Hi everybody.

Maybe three months ago I rebuilded the alternator due to it went broken and my battery gets discharged. Today on the way to home from work the headlights were very faint (but if I rev the engine them comes brighter) and the dash backlight too and a few minutes ago the battery gets discharged again fortunately while i was parking. What can be wrong now? in all the way to home the alternator gauge was on -30 position while the car was idling, when the car was running it goes to 0 position or sometimes a bit near to +30 position

Here's how the HEI ignition is wired:

 

Maybe the rebuilt alt is junk. What all did you replace in it?

 

I don't know, My mechanic did it, but I'm starting to believe that my mechanic sucks so I'm going to take the car to another guy to inspect it

 

That wiring diagram can't be right, where did it come from?

 

I added the relay to get a constant 12V power supply to the HEI distributor and I haven't problems with this and the car idles very smooth. I think the problem is going to be the alternator, a hour ago I rev the engine with the headlights off and the alternator gauge barely moves so I think the charge isn't enough to keep the battery charged.

Maybe tomorrow the new mechanic will be able to remove the relay and found a constant 12V power supply

 

It looks like you've got one of the alt fields powering your ignition relay and perhaps other things.

 

Some minutes ago I left the car with the new mechanic, he said to me that the relay system isn't affecting the alternator charge but is a electrical failure symptom because the car has to be able to keep a constant 12V - 14.5V even with the headlights or accesories working, he checked the battery charge and the diagnostic is that the car is overloading the battery (while the engine is revving the incoming battery voltage goes from 12V to 19V). I must call him in the afternoon to know what is wrong with the car.

I will be discussing the latest news, thank you!

 

That is wired just fine, IF it is wired as per t he diagram Your mechanic is deficient in troubleshooting.

These systems are amoung the easiest there are to troubleshoot. Point numba whon: The regulator MUST be grounded, and grounded to "same as" battery. Scrape the firewall clean, scrape the mounting flange clean, and use star lock washers. If necessary, increase the size of the jumper(s) from the block / firewall / battery. ALL THREE must be grounded together It sounds like it is not charging or barely "trying" to put out.

There are several "areas" of the system

1...Belt slippage. Sounds elementary. Well, it is, but "polished" that is, glazed belts and pulleys, or wet ones, can drive you nuts. Check belt tension

2...Field circuit. In your case it sounds as if it's "trying" to charge. Poor brush condition, poor spring tension, grease / dirt/ debri causing brushes to stick, or bad surfaces on slip rings Poor field circuit connections, IE regulator ground, corroded/ loose connector at regulator, or wiring in general. Bad regulator

3....Problems in alternator, IE bad diodes, bad stator, etc

4...Loose/ bad connections in the OUTPUT circuit, this is the line from the battery. Since I don't know, ........you still using the factory bulkhead connectors and ammeter? -------------------------------------------------------------------------------------------------------------------------

Troubleshooting

Here's how this works. The blue field wire supplies power to the field, and the regulator controls the "amount of ground" to the field.

So, disconnect the green wire at the alternator and clip a grounding lead to the exposed alternator field terminal. This will "full field" the alternator. With the engine running "fast" it should bury the ammeter on the charge (right) side

If not, determine if you have voltage at the blue, and if the field is drawing current. With key in run, but engine off, and your clip lead connected, measure voltage at the blue field terminal. You should have "same as battery." If so, Determine if field is drawing current.

If you have a multimeter which will measure a few amps (10A or 20A DC scale) Hook the meter in place of your clip lead to ground. Key in run, the field should draw (various years) something over 2A maybe as much as 4A. If less, you have a problem. Release the belt and turn the rotor by hand when checking If the above checks out, maybe there's a poor connection in the output (charging line to battery)

Hook up your clip lead to ground, and run the engine fast, to simulate low/ medium cruise RPM Check ammeter, not charging? Check battery voltage, probably somewhat low, below 12.6 Now check voltage directly at the alternator output stud. If this voltage is quite high, over 16V or so, you have a bad connection in the output. If the voltage is quite low, 12-13V, then the alternator is just plain not outputting because if it were, the ammeter should be "buried."


Along with the above, examine the regulator terminals and connector for corrosion. "Work" the connector in/ out several times to scrub the terminals and to "feel" for tightness.

If the alternator outputs good in the above tests, check the regulator wiring.

To do that, "rig" a jumper across the two regulator terminals, that is, from green to blue. Now go down to the regulator, hook your green wire back up, and this time, remove the blue field wire, and ground that alternator terminal. Once again, running fast, alternator should bury gauge to right. If so, replace the regulator. If not, either alternator still has a problem, or you have problems in the regulator field wiring.

 

The relay wiring if as shown is not the problem. It is simply powering the ignition system. Frankly, I would run the regulator / field circuit off a relay AND DO SO

 

The new mechanic said that this is the right way, but first must find the electrical failure reason.

A moment ago the mechanic called me and said that the voltage regulator is broken and two alternator diodes has blown so is going to check the entire alternator, clean it and if it find more problems he will notify me.

Yes, the car has the stock battery line and bulkheads

 

Now the car is fine, the mechanic replaced the regulator, did a general maintenance to alternator and fusebox and change the blown diodes, replaced the battery line and bulkheads, the best part is that right now the car is running without the relay sistem and apparently is running well

 

Frankly, I find his explanation a bit on the unbelievable side.

These particular systems rarely blow up both a regulator AND alternator diodes, unless.......

Was the thing operated for a considerable period and terribly OVER charging? This would have been obvious, the ammeter pegged or nearly so, the battery hot, sticking, and puking acid all over the battery compartment.

WHAT I BELIEVE happened:

Your mechanic "threw" a regulator at the problem and this did not fix it, THEN he found out the alternator was bad.

You are not talking, here to a new guy. I bought my first Mopar in 1970, and had been driving several years before that. I have a VERY good understanding of how these works, and the failure mode.

To put this bluntly, I find your mechanic is "full of crap."

 

Well... I think that you have the entire reason because the problem continues, the car takes more time to shut down when the headlights are on but it continues stoping so I'm going to reinstall the relay tomorrow.

About the overload the car ran about six days overloading the battery and the battery compartment has traces of battery acid.

The mechanic is going to check again the car as a service warranty the next week, but fortunately now the battery is getting good charge and the alternator gauge always stays on neutral position or +30 position, never in -30

What can be the problem? this mechanic check all the car grounds and are fine and now the alternator is working well. I don't know if matters but he gave me the old regulator

 

There are several areas in these systems, that cause problems.

GROUND. The regulator CASE absolutely MUST be at the same voltage as the battery neg. In most cars / front battery, the battery main ground is to the block, with a smaller ground(s) either from block to body or from battery to body.

This can only be checked on a system that is charging somewhat normally. You are looking for "voltage drop." With the engine running fast, check first with all accessories off, and again with heater , lights, etc on. Stick one probe of a meter onto the battery NEG post, and the other probe directly onto the mounting flange of the regulator. You are looking for a very LOW voltage, the LOWER the BETTER, and zero is perfect. Anything above .2--.3V (three tenths of one volt) means the grounding is poor.

HARNESS VOLTAGE DROP

Same idea. The regulator MUST see "same as battery" voltage. Refer to your diagram above. Closest (electrically) "handy" place to get at the regulator voltage is at the blue field wire on the alternator.

To check this, turn key to run, but with engine off. Put one meter probe on the alternator blue field terminal, the other probe on the battery POS terminal. Don't unhook anything, rather probe this with all connections in place

Again, with grounds, you are hoping for a very low voltage. Over .3V means you have a bad connection somewhere. The current path in a factory car is

Starter relay stud.....fuse link.....bulkhead connector.....ammeter......"in harness splice".......ignition switch connector....through the switch....back out the connector (on ignition dark blue).....back out bulkhead connector......to underhood loads.

In the above path, there are several ways for error. Since you have a relay, hook the alternator field and regulator IGN terminal to run off the relay. If the relay is properly set up, this should reduce voltage drop

Don't forget.......could be a bad connector right at the regulator

Alternators should be easy to check. You can eliminate ALL field wiring by substitution. To get the thing to output 100% for test, you simply ground either field terminal, and feed 12V into the remaining field.

With the field hooked solidly to battery power, run the engine fast. Check battery voltage and alternator output stud voltage. If there is more than about 1 1/2 to 2 volts difference, you have a wiring problem in the output line

READ this article

http://www.madelectrical.com/electri...p-gauges.shtml

That article points up the main problems of these cars starting about 65 or so. The main problems are:

Generally too small wiring

Big big problems in the bulkhead connector, in the black charging lead, the red battery feed, and the ignition feed coming from the ignition switch. and.........headlights

Probably the worst problems are:

Bad connections in the bulkhead black and red connectors

Bad connections at the ammeter

Problems in the ammeter itself

Bad connections at the ignition switch connector

Voltage drop in the ignition switch

In rare instances, failure of the "in harness splice." Look at the MAD article. The "in harness splice" is a welded factory electrical splice in the under dash harness, in the black ammeter wire, a few inches from the ammeter. It branches off and feeds the light switch, the ignition switch, the fuse "hot" buss, and a couple of other things.


After you get done chasing your tail........keep this in the back. IT IS possible that the battery itself has a problem. If you get to where it seems to be working half normally, and you've checked everything else, BUT WILL NOT run the correct voltage, try another battery. This does not have to be a NEW battery, just a known good one, temporary, out of another car.

Since you are still running the ammeter, I would SERIOUSLY consider performing the MAD bypass. If you ABSOLUTELY do not want to do that, at LEAST check some of this stuff, and repair the bulkhead connector, or bypass it.

 

Thank you for this great explanation . I'm going to check all the recommendations you listed but I just remembered that my car ammeter isn't working so I installed an aftermarket alternator gauge. Can this be a symptom of a failure?

When finished reviewing I'm going to post the results.

 

Without knowing how you re-wired things anything is on the table.

That is why at some point you should, as I said earlier, check running...charging battery voltage AFTER you get the field/ regulator fixed if possible, and check battery post voltage against alternator output stud voltage. IF the alternator stud is more than 1 or 2 volts above battery WHEN CHARGING this shows you have resistance in the "charging line." So, EXAMPLE, if your second ammeter is bad, IE poor connection, you'll have more of a difference of voltage between the two.