines]
>rebuilding one, but apparently no one carries them (and the regulator
>may be in the computer also IIRC).

The chain stores hardly ever carry rebuild kits, because they want
you to buy their crappy rebuild.  Stay away from Carquest and Advance
and take the alternator to a real alternator rebuilder.

>> So, take the voltmeter and measure the voltage on the output terminals
>> of the alternator with the engine running.  If it's as low as the battery
>> voltage, the alternator is not functioning.
>
> Ok, will do. I'll probably also take it to the parts store to have
>them test it.

What parts store?  Most of the chain stores aren't really staffed with
people I'd trust anywhere near my car.

>Like I said, I still have the original alternator (right size too!)
>but I left it outside and it won't spin. I sprayed it with PB, but
[quoted text clipped - 5 lines]
> Don't really feel like dropping ~150$ into this old thing. Like I
>said a great runner, but old is old...

Take it to a real alternator shop.  Look in the yellow pages under
"Alternators" or "Starters."

ANY car that comes with a spare alternator in back is kind of suspect.
You're sure the alternator you put in isn't one that had been previously
replaced?
--scott
Signature

"C'est un Nagra.  C'est suisse, et tres, tres precis."

JustMe - 28 Dec 2007 22:42 GMT
> So, you bought this car, and it came with a spare alternator in the
> trunk.... and before something failed and you put the spare alternator
> on, but it turned out to be a failed fusible link.
>
> Ohhh-kay.

Oi no, it was a bad fuse that was preventing the charging circuit
from doing it's job. The first guess is the alternator, no? So being
there was one in the trunk, I threw it on (and left it on). That's
when I realized the old alternator wasn't bad. Oi.

> The chain stores hardly ever carry rebuild kits, because they want
> you to buy their crappy rebuild.  Stay away from Carquest and Advance
> and take the alternator to a real alternator rebuilder.

Well I called a rebuilder and he wanted 98$ for a rebuilt unit, with
the swap. Car quest wants ~142$ for a rebuilt unit. So...I called the
junkman and he had one on the shelf for 40$. I threw it on and it
works.
Now I have 2 old alternators (he wanted my old one, but I opted to
pay 5$ to keep it). I want to learn how to replace bearing and fuses
and diodes (basically that's all there is I reckon - regulator is in
the computer). Winding rarely go bad on these things I take it, but
even then I could have someone rewind it for me.

> What parts store?  Most of the chain stores aren't really staffed with
> people I'd trust anywhere near my car.

The Carquest near me has a few gurus on hand. At least one dude is
pretty professional. And yes I did take it to them to get tested, and
they told me it wasn't putting out (he was of the persuasion it wasn't
bad brushes, but probably bad diodes).

> ANY car that comes with a spare alternator in back is kind of suspect.
> You're sure the alternator you put in isn't one that had been previously
> replaced?

Well my dopey nephew used to work at a NAPA, and I'm thinking that's
where/when he got it. Neither the spare battery cables nor the
alternator were right on, but the alternator did work at least (for
the better part of 10 months basically).
Anyway problem fixed. Thanks for all the help!
aarcuda69062 - 24 Dec 2007 14:02 GMT
In article
<1d700673-9130-42c6-8f55-fb3163014cda@f52g2000hsa.googlegroups.co
m>,

> drained one battery already. Installed a new one, but am only reading
> 11.8 volts while car is running (12.2 while car is off). There's about
[quoted text clipped - 11 lines]
> can't remember, the meter on the dash was reading a bit higher then
> normal (I guess a volt or 2?). Prior thanks for any suggestions.

2 door or 4 door?
(the circuitry is different between the coupe/convertible and the
sedan)

This is a very simple charging system, a few voltage checks and
jumpering one wire to ground  will diagnose 99% of all charging
system problems.

Also; did you check for trouble codes?
JustMe - 25 Dec 2007 01:54 GMT
> In article
> <1d700673-9130-42c6-8f55-fb3163014...@f52g2000hsa.googlegroups.co
[quoted text clipped - 25 lines]
>
> Also; did you check for trouble codes?

2 door convertible. No codes, no check engine light (not continuous
anyway. When I first noticed the problem, the check engine light did
come on after starting it. Then another warning light - right above or
below the check engine. Just can't seem to remember what it was, but
it's common. Granted when the battery voltage goes down low enough,
the C.E. light will come on and stay on I gather). Trouble codes don't
always tell you much. Before determining the problem was a fuse the
last time this happened, I got 2, then an additional code that didn't
tell me anything.
aarcuda69062 - 25 Dec 2007 18:15 GMT
In article
<1dbae4e9-197c-4300-a2d6-eb793c8c0521@e6g2000prf.googlegroups.com
>,

>  2 door convertible.

Okay, good.

> No codes, no check engine light (not continuous
> anyway.

It would be very unusual to have a charging system problem and
-not- have any trouble codes stored.
There are codes for low voltage, high voltage and field circuit
problems.
Not all problems will trigger the check engine light even though
they do store codes, so, don't assume that because there is no CE
light there aren't any codes stored.

>  When I first noticed the problem, the check engine light did
> come on after starting it. Then another warning light - right above or
> below the check engine. Just can't seem to remember what it was, but
> it's common. Granted when the battery voltage goes down low enough,
> the C.E. light will come on and stay on I gather). Trouble codes don't
> always tell you much.

They tell me much.

> Before determining the problem was a fuse the
> last time this happened, I got 2, then an additional code that didn't
> tell me anything.

Okay, you've got 12.2 volts across the battery engine not
running, you've got 11. 8 volts with the engine running, that is
obviously a no charge condition.

Refer here;
http://www.autozone.com/az/cds/en_us/0900823d/80/08/b6/90/0900823d
8008b690/repairInfoPages.htm

Figure 1

The terminal labeled B+ should have the same voltage as what you
measured across the battery.  This proves continuity between the
alternator and the battery.  There is a fusible link in this
circuit.

The terminal labeled A142 supplies the alternator field with 12
volts whenever the ignition switch is in the on position.
Fuse #16 protects this circuit.

The terminal labeled K20 is toggled to ground by the SBEC (engine
computer)  at the SBEC it is terminal 20 and is a dark green wire.

Knowing all this, all you need to do is check for voltages where
they should be under the conditions I described.

Next, connect  (key off engine not running) an ohm meter between
the A142 and K20 to check continuity thru the alternator rotor
and brushes.

If all is good, with the engine running, connect a jumper wire
from K20 to a good ground, this is called 'full field'  you are
now bypassing the voltage regulator function of the SBEC, if the
alternator is now charging, you have a wiring problem to the SBEC
or the VR in the SBEC is hosed.
boxing@sasktel.net - 24 Dec 2007 18:20 GMT
I took an alternator in once to Parts Source. They tested it out right
there on the spot. Maybe a parts store nearby will test it out for
you. Call before you go so you don't waste a trip.
 
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