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grouch
02-01-2008, 11:36 PM
I have an old Jeep Wagoneer that I don't ever fool with. I'd like to get rid of it but nobody wants to buy a Jeep with electrical problems. It will not charge itself. I even wnet to the point of pulling the three wire alternator and putting a one wire on it. No joy. I'm well aware it needs to have a burst of rpms to energize the self energizing diodes. I added an extra ground strap to the body of the alternator. Still no joy. I then ran a 10 gauge wire in parallel with the power wire and it's straight hot. Still no joy. I've had both alternators tested by an auto electric shop. They can't think of anything. They said to bring it in and they'd go over it. At $65 an hour of course. I like to be able to repair the really bizarre problems but this one has me stumped. I moved it tonight after it sat for about 6 weeks. It fires right up and runs pretty good but will run the battery down eventually. :-[

DonTom
02-02-2008, 06:39 AM
"I have an old Jeep Wagoneer that I don't ever fool with. I'd like to get rid of it but nobody wants to buy a Jeep with electrical problems. "

Wrong! That's what I look for. The 1978 RV I bought many years ago had countless electrical problems. That's why I got it cheap. I fixed all the electrical problems in almost no time, but I wasn't expecting all the serious engine problems. But now I know about old 400 CID small blocks being very unreliable.

What year is your Jeep? If it's before the serpentine belt days, you might just have a bad belt! The most confusing charging problems I ever had was from a little oil on a brand new belt. The main symptom of this is that the charging voltage is higher at idle than just above idle.

If that's the case, try tighten the belt a lot more than normal and then see if the charging is better. It might only last about 20 miles before the problem comes back, but that was a symptom I had, because of leaking tranny fluid (see below). The belt makes no noise when it is slipping. Gives no other clue than the charging voltage going down as the RPM's go up. Would run fine during the day but could only go a half hour or so during the night when the headlights were on.

The problem never returned after I fixed (covered) the hole in the tranny tube and put on a new belt.

My charging problem was caused by a tranny fluid leak from the tranny dipstick tube that ran just above the alternator belt. Somehow there was a little hole just above the alternator belt and it would get a few drops (or mist) of tranny fluid on the belt. Especially after adding tranny fluid!

But this was in a GM 3/4 ton van, V8.

A single wire alternator takes more RPM's before charging. You were better off with the older style. Also, the single wire alternator MUST have a very good ground or it won't charge at all. Be sure there's no voltage between the alternator case and engine.

Oh, I see you added a ground strap. To the battery negative or engine? Don't use the vehicle frame.

And are your sure your battery is good? Even if new, check that there is water in it (if it's the type you can check). Once I had a screw on the battery plate that dug into a new battery and leaked all the water / electrolyte out. It took a while for me to figure out that my new battery had a problem! And I have also heard of people buying new bad batteries! Even selling a bad used battery as new by mistake!

Tell me what year it is and I will see if I can find a schematic of its charging circuity if nothing in this message helps.

-Don-

Eric
02-02-2008, 07:53 AM
I have an old Jeep Wagoneer that I don't ever fool with. I'd like to get rid of it but nobody wants to buy a Jeep with electrical problems. It will not charge itself. I even wnet to the point of pulling the three wire alternator and putting a one wire on it. No joy. I'm well aware it needs to have a burst of rpms to energize the self energizing diodes. I added an extra ground strap to the body of the alternator. Still no joy. I then ran a 10 gauge wire in parallel with the power wire and it's straight hot. Still no joy. I've had both alternators tested by an auto electric shop. They can't think of anything. They said to bring it in and they'd go over it. At $65 an hour of course. I like to be able to repair the really bizarre problems but this one has me stumped. I moved it tonight after it sat for about 6 weeks. It fires right up and runs pretty good but will run the battery down eventually. :-[


Don is a super guru on this stuff; I am hoping he will weigh in.... Don?

DonTom
02-02-2008, 08:37 AM
"I am hoping he will weigh in.... Don?"

How did you miss the previous post (the post before yours in this thread)?

-Don-

Eric
02-02-2008, 08:41 AM
"I am hoping he will weigh in.... Don?"

How did you miss the previous post (the post before yours in this thread)?

-Don-


Just saw it, actually - I get google-eyed sometimes trying to keep up with everything!

grouch
02-02-2008, 10:50 AM
What year is your Jeep? If it's before the serpentine belt days, you might just have a bad belt! The most confusing charging problems I ever had was from a little oil on a brand new belt. The main symptom of this is that the charging voltage is higher at idle than just above idle.

If that's the case, try tighten the belt a lot more than normal and then see if the charging is better. It might only last about 20 miles before the problem comes back, but that was a symptom I had, because of leaking tranny fluid (see below). The belt makes no noise when it is slipping. Gives no other clue than the charging voltage going down as the RPM's go up. Would run fine during the day but could only go a half hour or so during the night when the headlights were on.

The problem never returned after I fixed (covered) the hole in the tranny tube and put on a new belt.

My charging problem was caused by a tranny fluid leak from the tranny dipstick tube that ran just above the alternator belt. Somehow there was a little hole just above the alternator belt and it would get a few drops (or mist) of tranny fluid on the belt. Especially after adding tranny fluid!

But this was in a GM 3/4 ton van, V8.

A single wire alternator takes more RPM's before charging. You were better off with the older style. Also, the single wire alternator MUST have a very good ground or it won't charge at all. Be sure there's no voltage between the alternator case and engine.

Oh, I see you added a ground strap. To the battery negative or engine? Don't use the vehicle frame.

And are your sure your battery is good? Even if new, check that there is water in it (if it's the type you can check). Once I had a screw on the battery plate that dug into a new battery and leaked all the water / electrolyte out. It took a while for me to figure out that my new battery had a problem! And I have also heard of people buying new bad batteries! Even selling a bad used battery as new by mistake!

Tell me what year it is and I will see if I can find a schematic of its charging circuity if nothing in this message helps.

-Don-[/color][/size]





The Jeep is an '83 Wagoneer Limited. I was building it for a race team I was involved with. Mechanically it's in great shape with no leaks, period. A little dripping from the tranny pan but that doesn't get near the engine. I remembered the problems when these were new and it was usually a bad ground. I have a ground from the block to the battery, a ground from the alternator casing to the engine, two 8 gauge ground cables from the frame to the engine block and the body to battery ground is also good.
The belt is new and dry. The vehicle was charging with the old alternator and I replaced it. It still didn't charge. I put the one wire on in case the problem was in the red and white wires to the regulator. It worked for a while and then quit charging again. I tested it and the alternator was good. Neither alternator will charge. Both have been tested and came back good. The ignition switch on the steering column was giving me problems anyway so I replaced it with no result.
The kicker is the hot wire I added. According to the auto electric shop, with rpm's it ought to charge. I've got maybe $3K in this thing and just don't want to fool with it. I've advertised it for $1K just to get rid of it. The engine failed right after I bought it. I put a good used engine in it and while I had everything apart, I replaced the steering gear assembly, steering damper, water pump, fuel pump, starter, alternator (twice) all the hoses and anything else that looked iffy. I wanted something to carry two passengers and be able to lock my tools up while at the races. Once I had it almost done, the team owner had a heart attack (minor thankfully, he's a good guy) and he disbanded the race team. Now I have a Jeep I have no use for and it won't charge so no one wants to buy it. FEH! :-[

DonTom
02-02-2008, 09:29 PM
"It worked for a while and then quit charging again. "

Sounds exactly like what my belt problem did! But can you check the voltage right out of the alternator while the engine is running? Is there a separate voltage regulator? But let's start to see if the alternator has output while in your vehicle. We will do this one step at a time.

It's best to use an analog voltmeter. A cheap ten dollar one will do. Start with the 50 VDC scale between the alternator's case and the single wire. See what DC voltage you have there when the engine is at a fast idle and then get back to me.

"The belt is new and dry. "

You didn't say tight. Try it with what you think is extra tight for now to make sure there's not even a slight chance of any slippage. Get it as tight as you can, until this testing is done.

"The vehicle was charging with the old alternator and I replaced it. It still didn't charge."

Sounds like you're contradicting yourself there. Can you make that clearer? Did it charge or not with the old alternator? And if so, why did you replace it?

If you're in the SF Bay area, I will be happy to look at it for you. Sounds like a simple problem. There's really not much to the charging in a vehicle.

Also, this is important. Does the vehicle have an idiot light to show when the alternator fails? If it does, is the lamp good? Does it turn on when the ignition is on but engine NOT running but turn out when the engine is running? If that lamp burns out, you have NO charging in MOST vehicles.

The lamp is a better troubleshooting tool than the voltmeter in most vehicles of the 1980's. In fact, in my RV and Van, I added a lamp because they both only had voltmeters. That way I will know the very second when the belt breaks or have a charging problem, unlike the voltmeter that very slowly goes down when there's a problem.

Most vehicles of the 1980's that have a charging lamp use that lamp as part of the charging circuit. If the lamp does not light when you turn the ignition on (before starting engine) you KNOW it won't charge when the engine is started, even if the only problem is only a blown out (or missing) charging indicator bulb.

-Don-

grouch
02-02-2008, 11:17 PM
[

It's best to use an analog voltmeter. A cheap ten dollar one will do. Start with the 50 VDC scale between the alternator's case and the single wire. See what DC voltage you have there when the engine is at a fast idle and then get back to me.[/color]


"The vehicle was charging with the old alternator and I replaced it. It still didn't charge."

[color=blue]Sounds like you're contradicting yourself there. Can you make that clearer? Did it charge or not with the old alternator? And if so, why did you replace it?

If you're in the SF Bay area, I will be happy to look at it for you. Sounds like a simple problem. There's really not much to the charging in a vehicle.

Also, this is important. Does the vehicle have an idiot light to show when the alternator fails? If it does, is the lamp good? Does it turn on when the ignition is on but engine NOT running but turn out when the engine is running? If that lamp burns out, you have NO charging in MOST vehicles.


I pulled the old alternator when it quit working. I don't usually fix what's working, unless it looks like it's about to fail. I'm nowhere near the S.F. area. I'm in S.W. Indiana where Indiana gives Illinois and Kentucky a wedgie. The Jeep has a factory ampmeter but it was bypassed in favor of an after market one. I slapped the alternator back on to drive the Jeep next to the garage. Once the weather breaks for good and I get caught up on some other stuff, I plan to follow the wires and see what is in what kind of shape. I'm pretty sure when I find the fault, it'll be something simple.

DonTom
02-02-2008, 11:34 PM
"The Jeep has a factory ampmeter but it was bypassed in favor of an after market one."

What does the ampmeter show when you have the engine running with the new alternator? The ampmeter has to work for it to charge, unlike a voltmeter. I assume the needle stays to the left and no change (showing discharge) with the ignition on not running and the same when compared to the engine running. Is this correct?

-Don-

grouch
02-03-2008, 09:06 AM
"The Jeep has a factory ampmeter but it was bypassed in favor of an after market one."

What does the ampmeter show when you have the engine running with the new alternator? The ampmeter has to work for it to charge, unlike a voltmeter. I assume the needle stays to the left and no change (showing discharge) with the ignition on not running and the same when compared to the engine running. Is this correct?

-Don-





It shows neutral at rest and discharge when running. Turning on lights makes it discharge more. The more load, the more it moves to the left. I bypassed it and it still didn't charge so I'm pretty sure it isn't the gauge. The charge/no charge started with no warning. I don't rely on just one meter. I used two different volt/ohm meters and both show the same reading.

DonTom
02-03-2008, 10:00 AM
"I used two different volt/ohm meters and both show the same reading."

What DC voltage do you have on the single wire on the alternator? Running and also ignition on not running?

I never expected the ampmeter as being your problem. I just wanted to make sure it was giving some indication of what's happening. Is there any difference at all shown on the ampmeter when the engine is running and not running (ignition on -- with same load each time)?

You should have DC voltage on the single alternator wire with the ignition on, even with engine not running. It should increase when the engine is running at fast idle.

Does it or not?
-Don-

chiph
02-03-2008, 12:32 PM
When you turn the key to the run position, what does the ampmeter say?
It should show a slight discharge (from the power needed to run the ECU, etc). It should not be all the way into the "discharge" zone.

(I'm thinking there's something drawing a large amount of current)

Chip H.

DonTom
02-03-2008, 06:32 PM
"I'm thinking there's something drawing a large amount of current)"

I remember Tom's 1974 Dodge had an ampmeter. It showed quite a discharge when not charging.

But that was one reason why I asked grouch about any change between engine off (ignition on) and running.

If he has that bad of a short to the point of no charging, something must be getting very hot. And would probably be blowing out alternators. And since he can see a difference when the lights are on, I doubt if it's a short. I would think the meter would be pinned to the left if he had that bad of a short.

-Don-

grouch
02-03-2008, 06:44 PM
It depends on the state of charge of the battery what voltage I get. When turning on the ignition, there is a slight discharge condition. I get good readings only slightly lower than the battery reading through the wires. My concern is if there is resistance somewhere in the circuit and while the voltage is there, the amperage isn't. I found some really iffy connections when I pulled all the looks off the wires. When the weather breaks, I may go over them all and redo them. Duct tape is NOT electrical tape. Currently, the Jeep is sitting next to the garage with the battery unhooked to avoid a fire. I did have a couple of times with a dead battery when I had a good battery in there. That was one reason I replaced the ignition switch on the steering column. Odd things would sometimes happen. I haven't driven it much since replacing the switch since it doesn't charge. Either now or before the switch replacement. I really just want to sell this puppy and get rid of it. On the other hand, except for the charging, it's a solid running vehicle.

DonTom
02-03-2008, 09:55 PM
"I get good readings only slightly lower than the battery reading through the wires."

Are you checking the voltage right at the alternator on the single wire right where it goes into the alternator (engine running & not running)? Black negative voltmeter lead on engine. Use 25 or 50 VDC scale on a cheap analog meter (VOM).


-Don-

DonTom
02-04-2008, 12:44 AM
Grouch,

Are you familiar with fusible links? That's one reason I want to know the voltage on the alternator wire. Within an inch of where it connects in the alternator, if possible.

A fusible link is simply a wire that's thinner and is used as a fuse where fuses should not be used. Commonly used on ignition stuff. Usually less than six inches long.
-Don-

grouch
02-04-2008, 07:35 PM
"I get good readings only slightly lower than the battery reading through the wires."

Are you checking the voltage right at the alternator on the single wire right where it goes into the alternator (engine running & not running)? Black negative voltmeter lead on engine. Use 25 or 50 VDC scale on a cheap analog meter (VOM).


-Don-





I tested the voltage at the alternaotr hot rie, the battery positive terminal, the solenoid hot connection and at the wire from inside the Jeep. There is usually a minor voltage drop but nothing major. I'm quite a familiar with fusable links. That's the first thing I looked for. the Jeep is beside the garage out of the way. It isn't eating anything so it'll just sit until I either sell it or feel like fooling with it again. That 360 engine and 3.55 gears means it will really tow a trailer.

DonTom
02-05-2008, 12:21 AM
" I tested the voltage at the alternator hot rie, the battery positive terminal, the solenoid hot connection and at the wire from inside the Jeep. There is usually a minor voltage drop but nothing major."

If the alternator passes the bench testing yet has normal voltage going to it while in the vehicle and it has a good ground, leaves NOTHING left other than (save from a dead short which would pin your vehicle's amp meter to the left and you would then notice no difference when the lights are turned on) :

1. The alternator is NOW blown out. IOW, blew out after the bench test.

2. It's slipping (belt problem).

3. At least one shorted cell in battery (but would then measure less than 10.5 VDC across battery).

There are no other possible differences between a bench test of the alternator and the alternator being in your car.

Another indication of it NOT being a short is having the normal voltage to the alternator when the engine is not running.

-Don-