Electrical Issues

[KBWoodwgn]

Hi Everyone,
I'm psyched because I've got the woodwgn back on the road. I swapped out the alternator (finally)and we seem to be charging... I do have one concern which maybe you folks can ease. I seem to recall that My truck ran at about 14 volts at Idle before this all happened. Now with the new alternator it's struggles to maintain 12 at idle. I can get it up a little over 13 while driving but 14 is like a distant dream.

Now it does idle seam like the idle is a little low (lower than before, don't know why) if I adjust that slightly do you think that would help?
kb

[GaWd]

Well, if it's below 14, the alternator isn't charging fully. Does the belt slip? Are the pullies aligned?

Also I'd check the output at the alternator and battery with a multimeter and see if it's not just your gauge. Polish up the ground a touch, and make sure your alternator connections are good and tight.

Sam

[joe]

You should be putting out something in the 14.3v-14.6v range. If it's barely making 12v you're not charging the battery. If the old alt was doing 14 and the new one is doing 12 and you haven't changed any wiring/elect stuff besides.replacing the alt...take the alt back and get another one. In the past I've had to go through two or three new alts or starters etc from the junk store chains like AutoZ, Schmucks, PepBz etc before finally getting one that works. Then getting the junk stores electrical stuff to last is another story :(

[KBWoodwgn]

Thanks guys, It doesn't look like the belt is slipping but I'll check and make sure I got the pullies tight and that they aren't slipping. I Did shell out and get a brand new alt from the dealer...I'm guessing it's possible that it's still bad...and no I didn't change any wiring at all.
kb

[Bob Barry]

Also make sure you use both belts; some replacement alternators only come with the single pulley unit, and if you use that with only one belt, you may be getting some slippage. It's SOP to swap the pulley from the old alternator to the new one, if the new one is a single.

[ChrisCollege]

kb,

You didn't mention it but the last time I changed out my alt. in the process I took out the battery and checked some grounds. If on the outside chance you were checking grounds or took out the battery go back and check them again. Often on our old jeeps grounds get loose or corroded nad go bad at the wierdest time.

[KBWoodwgn]

Ok, My Dad and I looked at this again last night. We checked the Battery and we were getting 12 volts off of that. We tested the output from the Alternator and the readings were slightly higher than what I was reading from the gauge inside the truck(not much higher, but higher). We checked the belt and the pulley and they were tight(no slippage). The idle seemed low and actually stalled out on us once while we were working. So I climbed in and just barely touched the gas....at that point it leveled out. So I adjusted the idle about a quarter of a turn. That brought the Voltage up to an acceptable range on the handheld meter. When I drive it It's safely over 14 by the gauge inside(that may be how it was before I can't remember).

Does any of this make sense? When I originally posted this question and suggested adjusting the idle as a possible rememdy nobody said anything(about the idle). Have I possibly fixed my problem or have I just masked the symptom? What do you folks think?
kb

[Bob Barry]

It sounds like you fixed it; alternator output drops quickly below a certain rpm level. It seems your truck was simply idling too low.

[KBWoodwgn]

Hey Bob,
I'm still a little leary, I kicked on my ac at lunch time and it dropped back to the low levels....I know ac puts a drain but should it be that bad...(ps my ac doesn't realy work I was just trying use it's fan to move some air it's realy hot today)
thanks for your help
kb

[WudreauxTWW]

I think you are right to be a bit leary. When you turn on an accessory like a fan the voltage regulator in the alternator will sense the load and try to maintain the same voltage output. It may spike down momentarily, but it should come back to very close to the original voltage. I had a similar problem in my rig and found the wire running from the firewall over to what I assume is the starter solenoid was laying against the engine and had gotten hot enough to melt through the wire to the point where it was shorting to ground preventing the battery from charging. I didn't notice this until I had a new battery, new battery cables, a couple new alternator, and a membership to hairclub for men..... I have seen other responses on this site that indicate that my experience isn't terribly unique.

[BIGYELLOW78J10]

I won't claim to be an electrical expert, but what you describe seems normal. The alternators our rigs were designed with, charge the battery when above idle. So the goal is proper charging at reasonable RPM. I'd say your alternator was probably working alright before the idle was adjusted. So long as you were getting a 14v charge, when running around it was normal. Aslo the A/C normall would kick up the idle to balabce out the compressor running, but if you do not need A/C all the time, then I wouldn't adjust the idle to compensate.

To end my long winded rant, I think the atlernator is working right. I also think you should check your idle as described in the haynes manual or off the site. As long as you are getting proper charge in motion, you should be good.

Daniel

[Bob Barry]

The A/C not only drags down the available volts, but the idle speed as well. Combined, they can lower your system voltage noticeably.

Is your idle set to 650rpm in Drive? Maybe bump it up to 700rpm.

[KBWoodwgn]

I guess I'm gonna have to get my hands on a handheld Tach....We just turned it up slightly so it didn't sound like it was croaking....Basically I have no idea what rpm's I'm running at...

[Bob Barry]

If you're going to tune your own engine, the two indispensable tools you need are a timing light and a multifunction engine-tester (they usually measure rpm, volts, amps, dwell, etc; they have come down in size and price since I bought my Craftsman unit over twelve years ago). They'll cost you less than two hours of shop time, and you'll use them again and again and again.

The other nice thing would be a distributor wrench; not necessary, but it makes it sooooo much easier.

[jeepbob]

The proper output for any alt is from 13.6 to 14.2 volts. Any higher and you can boil the battery lower and it will not charge properly. The factory gauges for the most part are not the most accurate in the world so get a voltmeter and check it. Or if you have a non-computer rig you can pull off a battery cable and if it stays running it is good. If you try this old hack method on a computer controlled rig you will be buying an alt and a computer, so don't do it.
Some test equipment to buy that does not cost a lot: a hand held engine analizer, a battery tester, and an alt full field tool. Also a handy tool to have is a short finder. Don't forget to buy a good 12v test light.