Alternator not charging

[Jobert]

My 2002 Explorer 4.6 V8 alternator is suddenly not putting anything out. It's apparently been this way for about a month or so but hasn't been a problem since I have been keeping the battery charged since I found the problem and don't use it at night, etc. I have other transportation available.

My question is: Should I be checking anything before I just go out and buy a new alternator?

I'm very much mechanically inclined and if you check my relatively few posts you'll see that I purchased this ride last August with a spark plug blown out (and a prior helicoil repair that didn't hold) which I repaired shortly thereafter and which has been fine ever since (knock wood). So any suggestions on testing the alternator would be welcomed and much appreciated.

I did search the forum but didn't find anything helpful so far, so I figured maybe I should just ask.

Edit (update): Well, since I posted, I saw some "similar threads" with suggestions, so I'm checking those out. Also, I have to check but I think that my charging gauge is indicating that the battery is charging. I actually never really checked it but I live in NJ and it's been quite cold at times so I warm it up well before driving it and check the oil pressure in particular when I first start it. I believe the alt gauge is right next to the oil pressure and I think it shows it charging. I'll check and update accordingly. Also, I don't think I have a warning light if it's not charging, but if I do that has never come on. But I know it's not charging because I check the battery terminals for voltage when it's running and only get 11.5 volts, if that. Plus I only found out about the problem when the battery was too dead to crank it one morning. And it got so low that my trip odometer reset to zero.

 

[Joe in NY]

Don't rely on ford dash gauges for anything. They suck. As long as your battery is above 0 volts, it will pretty much stay in the middle no matter what. I verified this by turn everything on without the engine running and got the battery to below 11 volts. Gauge didn't budge. Started it and let it come up to 14+ volts. Didn't budge.

the oil pressure gauge only indicates at least 5 psi. so if it suddenly goes from 50 psi to 10 psi while your engine is failing... (as happened to me before) you will never know.

The battery light is for the alternator. It has to excited in order to work. The light limits the current going into the exciter winding for the alternator. What is going is that you need to start the magnetic field for the alternator every time you spin it up from a stop. The light goes out because that same winding is now creating voltage at a very low amperage and since there is 12volts on either side of the bulb it goes out. So this tells us that the exciter winding is ok if your light is going out.

 

[Number4]

Easiest thing to do would be to take it to a part store and have them test it. You could do some voltage drop testing to make sure that you don't have any high resistant wires in line.

 

[Jobert]

Don't rely on ford dash gauges for anything. They suck. As long as your battery is above 0 volts, it will pretty much stay in the middle no matter what. I verified this by turn everything on without the engine running and got the battery to below 11 volts. Gauge didn't budge. Started it and let it come up to 14+ volts. Didn't budge.

True enough. I looked at the pdf of my owners manual to see the instrument panel, then went out and turned the key on. The charging gauge went up to the middle and stayed there. So that's consistent with what you said and also with what I've been seeing. So I was assuming that was "normal." (I frankly never really monitored it when the alternator was charging).

Also, the battery indicator light lit up and stayed on with the key on and the engine not yet started. The manual says it's supposed to "light up when the battery is not charging properly" but it's not been lighting since this problem cropped up. I surely would have noticed it, especially since my CEL light has been on since I bought this ride. It keeps giving me a P0357 error code and I suspect that it's a fluky wire in that #7 cylinder due to the spark plug having blown out twice and likely knocked the wiring around for who knows how long.

I didn't start it up but will note the charging gauge next time I drive it, tho' I'd say it likely has just been staying where it is now with the engine not running.

The battery light is for the alternator. It has to excited in order to work. The light limits the current going into the exciter winding for the alternator. What is going is that you need to start the magnetic field for the alternator every time you spin it up from a stop. The light goes out because that same winding is now creating voltage at a very low amperage and since there is 12volts on either side of the bulb it goes out. So this tells us that the exciter winding is ok if your light is going out.

And it is indeed going out with the engine running and the alternator not charging the battery. Seems like a bad system to me cuz my alternator isn't working and this light isn't warning me about that situation.

So, any testing I should do before I go buy an alternator?

Thanks much for the feedback.

 

[Jobert]

Easiest thing to do would be to take it to a part store and have them test it. You could do some voltage drop testing to make sure that you don't have any high resistant wires in line.

Thanks for that. I'll give Autozone a call and see what they have to say about testing it.

 

[TechGuru]

Around here Autozone and OReilly's Auto both test alternators (and starters) for free.

Here's you a Bosch: http://www.ebay.com/itm/Alternator-BOSCH-AL7541X-Reman-/111471837601

 

[Jobert]

I think I'll pull the alternator and check the brushes. It may just need brushes because it likely has a lotta miles on it.

I have another issue (question, actually) that I'll post on a new thread now.

 

[Joe in NY]

If the charging/battery light goes out after start up (normal operation) then messing with the brushes will not help. The actually alternator is a three phase generator with a diode rectifier bridge for each phase. Usually the diodes start to die which kill the voltage regulators

 

[Jobert]

If the charging/battery light goes out after start up (normal operation) then messing with the brushes will not help. The actually alternator is a three phase generator with a diode rectifier bridge for each phase. Usually the diodes start to die which kill the voltage regulators

Thanks. I'll keep that in mind.

I looked at removing the alternator a bit ago. Any suggestions on removing the belt, or can you guide me to a link?

My Suburban was pretty easy on that score because the tension pulley was easily accessible. But this Explorer looks like the tension pulley (if it's the one I think it is) is pretty inaccessible.

So any advice on removing the belt would be appreciated.

 

[Mr. Alligator]

Serpentine belt...

To remove serpentine built, use standard socket driver and a pipe as a breaker bar to gain leverage on the tensioner.

When you put serpentine belt back on, make sure it goes into correct tracks. Any deviation will create problems. You might have a diagram near your radiator. Or maybe take a picture. Also, you can pay attention to the the tracks or rear flat of the belt, in relation to the pulleys grooves or flats, to make sure you get that right. I once put the belt under a pulley it should have gone over, and created odd fitment problems until I figured it out. Odd how close it came to fitting!

You should find it fairly easy. And make sure to disconnect battery during this service, or else the cable on the alternator cable will have 12 volts of power.

Good luck with your project.

Mr. Alligator

 

[Jobert]

To remove serpentine built, use standard socket driver and a pipe as a breaker bar to gain leverage on the tensioner. ...
Mr. Alligator

Just looked things over and I see what you mean ... BUT ...

it's a pretty tight fit with the fan kinda in the way. I tried it from both above and below and I think I'll be doing it from above.

It looks like something that's prime for a special tool and I wouldn't be surprised if there is one; and that the mechanics who work in the dealerships use.

 

[Number4]

There are special tools for the serpentine belt removal.

http://m.harborfreight.com/serpentine-belt-tool-kit-66344.html?utm_referrer=direct/not provided

 

[Jobert]

There are special tools for the serpentine belt removal.

http://m.harborfreight.com/serpentine-belt-tool-kit-66344.html?utm_referrer=direct/not provided

Oh yea!

THAT'S what I'm talkin' about!

Thanks much for that. Should make the job easy.

 

[TechGuru]

I can't speak for the V8 but on the V6 belt removal/replacment is very easy.

BTW, while you're at it if it's time for a new belt get a Gatorback (now called Continental Elite)

http://www.rockauto.com/en/moreinfo.php?pk=1332904

 

[Number4]

Correct me if I'm wrong but my understanding of the Explorers charging system, is that if the Alternator isn't charging, not sending a GENMON signal to the PCM , then the PCM would kill the car. At least, the cluster would start behaving eratically, radio would cut out.

If it's sending a signal, but not the correct one, same thing, erratic cluster and idle.

You're not getting the light and you know the light works. You tested the battery voltage but did you test the alternator output? I just skimmed over the thread and don't see it mentioned, forgive me if it was.

With the car running, put the positive probe of your multi-meter on the stud of the alternator (where the large cable attaches) and put the negative end on the negative battery post. This will tell you how many volts the alternator is putting out, at that time. It may be a bad battery cable, not allowing for proper charging, or it could just be the battery.

 

[Jobert]

Correct me if I'm wrong but my understanding of the Explorers charging system, is that if the Alternator isn't charging, not sending a GENMON signal to the PCM , then the PCM would kill the car. At least, the cluster would start behaving eratically, radio would cut out....

Thanks much for the diagnosis tip. I will definitely check it out as you suggest and let you know what I find.

As I think I said before, I've only owned this ride since last August and it took me a month to correct the problem it had (spat out spark plug). I had previously tested alternator charging at the battery with my voltmeter and got 14+ volts (or whatever it was). I did that several times because I also had the dreaded "courtesy light problem" where the dome light(s) and rear view mirror lights come on whenever they feel like it, which then drained the battery. I solved that problem by making sure I turn the dash lights all the way off except when I'm actually driving at night.

It has 172+K miles on it and the guy I bought it from was the 2nd owner. He said he bought it with ~66K miles and a blown engine, so he got a "crate engine" and had that put in. So it would seem that this alternator has 100+K miles, and I suspect the brushes may be worn out since it WAS charging until very recently.

And just yesterday I noticed that my Reverse Sensing System is no longer working properly. The "off' light on that switch was lit (never was before) and it's not warning me like it had been when I backed too close to something.

I really like this ride a lot but it sure has had one problem after another in the short time I've owned it. Also had the "blend door" problem and also the "CD won't eject" problem (resulting in a free Dave Matthews Band CD), but those issues were likely already there when I bought it (not that I was told, however).

BTW, while you're at it if it's time for a new belt get a Gatorback (now called Continental Elite)

http://www.rockauto.com/en/moreinfo.php?pk=1332904

https://www.youtube.com/watch?v=cT8f0t9O3pM

Thanks for the recommendation. I'll keep that in mind if I need one.

 

[Jobert]

... So it would seem that this alternator has 100+K miles, and I suspect the brushes may be worn out since it WAS charging until very recently....

Took the alternator off today and here's what I found:

The brushes aren't all that worn ... BUT ....

The front armature (on which the front brush sits and makes contact with) is rather seriously worn down. I have no idea why that would be but there it is. As a result, it looks like maybe that brush isn't making solid contact with the armature, or what's left of the armature. So I will try "thinning" that brush out somewhat so that it can squeeze down inside the "rut" that the wear has created and make more solid and complete contact with the armature. Then I'll put it back on and see if the thing puts out voltage.

Obviously that will be a temporary fix (assuming it works) but I'm curious to see if it does.

Also, I tried pulling these brushes out of the holder they are mounted in and I could not get them out. I didn't want to ruin the springs in the process, so I didn't give them a good firm yank.

Dunno what the deal is there. Maybe ya buy a whole unit? It's held on by 3 screws so maybe that's what the deal is.

And just yesterday I noticed that my Reverse Sensing System is no longer working properly. The "off' light on that switch was lit (never was before) and it's not warning me like it had been when I backed too close to something.

Dunno what's up with the RSS problem that I saw recently but it worked normally on the last two trips I made with it. And the "off" light on the switch didn't turn on at any time.

When I was having the problem I could get it turned off, but then whenever I shifted into reverse it came back on.

 

[Jobert]

I did as per my last post and the bad brush did seem to make better contact with the armature, but it's still not charging. So it's off to Autozone to have it tested.

 

[Jobert]

...Also, I tried pulling these brushes out of the holder they are mounted in and I could not get them out. I didn't want to ruin the springs in the process, so I didn't give them a good firm yank.

Dunno what the deal is there. Maybe ya buy a whole unit? It's held on by 3 screws so maybe that's what the deal is...

Just FYI, I see that indeed the brush assembly AND regulator are a unit (and available on ebay):

100% New Alternator Voltage Regulator & Brushes For Ford Lincoln Mercury

http://www.ebay.com/itm/100-New-Alternator-Voltage-Regulator-Brushes-For-Ford-Lincoln-Mercury-/361441688425?fits=Year%3A2002|Make%3AFord|Model%3AExplorer&hash=item54279a7b69:g:ukgAAOSwbdpWXxGp

I was wondering where the voltage regulator was -- and now I know.

Also, when I previously referred to the "armature" I was actually talking about the "slip rings," which are also available on ebay:

Ford Alternator SLIP RING e f series, explorer, Mustang ect.. brush races

http://www.ebay.com/itm/Ford-Alternator-SLIP-RING-e-f-series-explorer-Mustang-ect-brush-races-/231138741283?fits=Year%3A2002|Make%3AFord|Model%3AExplorer&hash=item35d0f14c23:g:nDMAAOxyyvRSNCmG&vxp=mtr

If I was sure either of these parts was the problem, I'd get them. Surely I do need the slip rings and the brushes, so I guess the regulator would just tag along.

But I may have a bad diode, rectifier, etc.

 

[Jobert]

...Also, when I previously referred to the "armature" I was actually talking about the "slip rings," which are also available on ebay:

Ford Alternator SLIP RING e f series, explorer, Mustang ect.. brush races

http://www.ebay.com/itm/Ford-Alternator-SLIP-RING-e-f-series-explorer-Mustang-ect-brush-races-/231138741283?fits=Year%3A2002|Make%3AFord|Model%3AExplorer&hash=item35d0f14c23:g:nDMAAOxyyvRSNCmG&vxp=mtr...

Turns out that slip rings link isn't for my 2002 Explorer XLT 4.6L V8 and the seller has advised that he will change it as fitting my alternator because, he says, I have a 4G alternator.

Which appears to be correct.

See here:

How to Identify Your Ford 3G, 4G & 6G Series Alternator

https://alternatorparts.com/ford-type-3g-4g-6g-series-high-output-alternators.html

My alternator is shown in the top 2 pictures of the "4G Series Alternators" and does indeed have the "black metallic cover on the rear."

I note that the above ebay listing has now been corrected to reflect that it fits only the 4.0L V6 and not the 4.6L V8

Interestingly, I took the alternator off again yesterday to see if I would be able to install those slip rings, and thus also removed the brushes/regulator assembly. I found that there was no way I would be able to install the slip rings so I put it all back together and back on the truck.

Whereupon I found that it was actually putting out about 13 volts, as opposed to putting out nothing previously.

Must have been due to having "reseated" the front brush such that it was now making some contact with that very worn slip ring.

I've ordered a new alternator because this one is beyond my ability to repair it.