'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.

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.

that's the problem, closest auto electric specialty place I know of is

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

Nate Nagel wrote in news:iik7ol02km1 @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.

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.

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

-jim

Not today, it was about 30 degrees and raining and I had stuff that needed to be moved. Normally I would have...

accessories off I don't think it's dropping off much, but acc's on they seem to. Idle in Drive is about 600-700 RPM if the tach in the dash is to be believed.

nate

you need to put a meter on the battery while the motor is running to see what your charging volts are.. Anything below 13.5v you should replace the alternator.

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

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

N8N wrote in news:d8e42346-826a-4e58-bedd- snipped-for-privacy@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.

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".

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.

Dash gauges are worthless at best. Totally misleading usually.

Get a good, accurate, volt meter (VOM, DVOM) and measure the battery voltage with that. You should have about 13.8 volts DC when engine is running. If it drops below 13.2 volts, then there is a problem with the charging system, battery or cables/connections.

Also don't throw parts in without proper diagnostics.

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

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.

N8N wrote in news: snipped-for-privacy@a5g2000vbs.googlegroups.com:

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.