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Battery not charging an engine dies

gtx-

gtx-

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Currently i’m troubleshooting a Plymouth GTX from 1968, the car is running and driving smooth for 30 seconds. after that the engines runs so rough that it will shutdown itself after hesitating.

The first thing I have tested was the battery and tried my second battery, booth were fine, then I noticed while running the engine, the battery I not charging at all.

Unplugged all the wires, cleaned small corrosion and checked all the fuses, that should be ok now, but was not the problem.

I have tested all the ground wires, smoothed them up, but they were still ok.

Then the alternator came to my mind, i checked all the belts (new) and they don’t seem to be to tight, started the engine, checked if the pulley from the alternator is spinning, it did. After that step I went in with the multi meter here are the alternator results:

(Engine-Off)Battery 13.3 V

(Engine-Running) Battery 12.5V (not charging)

(Engine-Off)Alternator 11.7 V

(Running) flipping between 0 V and 9,5 V very fast

I could not test the other 2 wires on the alternator because the wires from multi meter were not long enough.

Any thoughts? Maybe the volt-regulator or seems clear that the alternator is death..?
 
Alternator is bad. Probably needs new diodes. Do you have a shop that can test it off the car?
 
Whats the voltage on the input side of the voltage regulator? I've had the reg go bad before.
 
max340 said:
Whats the voltage on the input side of the voltage regulator? I've had the reg go bad before.
Click to expand...
I will test that tonight,voltage with engine running, off or ignition on? :)

Update:
With the ignition on, the input side of the voltage-regulator shows 9.6V
 
Last edited:
Is this an all stock car or are there any mods that have been done that connect to the electrical system ?
 
Did this problem happen all at once ? Or was it an intermittent problem ? Were any items recently changed or worked on before this problem ?
 
MoparLeo said:
Did this problem happen all at once ? Or was it an intermittent problem ? Were any items recently changed or worked on before this problem ?
Click to expand...
Yes, bought the car a Year ago.
After that it had been sitting down for the whole year in an old cold barn.
Drove it once and engine stopped running, checken the battery and thougt that was the issue at that time.
Now i have time to troubleshoott :)
 
Also seems like a problem..

DD9814F0-02B2-4127-A009-E2F20D7FE7D3.jpeg C15C2277-B9E9-45BB-875C-B88F9B82939E.jpeg
 
No doubt. That mess needs to be fixed first. Probably good that the car doesn't run right now. That would be my first priority. Check and service all the wiring in the car. Otherwise you will constantly have problems.
You might consider replacing the harnesses. They cost money but are the heart of your cars systems. And they are obviously in need of repairs. Over 50 years old and not much maintenance has been done. The insulation gets brittle and cracks causing shorts. Other wires have been added improperly...
 
Pics of your bulkhead connector look like a meltdown ready to happen. If it was my car, I would be ordering a new engine and dash harness at the minimun.
 
MoparLeo said:
No doubt. That mess needs to be fixed first. Probably good that the car doesn't run right now. That would be my first priority. Check and service all the wiring in the car. Otherwise you will constantly have problems.
You might consider replacing the harnesses. They cost money but are the heart of your cars systems. And they are obviously in need of repairs. Over 50 years old and not much maintenance has been done. The insulation gets brittle and cracks causing shorts. Other wires have been added improperly...
Click to expand...
The middle connector is the worst, do you know the name of the connector or a kit which i can replace? Or a whole harness for under the hood
 
Go to your welcome post I listed a few parts suppliers and links to them. Year one carries and exact replacement harness of very good quality and have volume discounts.
 
Keep it simple. Previous post mentioned have the alternator tested. Other post mentioned voltage regulator, if you have electronic ignition, that will require an electronic voltage regulator. And most important is get a Mopar shop repair manual for your year car. Rockauto, ebay and Amazon have them. They're being reprinted for $30-60. Invaluable for tracing wires. The print will tell you about all the connections at the bulkhead. Replacing parts not knowing if the item is bad gets expensive. I have heard the aftermarket wire harnesses can be 'Pain full'.
 
1963JAM said:
Keep it simple. Previous post mentioned have the alternator tested. Other post mentioned voltage regulator, if you have electronic ignition, that will require an electronic voltage regulator. And most important is get a Mopar shop repair manual for your year car. Rockauto, ebay and Amazon have them. They're being reprinted for $30-60. Invaluable for tracing wires. The print will tell you about all the connections at the bulkhead. Replacing parts not knowing if the item is bad gets expensive. I have heard the aftermarket wire harnesses can be 'Pain full'.
Click to expand...

I think it is wise to first make sure the wires on the bulkhead are in a good shape, then see if the issue is still the same, in the meantime while ordering new wires check if the alternator is in a good shape.
Yes i have an electronic ignition with voltage regulator.
I think an aftermarket set like:
https://www.classicindustries.com/product/1968/plymouth/gtx/parts/mb2398.html
cannot be worse then the one that is sitting on the car right now :)

I will check eBay for a manual repair guide for 1968!
 
After rereading your original post I had a similar situation with engine shutting down when I first bought my car. Turned out the ECU was the issue. In my case it would die on a hot day after the engine would heat up over 180. It would die at an intersection of course. Check ECU wire to coil for voltage when cranking.
 
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