Dancing Voltage???

[Tommy2000]

So, I have a newer battery, (5 Mo), new Pos batt cable, (1 Mo), new plugs and wires, and my voltage likes to dance around, for example, when I roll up both power windows, it dips down significantly, and then pops back up. When I have the lights, stereo, A/C on and hit the brakes, I am pretty low on the voltage meter...Is this simply time for a new alternator?

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93 Sport 4X4,
150k Mi,
Llumar Metallic Tinted Windows,
Aftermarket Drink-Holder console,
GTS Taillight Covers, Sony CD and
Boston Acoustics Speaks,
Bosch +4's,
Splitfire Wires,
Modified Airbox,
Factory Towing Package,
31x10.5 General Grabber AP's,
Gabriel VST Shocks,
155,000 Miles

 

[Skip Pendle]

Before you go after the alternator, check your ground cable from the battery, and all other visible ground connections under the hood. Also, have the battery checked for a low level or weak cell.

 

[Tom Wilk]

Also, check it with a good voltmeter. The factory meter is not really calibrated, and a small change in voltage could show up on the gauge as a somewhat larger difference. Ordinarily, you will get a small dip when running electric accessories, but it should not drop too low. Even with the headlights and brake lights on and the AC blower at max, it should stay above 12 volts with the motor idling in gear. Does the voltage increase when you rev it up a little?

Like skip says, check and clean all your connections before springing for any new parts. Battery cable terminals are notorious for getting corroded. Pull them both off and really clean off the metal surfaces. Also, check the connectors around the alternator, make sure they are clean and tight.



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Tom
99 Sport 4x4
SOHC
Auburn Rear & Gerald's old Shackles
265/75-R16 BFG AT's that weren't supposed to fit

 

[JoeC5]

Mine does the same exact thing and I just put in a brand new battery in less than a month ago. When i'm at idle with accessories running it goes down, but when i give it a little rev, it goes back up. Goes back down though when i take foot of gas. I dont understand why this is happening.

 

[kilroy]

Possible worn brushes, or dirty commutator in the alternator.

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97 Explorer XLT
V8 AWD
Snorkless box W/ K&N Filter
http://www.grandillusion.org/xlt.htm

 

[HellFire92XLT]

I have the same "problem". I have the dancing voltmeter but just when the windows are going up and down.... I assumed this was just a normal thing. Was I wrong?

 

[joe d.]

Dancing Voltage on '92

I have a '92 and have had this problem over a month now and still no clue what's causing it. My voltage drops when accelerating. If I realy punch it my battery light will come on. Someone told me they thought my belts might be slipping. Cleaned all pulley's and belt no help. I just had to get a new battery. The battery can only go so long being charged between 9-10 volts. Have no other clues, yet. If I hear anything I'll post. I think it's time to take it in to a pro.

Be a fountain, not a drain!

 

[Chav]

Same problem in my 93 4door 4x4 xlt with my foggers and on and headlights the gauge drops and when i tap the gas the lights flare. If the wipers are on and my foggers and my headlights are on at the same time with the blower on med. the voltage gauge will drop everytime the wipers move. I went ahead and put an excel alternator 130 amp and the problem didnt imporve at all so I returned it and went to the dealer. The mechanic gave me a fax from ford about the problem stating that this is a normal occurance in our year explorers and there should be no atempt to fix it because it is normal. And that is when I officialy gave up. So far no major electrical problems except my fuel sender and reciever fail every summer, but its always covered by the ford 1 year warranty. hehe. Good luck!! I hope someone finds the cure for this problem.

-Chav

 

[Isles4evr]

I had my rig stock for a little while. When I put my sub in the back, I noticed the dip in the voltage somtimes when I was at an idle (280watt amp). I then installed fog's. My battery dips signifantly when I'm idleing now, with the headlights, fogs, and the speaker on. It even moves back and forthe very slightly when I don't have any of them on. I was talking to a couple of techs at a car audio shop and they said I can do a couple of things. One, get a new alternator, two get a capacatator for the amp, or three get a bigger battery. They said the battery may not work as well though (may stop some of the problem but not all of it).
This is what I say you do. First, clean your MAF, there are instructions in the explorer tips part of this site, then pull your plugs and see what kind of shape they are in, cleaining them would be a good idea. See how that works, if not I would probably go with the alternator. I'm gona be adding more electrical stuff onto it, so the alternator is what I am going to do now, and then if it getts bad after that I'm gona put a new battery in too.

Hope this helps,
Chris

 

[Chav]

Yeah people told me the same thing. So eventually I got the optima yellow top battery, a 1 farad cap, and the new alternator. The new battery and cap helped so i kept them, but the alternator didnt do anything...not even easy my worrying. I'm beginning to believe the ford tech's fax and for now I am going to assume that this is normal because nothing has seemed to really help it out. I also had the ground and positive wires replaced after the car decided not to start at the shop. Funny how the car failed to start while it was at the shop and man it took them a while to figure out what was wrong. Anyway I hope my input helps. I hope that someone learns from my mistake of going out and spending hundreds to replace things like the battery and alternator only to find that it didnt help, but people told me to avoid going out and just replacing stuff. I did it anyway and i regret it now.

-Chav

 

[Isles4evr]

Oh man, that really sucks. I'm not sure on the amps that my alternator puts out, but I think that a 130amp might help me out. There is a local guy who deals in rebuilt alternators, and the might even be able to boost mine up. If I get a cap it will probably be a 1/2 farad. I was also thinking of getting a small rebuilt alternator, and a small battery, and running my extra electrical things to it. Can it be done? And is so, Anyone done this?

But basicaly the reason it dances while idleing, and then stops when you rev it or when you take off, is because the alternator is not spinning fast enough to recharge the battery right away.

Hope this helps,
Chris

 

[roadkill]

Let me share with you today!

Same deal, low/dancing voltages. Don't run the engine in Baja for a few days with the radio playing, then get the clicking noises when you want to start it up!

1- Explorer alt.s suck!

2- Replaced the regulator on the alt., about 20 min job, maybe $20.

3- Got a Die Hard, asked for the 1000 amp (not the std 750), no extra cost, same as the police/fire use.

Stabilized the bounce. Starts are Kick ass. Still looks like it's charging all the time, but I've been happy since!

If you go the coin get the optima, but it's warranty is 12mo (?) Die Hard 3yr full replace, 7yr total.

Enjoy your amps!

 

[Tommy2000]

More info-

RoadKill-

What is this $20 part, and where can I get it?

 

[roadkill]

The electronics part of the alternator is the regulator, bolted to the back, where the wires connect. I may be off on the price, but it was cheaper than a new alternator. I used a volt meter to test the alt. with the Haynes book, and it would charge when manually switched (see book). It was real easy to install. Ask your local parts store, or the ford dealer if you're brave!