'93 F-150 - possible alternator problem?

Nate, it may or may not be normal.  If you have a good alternator/starter
shop where you live, that is where I would take it.  They can test the
whole system.

 I have had a lot betterluck with getting starters there than at most FLAPS.

In fact, I have had some brand new GM starters that didnt last worth
a darn.

On 02/05/2011 04:13 PM, hls wrote:

that's the problem, closest auto electric specialty place I know of is
50 miles away, next closest about 70, and while I've had mostly good
luck with the one 70 miles away (used to live near there) the Delco 10SI
in my Studebaker which I had them rebuild for me rather than going with
a parts store reman (which was kind of dumb, because they're super
cheap, and I paid close to $300 to theoretically have it "done right."
Next time I will mail order a kit and do it myself, now that I know the
windings are OK) exhibits the same behavior.  In that case I'm not 100%
sure if it's a pulley mismatch or an actual fault with the alternator
though.

I did have the same behavior with the original F*rd alternator on the
truck and when I took it to my FLAPS (not auto electric shop, but an
independent FLAPS that has since become a NAPA) to have it tested they
said to run it and not worry... and it died maybe 4K miles later :/

I am just kinda paranoid as the truck is almost 20 years old and I don't
want to get stranded somewhere...  I try to keep everything in top shape
and repair/replace anything questionable immediately, but then I run
into stuff like this... I have also cleaned/greased all accessable
underhood electrical connections prior to alternator/battery
replacement.  Not about to give up on it unless something really
tempting comes along as the A/C still works, and it has fairly new (all
within last 10K miles) brakes, shocks, tires, alternator, battery, fan
clutch, wiper motor etc. and I also changed all fluids except for
coolant (PO had just had it flushed) and P/S (been meaning to do that
but haven't yet) in the same period.  Only has 145K miles on it now...

nate

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Given the sub-zero temps and 45 ft of snow on the roof of your house, I'd
consider anything that runs to be normal. Wait until good weather before you
get too worked up. I suspect that in good weather, the problem will go away.

On Sat, 05 Feb 2011 13:22:12 -0800, Jeff Strickland rearranged some
electrons to say:


I would say that the alternator not charging problem is not weather
related, and is not likely to "go away".

It is not NOT CHARGING, it simply moves the needle due to the heavy load and
cold temps. My guess is that the battery suffered because of the cold too.

@news7.newsguy.com:


My first approach would be to put a digital voltmeter across the battery
terminals with the engine running. Have you done this?

Park the truck pointing at a wall or someplace where you can easily see the
headlight beams. Rev the enngine. Do the lights get brighter as the revs
rise, then dim as they drop back to idle? Try this with the accessories off
and on.

--
Tegger

If true, what does it mean?

I think the OP is buried under umpteen feet of snow in a climate that is a
bazzilion degrees below what it takes to sustain life, and his electrical
system is simply showing the strains of the environment. For lack of a
better term, he needs to chill out.

On Sat, 05 Feb 2011 14:49:57 -0800, Jeff Strickland rearranged some
electrons to say:


Measuring the alternator output will tell you if it's is charging the
battery or not.  In the real world, a properly functioning alternator
will charge the battery no matter how much snow is on the ground.

Tegger wrote:


That isn't going to tell him anything he doesn't already know. The
lights will get brighter and dimmer. The gauge has already indicated
that the voltage is changing some. The question is that because the
alternator is weak or is the defroster and wiper motors or some other
load drawing more than usual. Does it have fog lamps?  Is the idle lower
than normal?

Unless it is a heavy duty alternator these things only put out about
25-30 amps at normal idle speed.

-jim

And if in fact the problem IS just a matter of the severe cold, then
upgrading to a heavy duty alternator may be a solution.  Because next
winter is going to be cold too.
--scott

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

On Feb 6, 8:04=A0am, klu...@panix.com (Scott Dorsey) wrote:

I wouldn't call this "severe cold" after all it was only raining, not
snowing or freezing.  But I am going to have a hard time
"troubleshooting" it as it pretty much lives in the parking lot at
work when I'm not driving it (long story.)

nate

8445bd017012@d2g2000yqn.googlegroups.com:



If you can start it while it's warm, it takes all of a few seconds to touch
a VOM probe to each battery terminal with the engine running.

Then it would take all of a few seconds to check for headlight brightness
fluctuation when revved up and down from idle.

I can't imagine that you'd even get very wet during all this.


--
Tegger

need a helper, as I don't feel comfortable leaving the driver's seat
while in "drive"

nate

just check it while it's in park... Never leave the car when it's in
drive. :)

The voltage dropoff, at least that I've noticed by watching the dash
gauge, does not occur in Park or Neutral because apparently the engine
is spinning faster enough that the alt. isn't working as hard...

nate

Why don't you pull the truck up to a wall, a fat lady, or other solid
object, then observe the behavior of the headlights from the driver's seat?

Do you even /own/ a VOM? They're very cheap these days, and dead-easy to
use.


--
Tegger

On 02/07/2011 08:32 PM, Tegger wrote:

*sigh*

yes I own a VOM.  I'm running myself ragged at work, don't have anything
resembling a workspace, truck is left at work because I don't have
anywhere else to park it (not well lit lot,) and it's been raining
and/or snowing for what seems like weeks.  I'm also spending my weekends
putting in 12 hour days trying to get my house ready for sale.  Usenet
posts are typically done on "breaks" at work when I'm just too fried to
do anything "useful" without a couple minutes of slacking, and/or when I
can't sleep.  So asking questions is quite a bit easier than poking
around with a meter.

I thought my question was pretty straightforward, is it typical for a
standard '93 or thereabouts Ford alternator to noticeably drop off in
voltage at idle with the accessories on?  Local mechanics don't seem to
think it's a problem but this is the only alternator-equipped vehicle in
which I've noticed this behavior (save for aforementioned Studebaker,
which doesn't exactly have anything remotely stock on it.)  Answer to
that question will determine whether I make a big deal out of it and try
to get alternator warrantied and/or replaced with something better.  One
would think with a brand new alternator and battery that I shouldn't be
having any issues at all.

nate

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On Mon, 07 Feb 2011 20:56:24 -0500, Nate Nagel rearranged some electrons
to say:


Your problem could have a multitude of causes. Or, it might not be a
problem at all.  Because you are unable to do any basic diagnostic work,
it's difficult to answer your question.   Report the charging voltage at
the battery terminals at idle,  and also at 2000 RPM or so.  As long as
it's above about 13.5 volts, then the alternator is doing a reasonable
job.  A voltage drop under load can be caused by a number of things,
corroded terminals,  bad wiring, bad switches, etc.  Without doing some
troubleshooting, and just shotgunning parts, you're wasting time and
money.  Of course, that is your choice.

Well, this is a Ford, so maybe there are issues I'm unaware of.

But to me, an alternator in good condition should be more than capable of
keeping the system voltage well above 13 even with full-load, and at idle.

Remember that alternators replaced generators for the reason that
generators were often unable to keep up with a loaded system with the
engine at idle.




True, but my point is that the gauge may be giving you a false indication
of what's actually happening. That's why I'm encouraging you to verify
whether the gauge is fibbing or not.


--
Tegger