Charging system suddenly quit.

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msaund69

msaund69

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Got a strange one. Been driving my 67 Dart /6 "survivor" daily for 2 years. Non electronic charging system, all original. Yesterday she started discharging unless I'm driving 50mph or so. Swapped alternator and regulator with known good units. No change. Cleaned cables etc no issues. Belt fine. Cranks easily.

I know its really discharging based on headlights and secondary amp meter.

Ideas?
 
You say "all original" but then mention electronic

Is this still the 69 / earlier style with one field connection? That is the first question we need to know.

"Quitting completely" is almost always the easiest scenario to troubleshoot as opposed to high or low voltage, or intermittent.
 
Measure the drop from field+ to the 2nd brush. If >4 V, the field should be flowing and the alternator outputting. If 0 V, measure from 2nd brush to case. A bad ground there is likely. Another possible bad ground is from the case to engine block (and to BATT-). That was my problem long ago in Atlanta, and you live in Canada. A new alternator still gave no output, so I connected a jumper cable from case to block and my dash ammeter came alive. Got a refund right in the auto parts parking lot. Of course, the Vreg case also need a good ground (rusty sheet-metal screw?). Field current doesn't flow there, but it requires a "ground reference".

To test the alternator, you can excite the field manually. Unplug the Vreg terminal and connect BATT+ directly w/ a jumper (Radio Shack). Of course, also jumper the 2nd brush to BATT- (don't assume it gets grounded).

Aluminum is very corrosion prone for electrical connections. Just read about all the homes built in the 1960's w/ aluminum wire (next great thing) that burned down.
 
Also engine to chassis ground and negative cable to chassis ground is very important...
 
To simplify a bit what Bill said, unhook the green field wire at the alternator. Use a clip lead and jumper the brush you just disconnected to the starter relay battery stud See if it charges.

If not, measure voltage at the large alternator output stud If it's very very high, perhaps more than 16-18V, you have a break in the alternator charging lead going through the bulkhead to the ammeter

If it's very low, 11V or so, the alternator is not working. Is it possible? Your replacement is either bad, or is a "dual field?" (That term dual field is incorrect, by the way, the 70 / later ones were properly termed "isolated field. They have two brush holders both insulated. Yours has one brush grounded)

I cannot see for sure what you have in that photo. The earlier (70--73 or so) isolated field units were also the "round back" case style
 
Since these beasts charge through the gauge instead of parallel, the bulkhead connector and gauge are also prime suspects. I have eliminated the bulkhead spade connections in the charging circuit on most of my old Mopars for the problems they cause by removing the terminals from the junction block and drilling out the holes for a 10ga wire to pass through and splice into the circuit. Leave enough wire to be able to pull the junction apart if needed.
 
Cleaned \ checked bulkhead connections all seems good there.

So... Jumper from +12 to alternator field causes it to charge. So alternator works. Also works with 12 applied to regulator field connection.

Hooked up normally only 2.4v at alt field (same at regulator field connection) and 11.8v at regulator ignition connection.
 
OK, next

Remove the regulator and jumper those two wires together. Just like hooking the field to 12V this should cause full output, but this time you are checking the wiring "end to end"

Also under the following conditions:

With wires jumpered together

and key in "run" but engine off

Check voltage at battery

and then check voltage at your jumpered connector and post them

Start it up, see if it charges as before

By the way the VR MUST be grounded. MUST

A new VR does not mean a "functional" VR

The only thing I can think of if the above test shows OK is.......

you got a defective replacement VR

or the alternator has / had a partial short in the field. You can measure alternator field current draw. Just hook the field to a battery with your multimeter in series, on DC amps

The fields vary over the years, but somewhere between 3 amps and "just under" 6 amps

Turn the pulley with your hand as you measure as the brushes are sort of intermittent
 
Success! Thanks so much for all the help!

Decided to recheck the bulkhead connections yet again. Crimps still clean and tight and then.....

Wire J2 on the center bulkhead connection labeled N on the schematic breaks off at the crimp on the engine harness. OMG. Replaced the crimp and vroom, charges!

Thanks again you guys are great.

Now anybody know about a Geoflex geothermal furnace?
 
Can you post a link? Download the diagram / destructions?

What sort of animal is it? I used to work on HVAC res. and light commercial, gas, elect, oil, and heat pumps

Sounds like a ground sourced heat pump? What is it doing or not doing?

Frankly, if you know little about electrical and refrigeration, probly time to call "me," LOL "Me" being the me that is younger and in your neighborhood, the honest "me" who fixes this stuff.
 
Thanks for the offer with the furnace. I'm an electrician and an electronics technician so I'm comfortable with working on it. But i learned a long time ago its best to ask for help first than learn the hard way.

Its a GeoFlex geothermal water source heat pump. Last year it had a freon leak. Got that fixed and it worked fine till the season ended. Thing is the compressor has always been "hard starting". Dims lights and can be heard. 2 contractors have said it normal and no issue. Started it 2 days ago and all was fine. This morning I found out it had tripped its 40amp breaker. That had happened last year before the freon leak. Reset the breaker and it ran fine all day. But winter is coming and I don't trust it.

Can't seem to upload manual but below is a link to it in Dropbox.

https://www.dropbox.com/s/zf2xop3bor7863n/GeoflexManual-07-11-11-1.pdf?dl=0
 
msaund69 said:
............... I'm an electrician and an electronics technician ............... Thing is the compressor has always been "hard starting". Dims lights and can be heard. 2 contractors have said it normal and no issue. Started it 2 days ago and all was fine. This morning I found out it had tripped its 40amp breaker. That had happened last year before the freon leak. Reset the breaker and it ran fine all day. But winter is coming and I don't trust it. Can't seem to upload manual but below is a link to it in Dropbox. https://www.dropbox.com/s/zf2xop3bor7863n/GeoflexManual-07-11-11-1.pdf?dl=0
Click to expand...



I would certainly look into the hard start deal.

Does it have what we used to call "start components" or is it just a run cap?

Very first thing I'd do is replace the start cap and start relay, or install them if not present

THEN I'd take a careful look at wiring. You should already know this. Investigate wire size and length of run.

As heat pumps go, ground source should be a lot easier on compressors, because they don't suffer the problems with defrost cycle

This is assuming it was designed / installed and charged correctly, and that the aiflow is up to snuff as well as air side maintenance, coil, blower, filter, etc.

I just wish to heck I could AFFORD one LOL
 
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