Replaced engine compartment wiring, now having charging problems

-
Richard Deering

Richard Deering

FABO Gold Member
FABO Gold Member
Joined
Sep 16, 2018
Messages
17
Reaction score
2
Location
Petaluma, CA
I converted to electronic ignition and replaced the forward wiring harness in my 1965 Dart as well as all main components. Now it doesn't seem to be charging. Runs fine for a while then loses power and dies with dead battery. Replaced VR, but still happening. I'm thinking maybe a grounding problem but everything seems to be okay. I'm running out of ideas. Does anyone have any suggestions what to check next?
 
Too many what ifs.

First, what is the voltage at the battery when it is fully charged engine off?

When it is fully charged what is the voltage with the engine running.

What does the charge indicator show?

Was your replacement harness designed for 2 wire square back ALT?
 
Dana67Dart said:
Too many what ifs.

First, what is the voltage at the battery when it is fully charged engine off?
12.5

When it is fully charged what is the voltage with the engine running.
14-ish


What does the charge indicator show?
Slightly toward charge for a while, until things go haywire and it pegs out charge and discharge. Lights dim, blinkers slow down, power seems to fade out and engine dies. I can get a few successful brief starts, then the battery is dead.
Was your replacement harness designed for 2 wire square back ALT?
Click to expand...
Yes.
Dana67Dart said:
Too many what ifs.

First, what is the voltage at the battery when it is fully charged engine off?

When it is fully charged what is the voltage with the engine running.

What does the charge indicator show?

Was your replacement harness designed for 2 wire square back ALT?
Click to expand...

C3E8B914-7558-4FC2-B824-A2837B42C595.jpeg
 
Do you are saying that after a full charge to the battery everything seems correct. Then out if no where, the charge indicator will peg at full charge (full right) then full discharge (full left) then engine dies.

How long does it stay at full charge or discharge?
 
What is the red/ blue? Normally one field is blue, the other green. Check with key "in run" that you have battery voltage to the blue field wire. Disconnect the green in subdued light, and connect/ disconnect it a couple times. You should be able to see a small spark.

If you have voltage at the blue, take a clip wire and jumper the remaining field terminal to ground, with that same field wire disconnected. Run the car, slowly bring up RPM Monitor battery voltage it should rise. If not monitor the alternator output stud and repeat. If it rises quite high, you have a break in the path from alternator output to the battery. IF that terminal stays low, around 12--12.5 it is not charging.

If not make sure field is drawing current. Ground either field terminal, connect remaining to battery, and measure current through it with your meter. Should draw 3 to 5 A or so.
 
These are simple. The VR controls "the ground side" of the field, and pulses more current to the field to get more out of it. So the blue wire is key switched 12V on one end of the field, and the remaining field is the green going back to the VR is the control wire. You can simply connect the field to battery and ground---matters not which field terminal is battery........and it should charge.
 
Dana67Dart said:
Do you are saying that after a full charge to the battery everything seems correct. Then out if no where, the charge indicator will peg at full charge (full right) then full discharge (full left) then engine dies.

How long does it stay at full charge or discharge?
Click to expand...

It was just a couple of seconds each.
 
When you say the battery is dead... Dead as in will not crank or cranks but does not fire.

How long do you have to put it on an external charger to try again?

With your alternator output of 14 + volts the engine should keep running even if the battery was disconnected (bad idea don't do that) since it only takes seconds for the engine to die I would say there is an intermitnant short some where.

You haven't said if you have had the battery tested.

Recently my 67 dart had a low battery, cranked for a bit but wasn't enough to fire. Jump started it and it was charging at the first bar to the right of center.
I was getting 13 to 14 volts at the battery so it was charging

I drove it for 45 minutes and it stayed there the entire time.

Suspecting the 3 year old battery might have a problem. Took it to store, they tested and said it was ok just low on charge. I put the batt on charger all night and the next day the charge indicator was back to center.

It's working fine now.

Reason I bring this up... If battery has a internal short, it might register high charging current and then alt can't keep up and stops trying to charge (overheats) now you have no voltage and the engine dies.
Just a theory.
 
Dana67Dart said:
When you say the battery is dead... Dead as in will not crank or cranks but does not fire.

How long do you have to put it on an external charger to try again?

With your alternator output of 14 + volts the engine should keep running even if the battery was disconnected (bad idea don't do that) since it only takes seconds for the engine to die I would say there is an intermitnant short some where.

You haven't said if you have had the battery tested.

Recently my 67 dart had a low battery, cranked for a bit but wasn't enough to fire. Jump started it and it was charging at the first bar to the right of center.
I was getting 13 to 14 volts at the battery so it was charging

I drove it for 45 minutes and it stayed there the entire time.

Suspecting the 3 year old battery might have a problem. Took it to store, they tested and said it was ok just low on charge. I put the batt on charger all night and the next day the charge indicator was back to center.

It's working fine now.


Reason I bring this up... If battery has a internal short, it might register high charging current and then alt can't keep up and stops trying to charge (overheats) now you have no voltage and the engine dies.
Just a theory.
Click to expand...


The battery was dead. Won't crank at all. I took it to the local Autozone for charging and testing. Took them a few hours to charge. Test showed it was fine. This is the second time this sequence of events has taken place. After the first time, when I had the battery charged, the car ran fine for a while.

Took the car to a mechanic after the first event. He checked it out and did some other work. Ran fine for him. I drove it home with no problem. After about 30 min. of driving time over a couple of days all this stuff started up again. Put fully charged battery back in yesterday. Starts fine but low idle and dimming lights.
 
67Dart273 said:
What is the red/ blue? Normally one field is blue, the other green. Check with key "in run" that you have battery voltage to the blue field wire. Disconnect the green in subdued light, and connect/ disconnect it a couple times. You should be able to see a small spark.

If you have voltage at the blue, take a clip wire and jumper the remaining field terminal to ground, with that same field wire disconnected. Run the car, slowly bring up RPM Monitor battery voltage it should rise. If not monitor the alternator output stud and repeat. If it rises quite high, you have a break in the path from alternator output to the battery. IF that terminal stays low, around 12--12.5 it is not charging.

If not make sure field is drawing current. Ground either field terminal, connect remaining to battery, and measure current through it with your meter. Should draw 3 to 5 A or so.
Click to expand...

Yes, showing 11.6 at blue wire with key "in run" position.
Yes, spark from green terminal.
Connected clip wire from other field terminal to ground. Ran engine. Battery voltage at 13.9 at idle. Rose to over 17 V as bringing up RPM.
 
You must log in or register to reply here.
-

Back
Top