SputnikOne
Well-Known Member
Here's the rest
73 Dart Alternator doesn't show charge anymore.
- Thread starter SputnikOne
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SputnikOne
Well-Known Member
This connector specifically is concerning, anyone know where it goes? It's a red wire by the brake booster
That wire looks like hell. Why no voltmeter? You can buy them at ANY hardware store, Lowe's or Home Depot. Just about any auto parts store that has the gall to gall itself one will have them.
You can get a decent but cheap Klein for 15-20 bucks. While you are there, "somewhere" get into the electrical connections and find either a few alligator clips or some alligator jumper wire leads.
I don't recommend Horrid Freight but they have that stuff, as well
You can get a decent but cheap Klein for 15-20 bucks. While you are there, "somewhere" get into the electrical connections and find either a few alligator clips or some alligator jumper wire leads.
I don't recommend Horrid Freight but they have that stuff, as well
SputnikOne
Well-Known Member
Just grabbed a voltmeter, had to work yesterday but I'll see what I can see this morning.
SputnikOne
Well-Known Member
Battery has 12 volts still according to the voltmeter, will start it soon to see if it charges
SputnikOne
Well-Known Member
Battery voltage didn't change with the car running, just the slight discharge from the battery. Put both leads of the voltmeter on the black wire terminal on the alternator and wasn't seeing any voltage.
SputnikOne
Well-Known Member
I have continuity touching the alternator output to the battery positive termimal
Generally, don't fiddle with continuity. You are dealing with high amperage, low resistance, and meters get less and less accurate as amperage in the circuit, and wire size increases, and as expected resistance decreases.
Disconnect the green at the alternator and use an alligator clip jumper to ground that alternator terminal. Start and watch battery voltage and your ammeter. Charge should come up. Do not let the voltmeter go above about 16 if it charges.
If not, leaving the field terminal grounded, and the key in "run" but with engine stopped, measure from the blue field wire to ground. Do this with the blue still connected. You should have very close to battery voltage.
If that is good but it won't charge, then move your voltmeter to the big output stud on the alternator. Restart, increase RPM a bit and see if the voltage goes up. If so, you have a break in the charge path from the alternator to the battery, and that connection you pictured may be it
If it does not increase, you have an alternator problem. It may be as simple as worn/ dirty brushes.
Disconnect the green at the alternator and use an alligator clip jumper to ground that alternator terminal. Start and watch battery voltage and your ammeter. Charge should come up. Do not let the voltmeter go above about 16 if it charges.
If not, leaving the field terminal grounded, and the key in "run" but with engine stopped, measure from the blue field wire to ground. Do this with the blue still connected. You should have very close to battery voltage.
If that is good but it won't charge, then move your voltmeter to the big output stud on the alternator. Restart, increase RPM a bit and see if the voltage goes up. If so, you have a break in the charge path from the alternator to the battery, and that connection you pictured may be it
If it does not increase, you have an alternator problem. It may be as simple as worn/ dirty brushes.
SputnikOne
Well-Known Member
So, what do you recommend to test the alternator and the VR?
SputnikOne
Well-Known Member
With the car idling testing battery negative to the alternator output Im reading battery voltage on the voltmeter, about 12.2 volts now.
SputnikOne
Well-Known Member
Unplugged and removed VR, cleaned the mounting area and the bolts back to bare, no change, positive battery to alternator output shows very low voltage when idling, is this expected?
SputnikOne
Well-Known Member
Touching alternator output lug to the engine block for ground while it's not running gives me 12.45 volts, which is alittle confusing
SputnikOne
Well-Known Member
Yeah, I think the alternator is outputting 12.45 ish volts, which is pretty low, but it would explain why the battery isn't quite dead yet. Got 12.45 volts when touching output to ground from the alternator, and revving the engine seems to make the ammeter move *the tiniest* amount towards charging.
Mattax
Just the facts, ma'am
OK. Lets start at the beginining.
In your words. I could guess but to help I think its best to know where you're coming from.
Why is this confusing?
In your words. I could guess but to help I think its best to know where you're coming from.
SputnikOne
Well-Known Member
Is the voltage coming from the battery through to the alternator and to the block? I guess I don't understand why there's battery voltage from the alternator to ground if it's not running
Mattax
Just the facts, ma'am
OK. Two points will unconfuse this.
The battery and the alternator output are connected together at all times.
With the engine off we are reading battery voltage throughout the connected wires.
So in the car we have two power supplies that are connected together.
When the alternator is running, it produces power at roughly 14 Volts.
The battery at best has power stored at 12.8 Volts.
Imagine those volts as air pressure or water pressure.
Which one will the air, water or electrons flow from?
The battery and the alternator output are connected together at all times.
With the engine off we are reading battery voltage throughout the connected wires.
So in the car we have two power supplies that are connected together.
When the alternator is running, it produces power at roughly 14 Volts.
The battery at best has power stored at 12.8 Volts.
Imagine those volts as air pressure or water pressure.
Which one will the air, water or electrons flow from?
Mattax
Just the facts, ma'am
Lets take a minute and briefly go over Amps and Volts.
Volts are potential energy. The battery is analagous to a water tower. The water in holding tank at the top supplies pressure throughout the pipes when all the valves are shut off. When we meaure 12.8 Volts at the battery with everything shut off, that is the energy level or pressure stored in the battery.
Amperes are a measurement of flow. The amount of electrons moving. If a valve at the bottom of that water tower is opened, then there is flow.
The ammeter shows how much flow is going from the battery to the main junction, or how much current is flowing into the battery to recharge it.
Go back to the diagrams and see the orange arrows. They show flow.
Volts are potential energy. The battery is analagous to a water tower. The water in holding tank at the top supplies pressure throughout the pipes when all the valves are shut off. When we meaure 12.8 Volts at the battery with everything shut off, that is the energy level or pressure stored in the battery.
Amperes are a measurement of flow. The amount of electrons moving. If a valve at the bottom of that water tower is opened, then there is flow.
The ammeter shows how much flow is going from the battery to the main junction, or how much current is flowing into the battery to recharge it.
Go back to the diagrams and see the orange arrows. They show flow.
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Mattax
Just the facts, ma'am
Key off.
Measuring voltage from any of the main feeds should show battery voltage.
Everything connected to the battery is hot. The wire from the alternator output terminal, the wire to the ignition switch, two or three of the fuses, etc.
Engine running.
Measuring voltage at the alternator output eliminates the possibility that the output wire is disconnected.
Now the question is why?
Since you have a voltmeter, with the key in run, check to see if power is making its way to the field wires. @67Dart273 has suggested a procedure for doing this. Then he has suggested a method of checking the alternator and regulator.
I will only add that 12.45 is pretty low for a battery. I'll again suggest putting the battery on a slow charge. The reason is because a low battery will pull a lot of current when given power at 14 to 15 Volts. Even when the wiring gets cleaned and fixed properly, 20 to 40 amps over a fairly short time (5 to 15 minutes) can cause damage. Also recharging at those rates can deteriorate the battery (cook it).
Mattax
Just the facts, ma'am
Now the tricky part.
Why does the ammeter normally show zero after a few minutes of recharging?
If the alternator is supplying power at 14.5 volts, and the battery is fully charged, then is the battery at 14.5 volts?
My best answer is yes, sort of.
Once the battery is has chemicaly returned to fully charge, then a surface cahrge develops. Immediately after charging, and shutting off the engine, we will find the battery is around 13.5 Volts. That surface charge will go away over time, or if we turn a light on, it will go away quickly.
Why does the ammeter normally show zero after a few minutes of recharging?
If the alternator is supplying power at 14.5 volts, and the battery is fully charged, then is the battery at 14.5 volts?
My best answer is yes, sort of.
Once the battery is has chemicaly returned to fully charge, then a surface cahrge develops. Immediately after charging, and shutting off the engine, we will find the battery is around 13.5 Volts. That surface charge will go away over time, or if we turn a light on, it will go away quickly.
Mattax
Just the facts, ma'am
That's the A1 circuit
It's in poor condition but obviously still working. Put some de-oxit on and wrap it for now. Clean up the battery ternimals too. That will all help reduce resistance.
My guess is the big splice is in the R6 circuit, and that its bypassing the engine connector. So again the engine connector is suspect as to why the alternator is not working.
Based on your location, I'd look for marine electrical supplies as a source of moisture resistance splice connectors and wiring.
SputnikOne
Well-Known Member
What big splice? I'm not sure I see what you're talking about, you think it's bypassed on the power cable but the field cables are messed up?
Mattax
Just the facts, ma'am
Mattax
Just the facts, ma'am
The engine connector is a common problem location. You can take advantage of it for diagnosis but its main function according to @RedFish was to make production easier. Earlier cars don't have it.
Anyway, its worth checking to see the condition of the wires and terminals.
Do the steps as I laid them out. This will test the alternator. Once that is known to work, that shows the blue wire TO the alternator (the field power supply) and the alternator itself works, along with the charge path back to the battery.
THEN check the VR wiring out
If the test I laid out shows a charge, hook everything up as normal. Then pull the VR connector and ground the green with engine running on fast idle, and your meter on the battery. With the green grounded, the voltage should go up, depending on RPM. Measure the blue wire in that connector to ground, should show battery voltage
Examine the connector, and the pins on the VR. Push/ pull the connector on/ off the VR several times, to "scrub" the terminals and to 'feel' for tightness. MAKE CERTAIN the VR is GROUNDED. Dismount it, scrape around the bolt holes, and re-mount using star lock washers.
If it charged when bypassing the VR, and won't with the VR reconnected AND GROUNDED, replace the VR.
That big red wire / connector you posted is likely the battery / ammeter/ charging circuit. I would cut that connector out of there and make a GOOD connection, crimp, etc
Mattax
Just the facts, ma'am
Probably easier to get a good connection in the short term by cleaning it up.
It's difficult to join the fusible link directly to another wire.
Then do it right when as soon as you can. Probably the easiest will be to buy an new fusible link, a replacement connector and terminal.
But it may need new wire. When you're ready to tackle it, slice the insulation open to see how far up the oxidation goes. When moisture can wick in sometimes the copper will oxidize under insulation.
All that said, that connection is not reason for the high charging. But high charging will further damage it.
It's difficult to join the fusible link directly to another wire.
Then do it right when as soon as you can. Probably the easiest will be to buy an new fusible link, a replacement connector and terminal.
But it may need new wire. When you're ready to tackle it, slice the insulation open to see how far up the oxidation goes. When moisture can wick in sometimes the copper will oxidize under insulation.
All that said, that connection is not reason for the high charging. But high charging will further damage it.
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