Alternator bad? Voltage regulator maybe?
VanguardLH
3 years old and the car started a week ago. However, today it just
cranked like one turn and died. I can hear the relay click as I turn
the key but the engine doesn't budge. I also noticed the electric seat
belt moved slowly.
I popped the hood, jumped started from my other car, and with a
voltmeter measured across the battery. It measured 12.5V. As I recall,
each cell in a new battery should be 2.2 volts and there are 6 cells so
a new battery should measure 13.2 volts, so 12.5V isn't bad for a
middle-aged battery. However, I expected the voltage to be higher while
the car was running due to the output from the alternator. The voltage
also did not fluctuate when I revved the engine. It dropped a volt when
I turned on the headlights. So it looks like the alternator is bad.
While 16 years old, mileage is only 135K so, on average, the 2
alternators have lasted only about 67K which seems a bit short-lived
(actually the first one probably lasted 105K and the 2nd died after
another 30K).
I had to replace this alternator about 4 years ago. The prior run
burned up. Its bearing went bad and it heated up so you could smell the
varnish on the windings within a few blocks of driving from cold. It
was a rebuilt and is now out of warranty. I got it for around $80. The
salvage place doesn't have another alternator (except for a
retail-priced new one). I can get one for $118 at PepBoys with a
lifetime warranty; however, I'm wondering if just the voltage regulator
is shot. I can't see what the module is on the outside so maybe the
regulator is inside. If inside, I'm not dismantling it to replace that
module. I suspect if it is inside that it'll be riveted and positioned
where it won't be easy to get out to replace it, assuming that just the
regulator can be purchased and is much cheaper. If the voltage doesn't
get above what the battery alone will provide, is it even a voltage
regulator problem?
I can't find my battery charger so I'll call a buddy to drop by with
his. I need to charge the battery so I can get to PepBoys to have them
do an alternator test and have enough juice in the battery to start it
again to get the old Subie back home.
What should be the voltage across the battery while the car is running
and with a working alternator? I thought it was 14.4V. It would have
to be higher than the 13.2V for a new battery.
Is the voltage regulator inside or outside?
How trustworthy are these parts shop alternator testers?
Suggestions on how to go cheap on the alternator replacement? The
1-year salvaged rebuilt alternator lasted 4 years. Considering it was a
third the price, another 4 years is just fine with me.
johninKY
diode. Not worth tinkering with if you haven't rebuilt a few. You can
use a much newer alternator if willing to change the wiring plug.
Thinking 1994 was the year the plug changed.
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VanguardLH
<news:39d8253a719967c9...@localhost.talkaboutautos.com>:
> This alternator has an IR.
Sorry, but my primary career has been in computers. IR, to me, means
InfraRed, as in the light spectrum used by communication
transmitters/receivers. Maybe IR means Internal Regulator?
I just looked again at the alternator in my car and see nothing that is
accessible from the outside to let me swap out a regulator module. I
couldn't even find a tag that listed the amp rating. Any idea how many
amps the replacement alternator should supply? I think it is 70 or
maybe 80 amps. This car does have air conditioning (the compressor is
still in place but the system sprung a leak after a recharge and hasn't
worked in over 10 years - I'd like to remove the compressor to remove
any drag, if there was any since it is never turned on, but don't see
how to put a pulley there for the belt). Of the few places that
mentioned a rating, I usually see 70A units although 50A and 90A were
also mentioned.
> Problem probably is the alternator has lost a
> diode. Not worth tinkering with if you haven't rebuilt a few. You can
> use a much newer alternator if willing to change the wiring plug.
> Thinking 1994 was the year the plug changed.
Never rebuilt an alternator. My guess, based on the assumption that bad
luck is likely, is that I would open it up and find I had to dismantle
everything to get at a module that is riveted behind everything else. I
found a diagram of the alternator at http://tinyurl.com/6rx7so. Yep,
the voltage regulator is inside (on item #2). Looks like it might be
possible to open it up to replace just the "plate" holding the
regulator; however, the prices that I've seen for the regulator alone
are higher than the entire rebuilt alternator.
Splicing in a new plug wouldn't be a problem for me. I'm very handy
with soldering and heatshrink tubing to make a solid inline splice. The
problem would be getting the plug. I don't know that a new alternator
would include a matching plug. The rebuild that I bought last time
didn't include one. If I don't get one spec'ed for my car, I'm also
guessing the mounting plates and holes won't line up.
After checking some other maintenance receipts to figure out what the
mileage might've been at the time I replaced the alternator, the 2nd
alternator now in the car (which was the rebuilt replacement from the
salvage shop with 1-year warranty) only lasted maybe all of 20K miles
which seems damn short. The 72-month battery is only 16 months old. Is
it possible a weak or defective battery would result in the voltage
readings that I saw (12.5V across the battery terminals with the car
running)? It'd be easier to dump in a new battery than take off the fan
belts to remove the alternator and have to do it in reverse again. Even
if the battery were defective, I still expected the voltage to rise when
I revved the engine. Apparently to have the alternator tested at the
parts store means having to remove it from the car; i.e., they can't
test it /in situ/.
I have the following choices (for cheapest prices found so far), all of
which are rebuilds:
- ProStart brand: $118.99 (PepBoys; also at Advance Auto but I can't get
a price online and too late to call right now).
- Autolite (Pro-Tech) brand: $129.99 (Advance Auto or Checker Auto Parts
since both use PartsAmerica.com).
- O'Reilly Auto Parts (no brand identified other than "Ultima"): $119.
All have lifetime warranties. The Autolite unit includes a roadside
assistance perk (with a $60 max reimbursement). They didn't mention the
amperage rating so I'll have to check that tomorrow. Any experience in
which brand or store you like best for an alternator?
Tony Hwang
Sounds like your battery is drained by some unknown load or it is bad.
Probably one cell gone bad. If you can't test battery, try another one
then yo can decide. When charging the voltage should be ~14V. Is the
battery warm to touch?
Tony Hwang
I'd rather think I in this case stand for integrated or imbedded.
If alternator is really proven bad, it can be rebuilt if you want to.
Or hen you bring bad one it's worh a few bucks in exhcange.
johninKY
Only thing I found that always works is an impact gun. Once the pulley is
off just remove those long bolts running through the case and everything
falls apart. Just mentioning this if you decide to open it to inspect the
insides. When a diode fails the battery "back drains" through the
alternator which I think is your problem. Or at least part of the
problem. There are companies out there that sell new connectors but the
easy way to get the newer connector is to just cut one from a newer
wrecking yard car. You don't have a 90A alternator now. Use to know the
amperage output but now guessing in the 75A range. I have never had good
results with using rebuilds, or at least the kind sold at auto parts
stores. Quality over the years has been very poor.
johninKY
design.
http://www.stealth316.com/2-alt-rebuild.htm
VanguardLH
<news:020b13254bbe658c...@localhost.talkaboutautos.com>:
> The only difficult part opening up an alternator is removing the pulley.
> Only thing I found that always works is an impact gun. Once the pulley is
> off just remove those long bolts running through the case and everything
> falls apart. Just mentioning this if you decide to open it to inspect the
> insides. When a diode fails the battery "back drains" through the
> alternator which I think is your problem. Or at least part of the
> problem. There are companies out there that sell new connectors but the
> easy way to get the newer connector is to just cut one from a newer
> wrecking yard car. You don't have a 90A alternator now. Use to know the
> amperage output but now guessing in the 75A range. I have never had good
> results with using rebuilds, or at least the kind sold at auto parts
> stores. Quality over the years has been very poor.
While I might attempt dismantling the alternator (although I don't have
an impact wrench), the deterring factor now is the high price for the
voltage regulator replacement part. It costs more than the rebuilt
alternator, and the same price as a new alternator. No point in buying
just the part when I can get the entire unit for the same or cheaper
price. With a lifetime warranty (limited to the original car it was
installed in) and the much reduced price of a rebuild and the ease of
replacing the alternator (the belt and a couple bolts), I'll probably go
with the rebuild.
VanguardLH
No warmth to the battery (when unused or with the car running).
Even if the battery was bad, wouldn't the voltage across it go up due to
output from the alternator (when the car is running)?
Tony Hwang
No. because bad battery will load down the alternator like a partial
short. It happens when one electrodes inside battery cell shorts out.
Generally batteries cause more trouble than alternaotr/VG. Even brand
new battery can fail. One factor of better battery is mechanical rigidity.
VanguardLH
Took the battery to the car shop. The first handheld tester said Good
(but a recharge was needed but I already knew that). That included a
check for the short condition. Then they shoved in the big tester that
first charges the battery for 30 minutes (ho hum, wander the store) and
it tested okay. They also plug in the cold-cranking amp rating to check
the battery can supply that load (although 85F outside and 70F in the
store isn't really "cold"). Couldn't find my trickle charger at home so
picked up a 3-stage one at a different store where it was cheaper and am
charging the battery tonight. That's because this car shop says they
can test the alternator while in-place but it requires the car can
startup on its own while testing. They have an emergency jump kit to
let me start and drive back home but they need the car to be able to
start itself using the battery and alternator without being jumped. So
tomorrow I find out more.
AS
Before killing the alternator, a battery with a dead cell can prevent
the voltage from the alternator from going to normal charge levels when
measured at the battery.
Clean the alternator connections, make sure that the Alt S fuse
connections are clean, make sure that the connector that plugs into the
alternator is clean. Make sure that the fusible link and main fuses are
clean. Mind the ground connections and battery terminals as well.
Also, make sure that the v-belt is in good shape and that i has the
proper tension. I have seen them slipping with no squeal.
Charge the battery and measure the voltage at the battery when cranking.
It should be more than 9 volts. When the motor is running, a properly
charged battery should see 14.2 to 14.8 volts in a properly regulated
system (those that allow batteries to last for 7 years, ;) )
Good luck!
johninKY
VanguardLH
> Well. what was the problem?
Been busy replacing air conditioners, rebuilding windows, and cleaning
the yard of debris and hauling it away. Just haven't gotten to working
on the car yet this week beyond getting the battery charged. My buddy
is coming over (maybe) this Saturday or Sunday to help with more debris
(which reminds me that I have to get busy with the chainsaw) and getting
rid of a removed water heater. Afterward, he'll accompany me when
testing the alternator just in case I need a ride back or a battery jump
(although the store says they have an emergency boost kit). While some
car shops say the alternator must be removed, this one says they can
test with the alternator in place but the battery must be in the car and
capable of starting the car itself (no boost, no jump). So, for now, it
looks like this job waits until this next weekend.
Hmm, come to think of it, I should put the charged battery back into the
car and connect it up. If there is a leak in the wiring or other
component (or even through the alternator) then I might see this by next
weekend (although the battery might still be good enough to start the
car so I'm not sure this test will reveal anything).
Mike Copeland
> Hmm, come to think of it, I should put the charged battery back into the
> car and connect it up. If there is a leak in the wiring or other
> component (or even through the alternator) then I might see this by next
> weekend (although the battery might still be good enough to start the
> car so I'm not sure this test will reveal anything).
Before you reconnect the battery, put an ammeter in series with the
positive cable. You will see any current draw. If you get a current draw
pull the plug on the alternator and see if goes away.
VanguardLH
Good idea. I've got an old ammeter (Amp Probe) that I inherited from
dad.
VanguardLH
Did as you mentioned. The old ammeter didn't budge when I put it across
the "+" on the battery to the positive cable (with the negative cable
already connected to the "-" battery post), even on the 6A range. That
seemed weird since I know the radio is still hooked up and has a clock
in it. So I got out my DVM which has a 2A scale and it showed 0.438A,
or a little under half an amp. Odd part was that it showed -0.438A
(with red probe to cable and black probe on "+" battery post), as though
current was running to the battery instead of out. In any case, there
is a little bit less than an ampere showing on the DVM from the battery.
I left the battery disconnected until it's time to take in the car to
have the alternator tested. My buddy isn't showing up today so maybe
tomorrow.
Tony Hwang
Simple way to see excess ghost current is using a small 12V bulb in
seiries with battery cable. There is a very very small amount of current
flowing at all times for clock and such.
AS
drain current as positive if the red lead was connected to the battery +
post.
As far as the magnitude goes, did you read with all the accesories off?
It strikes me as a tad high, was the dome light on? something else on?
Good luck.
VanguardLH
> Vanguard wrote:
>>
>> Did as you mentioned. The old ammeter didn't budge when I put it across
>> the "+" on the battery to the positive cable (with the negative cable
>> already connected to the "-" battery post), even on the 6A range. That
>> seemed weird since I know the radio is still hooked up and has a clock
>> in it. So I got out my DVM which has a 2A scale and it showed 0.438A,
>> or a little under half an amp. Odd part was that it showed -0.438A
>> (with red probe to cable and black probe on "+" battery post), as though
>> current was running to the battery instead of out. In any case, there
>> is a little bit less than an ampere showing on the DVM from the battery.
>>
>> I left the battery disconnected until it's time to take in the car to
>> have the alternator tested. My buddy isn't showing up today so maybe
>> tomorrow.
>
> The DVM reading (-) is correct. The battery being the source would read
> drain current as positive if the red lead was connected to the battery +
> post.
Yeah, I figured that after thinking about it. The current would go out
from the "+" battery post so the red probe on the DVM on there would've
been backwards to the electron flow.
> As far as the magnitude goes, did you read with all the accesories off?
> It strikes me as a tad high, was the dome light on? something else on?
The only device that I know of that would've been on was the clock in
the radio. No lights, including dome lights, were on. The key was not
in the ignition switch so it wasn't even partially turned to enable some
of those circuits.
I figured if a diode in the rectifier were shorted then that might be
the cause of the drain through it. I found a basic schematic at:
http://www.alternatorparts.com/understanding_alternators.htm
If a diode were shorted, wouldn't that mean that there would be current
flowing through it (back to ground)? I always thought a diode would
blow open due to the heat of the leakage current but then these are
high-current diodes and the leakage current is only half an ampere.
Dave
news:DoqdnUZxHvMqV-zV...@comcast.com...
> AS wrote:
>
>
> Yeah, I figured that after thinking about it. The current would go out
> from the "+" battery post so the red probe on the DVM on there would've
> been backwards to the electron flow.
>
>> As far as the magnitude goes, did you read with all the accesories off?
>> It strikes me as a tad high, was the dome light on? something else on?
>
> The only device that I know of that would've been on was the clock in
> the radio. No lights, including dome lights, were on. The key was not
> in the ignition switch so it wasn't even partially turned to enable some
> of those circuits.
>
> I figured if a diode in the rectifier were shorted then that might be
> the cause of the drain through it. I found a basic schematic at:
>
> http://www.alternatorparts.com/understanding_alternators.htm
>
> If a diode were shorted, wouldn't that mean that there would be current
> flowing through it (back to ground)? I always thought a diode would
> blow open due to the heat of the leakage current but then these are
> high-current diodes and the leakage current is only half an ampere.
The reason the amp draw may be a little high is because of the keep alive
memory in the radio and computer. Here's how to get around that. Hook up
your amp probe as before between the +post and +cable. Now take a jumper
wire and place it between the +post and +cable. Leave it there for at least
15 seconds (some take up to a minute). At this point your amp probe will
read zero. Once you remove the jumper wire the probe should read much lower
than in your initial test.
All that is moot though as I agree with JohninKY's original post, you have a
bad diode since it's only charging 12.5 volts. BTW... that shop that says
they can't jump the car, then test the alt is suspect. It sounds like they
have an idiot proof tester of some sort and only have idiots to test with.
;-)
NAPA sells a very good reman alt with a lifetime warranty. Be sure to ask
for their premium line as they also have a cheaper line with a 3 year
warranty. They also sell a new one for many applications for not too much
more.
Dave
"Dave" <mec...@hotmail.com> wrote in message
news:g4vlg3$29q$1...@registered.motzarella.org...
>
> The reason the amp draw may be a little high is because of the keep alive
> memory in the radio and computer. Here's how to get around that. Hook up
> your amp probe as before between the +post and +cable. Now take a jumper
> wire and place it between the +post and +cable. Leave it there for at
> least 15 seconds (some take up to a minute). At this point your amp probe
> will read zero. Once you remove the jumper wire the probe should read much
> lower than in your initial test.
>
> All that is moot though as I agree with JohninKY's original post, you have
> a bad diode since it's only charging 12.5 volts. BTW... that shop that
> says they can't jump the car, then test the alt is suspect. It sounds like
> they have an idiot proof tester of some sort and only have idiots to test
> with. ;-)
>
> NAPA sells a very good reman alt with a lifetime warranty. Be sure to ask
> for their premium line as they also have a cheaper line with a 3 year
> warranty. They also sell a new one for many applications for not too much
> more.
PS I just reread your first post. That $118 alt from Pep boys is a great
price for a lifetime warranty! I once bought a $22 alt for a Chevy from
AutoZone. I asked if they had anything of better quality. He said it had a
Lifetime Warranty so I bought it. Darn thing lasted 8 years!
VanguardLH
> Dave wrote:
>>
>> NAPA sells a very good reman alt with a lifetime warranty. Be sure to ask
>> for their premium line as they also have a cheaper line with a 3 year
>> warranty. They also sell a new one for many applications for not too much
>> more.
>
> PS I just reread your first post. That $118 alt from Pep boys is a great
> price for a lifetime warranty! I once bought a $22 alt for a Chevy from
> AutoZone. I asked if they had anything of better quality. He said it had a
> Lifetime Warranty so I bought it. Darn thing lasted 8 years!
Each of the stores that I went to (after checking the warranty and
price) is selling a rebuilt for $118 to $129 and each has a lifetime
warranty (the $129 unit include roadside assistance to get a jump if the
battery is bad or, in this last case, the alternator won't charge the
battery so the battery is dead and I need a jump to start the car;
didn't get any details on how long that plan lasts). As I recall,
Napa's rebuilt ran around $179 for standard quality, $224 for premium,
and $290 new. This is for an old 92 Subie Legacy that gets maybe 7K
miles on it per year.
I figure if it has a lifetime warranty (for the original car in which it
gets installed) then I can pop in another if it fails. PepBoys has been
around long enough that they'll probably still be around for years from
now. O'Reilly has been around for maybe a couple decades (but when
through name changes). There are some things I won't buy from either,
like brake calipers or wheel bearing, but a lifetime alternator is okay.
Replacing the alternator is not much more difficult than taking out the
battery. Making sure I don't overtighten the belt is the only hazard.
VanguardLH
> The reason the amp draw may be a little high is because of the keep alive
> memory in the radio and computer. Here's how to get around that. Hook up
> your amp probe as before between the +post and +cable. Now take a jumper
> wire and place it between the +post and +cable. Leave it there for at least
> 15 seconds (some take up to a minute). At this point your amp probe will
> read zero. Once you remove the jumper wire the probe should read much lower
> than in your initial test.
Presumably the half ampere was flowing through the DVM (to measure it at
that rate) was for the clock/radio but I don't know if I left it
connected long enough to setup the clock/radio. I do know what you're
talking about because I had to replace the clock/radio (twice because
the salvaged unit failed but I removed its face to put on another
salvaged unit whose display was faded and had an iffy press button). I
can try what you suggest to see if the current draw drops after, say, a
minute of shorting the battery "+" to cable.
> All that is moot though as I agree with JohninKY's original post, you have a
> bad diode since it's only charging 12.5 volts. BTW... that shop that says
> they can't jump the car, then test the alt is suspect. It sounds like they
> have an idiot proof tester of some sort and only have idiots to test with.
The idea is to also measure the surge current while or after starting.
Although the battery itself passed their automatic tester (first a
handheld one and then in a load tester), they said one of the tests is
during startup. So, yeah, it might be an idiot tester but it's free at
the stores. A more complicated tester involving human cognition would
cost money. The one store said that the alternator can be tested in the
car. The others want me to yank it out so it can be mounted on their
tester (so its belt runs the alternator). While the alternator isn't
that tough to remove (and put back in), I'd rather not do it if not
necessary, plus an in-car test might find a different problem, like a
short in the harness, a short in a dash guage, or whatever.
I'm sure that whatever tester is used at whichever car part store would
all qualify as an idiot tester: follow hookup procedure, press a button,
and wait for a good/bad status. An idiot tester that tests with the
alternator in the car just makes it simpler for me to do the test.
Dave
> While the alternator isn't
> that tough to remove (and put back in), I'd rather not do it if not
> necessary, plus an in-car test might find a different problem, like a
> short in the harness, a short in a dash guage, or whatever.
You're making this more complicated than it is. Shorts cause fuses and
fusable links to burn out, not drag the voltage output down. You've already
determined the alt can't put out more than 12.5 volts even though your
battery voltage was well below that. It should have been putting out 13.8v,
if not more on a dead battery.
If you had a problem with your harness or dash gauge not energizing the
alt, or the alt voltage not getting to the battery, the battery voltage
would have read well below 12 volts, not 12.5v. 12.5v is sort of a magic
number. It shows the alt is trying but one of the diodes is burned out.
Testing it for amperage output like the shops want to do, whether on car or
on the bench tester, or testing for starter draw while cranking, isn't going
to show a different result. You really need another alt.
Dave
> Shorts cause fuses and fusable links to burn out, not drag the voltage
> output down.
Let me rephrase that: Shorts cause fuses and fusable links to burn out, not
drag the voltage output down - for more than a few seconds anyway.
Dave
Dontcha hate it when they never come back to tell you you were right, and
thanks for the help. I know I do. </talking to myself>
NewsGroupie
> "Dave" <mec...@hotmail.com> wrote in message
> news:g4vtr4$qot$1...@registered.motzarella.org...
>> "VanguardLH" <V...@nguard.LH> wrote in message
>> news:u9adncsjtdLy9O7V...@comcast.com...
>>
>
> thanks for the help. I know I do. </talking to myself>
just wantja to know..I feel your pain.
VanguardLH
I haven't had the time to take in the car. As I said, it usually just
sits in the carport. Since last November, I've probably put around a
hundred miles on it. Also, I was going to have my buddy come along in
case there was a problem with the car on the way to or back from the car
shop but he didn't call last weekend, I couldn't reach him, and he
called on Thursday to say he'd stop by to drop off his trailer (for yard
waste removal) but had to leave to prepare for his son's cub scout trip
that he was leaving on. A family member kept disappearing when they
said that they would help. I'd be pissed with both people if it weren't
that this is still a low priority repair. I really only have the
weekends to get at this problem but have gotten disappointed the last 2
weekends with promises of help but didn't get any.
I put the DVM from the "+" battery post to the cable and saw no amperes
this time. Was a bit surprised that there was no current flow but then
found out the 2A slowblow fuse had blown. So I'll disconnect and
recharge the battery and just remove the alternator to get a new one.
Everything points at the alternator so I'll just yank it out and get
another one (with a lifetime warranty this time).
VanguardLH
> All that is moot though as I agree with JohninKY's original post, you have a
> bad diode since it's only charging 12.5 volts. BTW... that shop that says
> they can't jump the car, then test the alt is suspect. It sounds like they
> have an idiot proof tester of some sort and only have idiots to test with.
Got a new alternator. Didn't bother driving in the car or removing the
old one to have it tested. Nothing else looked like the culprit than
the alternator. Used my newer car to pickup the alternator (from
PepBoys, $118 rebuilt, lifetime warranty), put it into my old 92 Subie,
and tested the voltage. The battery had already been fully charged.
Voltage was 13.93V so it was definitely above the 12.5V before. It
wasn't the 14.4V that I thought it was supposed to get to but the
battery was charged and I didn't have another person available to rev
the engine while it monitored the voltage to see if it went up.
So it looks okay for the alternator. I drove the old car back to the
car store for the core refund. Smelled something. Nope, not the
alternator (I've smelled a burnt alternator whose bearings went before
and it wasn't that varnish smell from the bearings getting super hot and
heating up the windings). It came from one side. Good grief, now the
front right brake is dragging. I put my hand on each wheel (well, on
the wheel cover) and the front right was significantly hotter. Could be
some rust on the slider pins is the problem since the car has been
sitting idle in the car port for 8 months and maybe just driving it some
will get rid of the problem. But just in case, I'm hunting around for a
brake inspection, preferrably free. I'll take it back to where I had
the brake pads replaced last summer. They worked on the calibers
instead of replacing them and one had a rust ring on one of the slider
pins that they had to burnish off. Might be the same problem again.