Chonic Alternator Failure

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/6 Matt

/6 Matt

30 Degrees Crooked
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So the car is a '70 Dart with a slant six and a 65 amp alternator.

The problem, I've been through 4 alternators and voltage regulators in the past 9 months. Every few months the car gets to the point where it discharges on idle with the headlights and/or the HVAC blower motor running. It acts almost like the alternator keeps dropping a field or two, I don't know if that's what's going on or not cause I don't have access to a oscilloscope to actually see what's going on after failure. Whenever I suspect failure, I bring it to Autozone and they put it on there test machine and it always fails. Same goes for the voltage regulator. I get a new Alternator and VR under warranty and two to three months later its the same thing.

Are duralast parts really this crappy? Or is there something else going on here? Anyone got any ideas on some things to check out before I replace the current alternator and VR?
 
Have you had your battery tested?
 
have battery tested, check main battery wire at alternator for voltage, check ammeter in dash for failure
 
RustyRatRod said:
Have you had your battery tested?
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No but I know its a little weak.

66plyValiant said:
have battery tested, check main battery wire at alternator for voltage, check ammeter in dash for failure
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I know while running the voltage at battery should be above 12.6 and under 14.5 volts, what about the main battery wire at the alternator? Same or .2 volts higher? The ammeter works, does that rule that out or is there a test to run to determine failure?
 
If the battery is weak, it is probably making the alternator charge more than normal and that is where the problem is.
 
What do you run to monitor the system, IE ammeter / voltmeter?

If ammeter, does it ever center at zero, just cruisin' down the road?

If voltmeter, and make sure it's ACCURATE what does it run for voltage

And as above, let's just "say."


"Say" you have one cell has a problem, I've seen these turned the engine over surprisingly well. But the alternator was always trying to charge it, so the alternator ran hot and was always "working."
 
I had a 69 Valiant 273 that would "eat' alternators and regulators also. While driving down the road, the amp gauge would sometimes "flick" to discharge, then charge.

I finally found the problem was the wiring under the dash had been overheated and melted a bunch of them together and a few wires were bare and grounding against the dash frame. Got the wiring diagrams out and re spliced all the bad wires and went through all the wires to the alternator and regulator underhood. That was the last alternator and regulator that I bought. the sporadic grounding was killing the electrical system. Once fixed, it was fine.


Watch your ammeter for it going to discharge and if it does check your wires under the dash.
 
Frankly I think the problem is the Vatozone parts. Find you local starter/generator/alt. shop that does OTR, industrial, marine, and/or farm equipment work. Get parts from them and see how long they last.
 
ntsqd said:
Frankly I think the problem is the Vatozone parts. Find you local starter/generator/alt. shop that does OTR, industrial, marine, and/or farm equipment work. Get parts from them and see how long they last.
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Sorry but even as bad as present parts are, I REALLY doubt this is the problem
 
67Dart273 said:
Sorry but even as bad as present parts are, I REALLY doubt this is the problem
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I really doubt that it isn't part of the problem. Been burnt by them enough times to give them NO credit with reman electrical parts. None.

Yeah, burnt wires under the dash would be the first thing that I'd investigate. Then I'd wire around the ammeter so that it and the firewall connectors aren't a fire hazard. Check/replace the battery. If all of that is good, quit wasting time with the big chain stores and go to someone who knows wtf they're doing.
 
The ammeter is always centered except for a few moments after starting or during times of idle in gear with a load on the electrical system. No jumps or any indication of any issues outside the issue that the alternator has failed and doesnt put out enough on idle.
 
ntsqd said:
I really doubt that it isn't part of the problem. Been burnt by them enough times to give them NO credit with reman electrical parts. None.

Yeah, burnt wires under the dash would be the first thing that I'd investigate. Then I'd wire around the ammeter so that it and the firewall connectors aren't a fire hazard. Check/replace the battery. If all of that is good, quit wasting time with the big chain stores and go to someone who knows wtf they're doing.
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I like my ammeter. Id rather not get rid of it. Ammeters tell you way more about your charging system than a voltmeter ever will.
 
I disagree. All an ammeter can tell you is if charging or discharging and generally by how much. A voltmeter will tell all of that and the condition of the battery as well.

But that is neither here nor there, you asked for advice and I gave you mine based on my prior experience. You're not obligated to take it. I'm not obligated to continue giving it either.

If you want to keep the ammeter then don't wire around it. All of what else I've said still stands.
 
ntsqd said:
I disagree. All an ammeter can tell you is if charging or discharging and generally by how much. A voltmeter will tell all of that and the condition of the battery as well.

But that is neither here nor there, you asked for advice and I gave you mine based on my prior experience. You're not obligated to take it. I'm not obligated to continue giving it either.

If you want to keep the ammeter then don't wire around it. All of what else I've said still stands.
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lol
 
ntsqd said:
I disagree. All an ammeter can tell you is if charging or discharging and generally by how much. A voltmeter will tell all of that and the condition of the battery as well..
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A voltmeter tells you nothing of the condition of the battery, unless it's measured with system OFF and in between engine runs long enough to dissipate surface charge. Most factory or even stuff like Autometer is not nearly accurate enough for really definitive readings.

An (good) ammeter is an EXTREMELY useful tool. An ammeter that does not run "centered" when under light load and cruising tells you a BUNCH

If it's not centered, it might be that due to system problems, the charging voltage is too high, IE "it always wants to charge."

The same indication can suggest the battery has a problem, IE sulphated

While a voltmeter OVER TIME will drop some under load, this is not always immediately apparrent. But an alternator that cannot keep up will IMMEDIATELY indicate a "left of center" view on the ammeter.

I grew up with ammeters. I still to this day would prefer a "good" one.

Unfortunately, they don't exist. When "everybody" went to remote shuts, which in real actual terms means "we all got C.S. and used the wiring harness for a shunt", many of these became so "numb" as to be completely useless. The 86 Ranger I just sold was so "numb" that if you switched on the headlights, engine off, you STILL had to stare intently at the needle to figure out if "it really moved."
 
/6 Matt,
Search for my post on how to use parallel diodes to bypass the ammeter at high current, when needed, yet keep if functioning at normal currents. You sound sharp enough to follow it.

I suggest you get a voltmeter that plugs in the cigarette lighter. Harbor Freight has one w/ LED's for $4 on sale, though one I have lost a few LED's. I have a better $15 digital display one (Amazon Eqquis). I use them in all my cars. Indeed, in my modern cars you are flying blind without one. Should read about 12.6 V w/ engine off (ign on) and 14.3 V w/ engine running.

If you have a large drop thru the bulkhead connector or "ALT welded junction" under the dash, your Vreg will make the alternator put out too much current. Both are common corrosion areas. The ALT junction was pretty green in my CA Dart and much wetter where you live.
 
I usually put the triple gauge kit with the voltmeter, oil pressure, and mechanical temp gauge. This way I run both a voltmeter and stock ammeter. Then you know more of what is going on in the electrical system..
 
something is shorting somewhere... or spiking the alternator.

1. make sure everything is properly grounded. (alternator included, VR, engine block grounds to firewall, etc.)

2. it could be your blower motor or A/C components... even headlights.

3. check the entire system for bare wires touching ground, or corroded/tarnished connections. a tiny piece of emery cloth on connectors can do wonders.

4. headlight harness is a likely candidate also. it's very likely that the connectors need maintenance badly. again clean all of those connectors as best as you can.
 
I've seen starters go bad and draw current.
I've seen battery lead to starter worn to intermittent and small draw ( most common w/ headers ).
I've seen starter relays go bad and leak just enough current to slowly heat the starter rather than run it.
Now for my take on amp versus volt gauge... Any gauge on any system should be like a news reporter. Just show/tell what's going on. The reporter should not interfere with the story he is reporting. Failure of Chryslers ALT' gauge can shut down the car. Equal to Clark Kent in the dash in my opinion. This mind set is my main reason for converting to a volts gauge.
 
Bear with me folks, my only two days off this week has left me pelted with rain so I haven't been able to check anything out with the car. :banghead:
 
Lots of good info here and some not so good. Matt, all I can recommend is listen to Del.
 
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