Help, car keeps dieing

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akehurst89

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I have a 1970 dart swinger with a 340. I took it out for a ride and started fine all day. Stopped for a bite to eat and notice when I went back out to start it it started slow. So I drove to a friends house about 15mins away and shut it off for about 5mins and went to start it again and it would hardly turn over and drained the battery. So I jump started the car and drove it 5mins down the road and it died. The tac quiet working, ans turn sognal indicators in the car stopped workif .and I noticed the alt gauge never goes to charge is stays just in front of the discharge side. So would that be a bad alternator or voltage regulator?
 
If you haven't already, check the belt tension, then charge the battery and have it checked. Look for loose connections and bad grounds, and other wiring problems. Then go on from there.
 
Check the belts and leads and grounds. Everything looks good there. The battery is a brand new optima red top.
 
Try wiggling the bulkhead plug (the plugs with numerous wires that pass through the firewall. I've seen lots of electrical issues there. If that checks out ok and your reasonably certain there's no electrical connection problem all that's left is the alternator and regulator and either will cause your problem and there's really no way to say for sure which one it is but the easiest thing to do is take the regulator off and take it to your local auto supply and have them test it. Nowadays almost all auto supply stores have a tester. If the regulator tests good the next thing to do is have the alternator tested.
 
Nowadays almost all auto supply stores have a tester. If the regulator tests good the next thing to do is have the alternator tested.
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Save a trip, take both regulator and alternator in for a test. If they check out, reassess wiring & connections.
 
The trouble with so called "testers" is that

1--They only show if something is bad, not good, and are only reliable if they are "honest" and the operator knows what he or she is doing

2--No typical parts store alternator tester can test an alternator under full output load. This means there is no way of knowing whether your 40, 50, 60A unit can actually output it's full rating.

In other words, these testers are fine as far as they go. They are not absolute
 
67Dart273 said:
The trouble with so called "testers" is that

1--They only show if something is bad, not good, and are only reliable if they are "honest" and the operator knows what he or she is doing

2--No typical parts store alternator tester can test an alternator under full output load. This means there is no way of knowing whether your 40, 50, 60A unit can actually output it's full rating.

In other words, these testers are fine as far as they go. They are not absolute
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I understand they don't load the alternator to test for full output but his description makes it sound like it's not charging whatsoever. Agreed that a tester is only as good as the operator but I have yet to run into a case where they told me something was bad or good when it wasn't. Had a couple times where they couldn't get it to test (problem with the tester) but they told me. I suppose it's possible some unscrupulous person could lie about the outcome. So far I haven't ran into that.

Since you don't trust having them tested what's your method for determining what the problem is?

70 would be a dual field circuit, correct? If that's the case I think to test the alternator for output one of the field wires needs to be ran to B+ and the other to ground. If it charges "hotwired" that tells you the alternator is good and the problem is elsewhere. Is that correct?
 
akehurst89 said:
I have a 1970 dart swinger with a 340. I took it out for a ride and started fine all day. Stopped for a bite to eat and notice when I went back out to start it it started slow. So I drove to a friends house about 15mins away and shut it off for about 5mins and went to start it again and it would hardly turn over and drained the battery. So I jump started the car and drove it 5mins down the road and it died. The tac quiet working, ans turn sognal indicators in the car stopped workif .and I noticed the alt gauge never goes to charge is stays just in front of the discharge side. So would that be a bad alternator or voltage regulator?
Click to expand...

My Duster is doing exactly the same thing. We even have the same battery. Haven't had a chance to troubleshoot yet but was given some advice in another thread that I am going to follow. Look for the thread in this section called Crap, had the car 3 weeks.... Might help you too.

Steve
 
If you have access to a volt meter, measure the battery voltage (should be at least 12 volts) then start the car, the alternator should be putting out around 13 volts. If there is no change after you start it the alternator isn't putting out any voltage. The regulator could be bad or the alternator could be bad. See if you have voltage at the field terminal (the small spade connector) of the alternator. If you have voltage I would suspect the alternator, if not I would try a voltage regulator.

Good Luck,
 
fishy68 said:
Since you don't trust having them tested what's your method for determining what the problem is?

70 would be a dual field circuit, correct? If that's the case I think to test the alternator for output one of the field wires needs to be ran to B+ and the other to ground. If it charges "hotwired" that tells you the alternator is good and the problem is elsewhere. Is that correct?
Click to expand...

You can easily learn to test them "on the car," and surely you've read some of my posts.

There are several areas you need to check, assuming factory wiring

1--You need to determine if the alternator output is actually hooked to the battery, IE problems in the bulkhead connector / ammeter circuit on the way to the battery

2--You need to determine if you have a field circuit wiring problem, easily done in the course of tests

3--Determine if the alternator can and will charge by bypassing the regulator and in fact the harness wiring, as in the case of the 70/ later system, it might not be getting field power from the blue field wire

4--If the alternator can be made to charge by bypassing the regulator, then you "add in" the harness, until, finally, the only component you've eliminated is the regulator.

5--Make certain that the regulator was actually grounded, and everything above is good, replace the regulator.

All of the above only takes a few minutes once you learn how. When / if you DO replace an alternator/ regulator after on--vehicle testing, this is no longer pretty much "throwing parts" at the problem, because there is now an almost certainty that you have found the problem.

Of course if you don't mind having a stack of spare parts, or if you DO have, and it's quicker just to "throw" a new alternator/ regulator on the car, then that's OK too.

But what...........do you do...........if...........in that stack of spare parts, it turns out that both your spare alternators are actually BAD? This means you've just changed one or two alternators, and STILL don't know what the problem really IS?

Or...........what happens..........(and it has!!!) if either the "parts guy" doesn't know how to use "the tester" or the tester is just plain broke? He tested the (good) alternator as "bad" so that's what you buy, you drive ALL the freekin' way home, and replace the thing, and ..........well you know.............
 
Get a cigarette lighter voltmeter. I got several for $3 on sale at HF and put in all my modern cars that have poor charging diagnostics. I especially use them on long trips so I don't get surprised by a no charge situation. You should read ~12.6 V off and ~14.3 V when running, if the alternator works.

I also have a Black & Decker battery charger that has an "ALT Test" function. It just looks for sinusoidal fluctuations that are typical of the alternator output. It was cheap at Big Lots, and is small and light.
 
67Dart273 said:
You can easily learn to test them "on the car," and surely you've read some of my posts.

There are several areas you need to check, assuming factory wiring

1--You need to determine if the alternator output is actually hooked to the battery, IE problems in the bulkhead connector / ammeter circuit on the way to the battery

2--You need to determine if you have a field circuit wiring problem, easily done in the course of tests

3--Determine if the alternator can and will charge by bypassing the regulator and in fact the harness wiring, as in the case of the 70/ later system, it might not be getting field power from the blue field wire

4--If the alternator can be made to charge by bypassing the regulator, then you "add in" the harness, until, finally, the only component you've eliminated is the regulator.

5--Make certain that the regulator was actually grounded, and everything above is good, replace the regulator.

All of the above only takes a few minutes once you learn how. When / if you DO replace an alternator/ regulator after on--vehicle testing, this is no longer pretty much "throwing parts" at the problem, because there is now an almost certainty that you have found the problem.

Of course if you don't mind having a stack of spare parts, or if you DO have, and it's quicker just to "throw" a new alternator/ regulator on the car, then that's OK too.

But what...........do you do...........if...........in that stack of spare parts, it turns out that both your spare alternators are actually BAD? This means you've just changed one or two alternators, and STILL don't know what the problem really IS?

Or...........what happens..........(and it has!!!) if either the "parts guy" doesn't know how to use "the tester" or the tester is just plain broke? He tested the (good) alternator as "bad" so that's what you buy, you drive ALL the freekin' way home, and replace the thing, and ..........well you know.............
Click to expand...

Actually I haven't read very many of your electrical posts but I do know how to diagnose a charging problem just as you described. When I worked for Hyster electrical problems was my specialty. Only thing is I'm a hands on person, not always good at putting things in writing. For that reason I figured it'd be easier to poke you and get you to write it up cause your a better writer. Hope you don't mind Del
 
superchargeddrt said:
If you have access to a volt meter, measure the battery voltage (should be at least 12 volts) then start the car, the alternator should be putting out around 13 volts. If there is no change after you start it the alternator isn't putting out any voltage. The regulator could be bad or the alternator could be bad. See if you have voltage at the field terminal (the small spade connector) of the alternator. If you have voltage I would suspect the alternator, if not I would try a voltage regulator.

Good Luck,
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Actually the battery voltage should be a very minimum of 12.6 volts when the car isn't running because each cell is 2.1 volts (2.1 x 6 cells=12.6 volts) and charging should be right at 14 volts when the battery is fully charged. And I believe a 70 will have a dual field alternator. With that in mind the voltage on one field should read battery voltage and the other should read a low voltage that varies depending on what the regulator is putting out as it's a controlled ground. Your method of checking is correct for a single field alternator like used in pre 70 vehicles.
 
Took the alt out of car to get tested. Once I get the voltage regulator and alt tested I will let u guys know from there. Hopeing it is one of those two and not some pain wiring problem in the bulkhead.
 
Another question if you test the alt in the car with a volt meter if its not putting out the right amount of volts does that narrow it down to the alternator being bad or is there still a possibility the regulator could have somthing to do with it.
 
The "quick test.............."

Pull the green wire off the alternator field (one field is blue, one is green) and ground the terminal on the alternator you just disconnected. Start it, watch the ammeter and bring up RPM It should charge more and more as RPM increases.

If this does NOT happen, put your voltmeter directly onto the alternator output stud to ground. Measure voltage with engine running. If voltage is way high, you have a problem in the charging line. If voltage is low, "same as battery," around 12 --below 13 volts, alternator is not charging.

If that happens, check the harness. To do that, pull the blue field wire off and ground that alternator terminal. Hook the green wire back up. Pull the connector off the regulator and devise a way (screws, etc) to jumper the two terminals on the regulator harness plug. Repeat the test. If the alternator charges significantly in both tests,.............

then work the connector in/ out several times on the regulator and inspect for corrosion, and "feel" for tightness. Try to have someone watch the ammeter, engine running, as you wiggle the connector. Also make absolutely sure the regulator case is grounded.

If this does not restore operation, replace the regulator.
 
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