I think there is a misunderstanding of "Charging"
In American English it is common to say "charging" to say that the alternator is providing power.
We also commonly will say "Battery" to refer to supply power regardless of whether the power is actually coming from the battery or in fact coming from the alternator.
How this
may relate to your observations is as follows.
You have stated the EFI equipment was connected at the battery.
When the engine is running, power is supplied by the alternator at 14 + Volts.
If you are looking at the ammeter, it should only read 'charge' or "+' when the battery is charging.
When the battery has been recharged it should read zero (in the middle)
View attachment 1716450837 or
View attachment 1716450838
However, because the EFI is now connected to the battery, the ammeter will always read 'charge' with the alternator running.
Let me illustrate this with a diagram.
This shows about 10 amperes flowing to the battery because it is recharging.
View attachment 1716450843
When the battery is fully charged, the ammeter shows zero current flowing to the battery.
The alternator is still supplying 14 Volt power to the ignition (and anything else that is switched on).
View attachment 1716450844
With EFI and electric fuel pumps connected to the battery, the ammeter will show current going to those items in addition to current to recharge the battery.
View attachment 1716450849
So the ammeter is no longer showing battery charging.
It is showing battery charging
plus current draw for EFI and anything else that has been connected at the battery.
Damage to the positive diodes on the alternator can be an easy repalcement on some alternators. We've seen photos of alternators used on South American Chryslers that are different than the ones typiclly used on US, UK, and Canadian builds. I don't know what is on your car. The one in the first photo like a Chrysler alternator. The 'round backs' have press in diodes that require a special tool and soldering. The squareback version is bolt in.
I would suggest rewiring the main power supplies in a manner that would supply the EFI and fuel pump without going through the ammeter and fusible link. Some ideas
here and more complex ones using a relay
here
You may wish to add a voltmeter that is switch on when the key is in run or accessory.
Even though your car is similar in some ways to US built A-bodies, you may want to join For B Bodies Only and have a conversation in Espanol with
Nacho-RT74 That will reduce errors in translation.
