Everything replaced... Alt. still not charging.

1970EK2Duster

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1970 Plymouth Duster 340

Original issue: after sitting for a couple months, engine would crank but not start... when I leave the ignition forward and jump start at the starter relay engine would start and run. My first thought is the ignition switch went bad.

Replaced the ignition switch.

Now the car cranks but no spark... replaced the Ballast resistor.

we now start and run.

BUT now after running for an hour, the battery is dead.

Pulled negative battery cable, engine dies.

Alternator is not getting any power.

replaced alternator and voltage regulator and still not getting any power to the alternator.

last thing I replaced was the starter relay as the positive wire runs through this unit and now have power running to the alternator BUT still not charging and dies when negative terminal is disconnected.

I have a 71 dart that was a known good source (charging system worked) that I have been pulling/ swapping parts with for testing and nothing.


sry for the story but what am I missing?

is it possible the gauge inside the dash got disconnected while working on the ignition switch? possible error with ignition switch? this fusible link I have been reading about?

no damaged wires and the bulk head connectors going into the fire wall are in good condition.

this all worked the last time I drove it...

any help would be greatly appreciated.

thanks!
 

RustyRatRod

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You need to do some diagnosis. Throwing parts at one rarely has the desired outcome.
 

1970EK2Duster

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what would you recommend my next move be?

Battery last time I checked was between 8-9V while running (its dead, I am jump starting every time)

large wire on alternator (secured by a nut) is getting juice (didn't test how much) just poked with a test light.

same deal with the closest smaller wire, has juice. I believe the far right wire is a ground going to the VR.

thanks,
 

RustyRatRod

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what would you recommend my next move be?

Battery last time I checked was between 8-9V while running (its dead, I am jump starting every time)

large wire on alternator (secured by a nut) is getting juice (didn't test how much) just poked with a test light.

same deal with the closest smaller wire, has juice. I believe the far right wire is a ground going to the VR.

thanks,

How much voltage do you see when you put a meter between the big red alt positive and the negative battery post with it running, as post #6 refers too?
 

1970EK2Duster

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crazy... now it is charging.

tested alternator stud to negative battery post: 13.6- 14.01V

pulled battery cable and the cars is staying on. weird because last night working on it nothing was charging.

Gauge in the car still resting on below half and not moving up when changing the RPM...

im going to go buy a lottery ticket lol
 

1970EK2Duster

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crazy... now it is charging.

tested alternator stud to negative battery post: 13.6- 14.01V

pulled battery cable and the cars is staying on. weird because last night working on it nothing was charging.

Gauge in the car still resting on below half and not moving up when changing the RPM...

im going to go buy a lottery ticket lol


assuming the gauge is not reporting positive charging due to dead battery??
 

Dana67Dart

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You need to get a wiring diagram and trace out the wires.

Then you will have a better understanding of what you need to do.

FYI.

There are 4 typs of alternators for our cars.

Single field wire "round back"

Double field wire "round back"

" Single field wire" "square back"

Double field wire "square back"

There are 2 types of VR
single field wire (mechanical and electronic) squareish cover one wire to top one wire to bottom

Double field wire (electronic) v shaped connector
There have been many posts about the wiring of each.

You have to match the alternator to the VR.
Single field wire alternator


2 field wire alternator (round back shown but square back is the same)


Electrical Fundamentals
 
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