Charging failure?

[WhiteOnGreen]

Hello,
Recently in the last cruise the ammeter needle began to oscillate from the 0 to +20 mark violently and rhythmically when I kept the engine over approximately 2500 rpm.

So I started to diagnose the problem and believed that the most common would be a regulator failure but after checking the voltage with a multimeter, it was somewhat high and I replaced it with another. Same result
I checked the grounds (good at regulator) and also checked the bulkhead connector and the dark blue ignition wire had some resistence, for test only bypass the ignition wire direct to batery and the multimeter reads ok 14,5 14,7 ish

Next clamp the multimeter to alternator pos to verify output and  put the engine at 2500 rpm. Result multimeter reads steady 14,7v but ammeter stay jumping.

Disassemble the dash and confirmed that the connections to the ammeter are firm plus ammeter is direct connection from engine compartment  bypass completly the bulkhead connector
Now I´m a little lost and I suspect the alternator but it seems strange to me since the reading it gives is correct.
Any ideas?

Thanks in advance

[Nacho-RT74]

La lectura hacia el lado de carga indica que algo del lado de la batería está requiriendo carga. Tienes algun accesorio conectado directamente a la batería?

[b5blue]

This may help.  http://www.bcae1.com/

[WhiteOnGreen]

La lectura hacia el lado de carga indica que algo del lado de la batería está requiriendo carga. Tienes algun accesorio conectado directamente a la batería?

Hey Nacho, Thanks
Nope, stock factory installation except wires atach to ammeter.for test pourpose all accesories wiring disconect from fuse box. Same result. Bad ammeter?

[birdsandbees]

Still using a single field alternator or has someone "upgraded" it to a dual field '70 style? If dual, your blue wire from field to regulator is either broken somewhere or has a loose connection that vibration at 2500+ is farting with the connection.

[Nacho-RT74]

Ammeter is not a gauge easy to beat. They could work or not ( and that's just after a huge failure ) but never get a bad reading like that

[Nacho-RT74]

Still using a single field alternator or has someone "upgraded" it to a dual field '70 style? If dual, your blue wire from field to regulator is either broken somewhere or has a loose connection that vibration at 2500+ is farting with the connection.

Or simply a brush failure... however with a missed field ( either wire or brush ) it shouldn't be flicking between zero and +, but between - and +. A missing field connection will automatically get an unnoperative alt, and will get you on discharge rate.

I'm toward to an intermitent missing batt to amm conection... or resistive path on same wire section.

Thinking it good, the ammeter could be showing streess symptoms on studs inside the gauge. That's something to check. However it is weird voltage reading keeps on a steady value still with the flickering

[WhiteOnGreen]

Still using a single field alternator or has someone "upgraded" it to a dual field '70 style? If dual, your blue wire from field to regulator is either broken somewhere or has a loose connection that vibration at 2500+ is farting with the connection.

System upgrade, 70 setup dual field alternator(squareback) and electronic regulator since I installed the electronic ignition 10 year ago

[WhiteOnGreen]

Still using a single field alternator or has someone "upgraded" it to a dual field '70 style? If dual, your blue wire from field to regulator is either broken somewhere or has a loose connection that vibration at 2500+ is farting with the connection.

I'm toward to an intermitent missing batt to amm conection... or resistive path on same wire section.

Thinking it good, the ammeter could be showing streess symptoms on studs inside the gauge. That's something to check. However it is weird voltage reading keeps on a steady value still with the flickering

3 year ago when I did the conversion to led lights in the dash panel, I soldered the studs of the ammeter and installed some new phenolic fiber insulators but I understand that it is also different to measure voltage than amperes

I will check the wiring again and disassemble the alternator to check the brushes

Thanks for all support

[Nacho-RT74]

So you made the complete check out on the charging system! LOL.

Actually brushes can be checked without dissasemble the alt itself. Maybe just remove from engine bay. Sometimes on some models brushes are accesible still with alt on engine. I think 68s are still like that on BBs. As far I recall is on 69 when the alt mounting changed to be adjusted from bottom instead from top like on earliers ?

Yes, sure volts and amps are still being related two diff values. While a volt can reach a value by just one copper strand, an ampere could not and that same strand could blow. Thats how a fuse works.

The deal here is, you are getting load going throught the amm up to the batt side for whatever reason. That's the only reason the needle finds the way to move.

[WhiteOnGreen]

Update.
Bad alternator. I installed other brand new and ammeter spikes go out.
I suspect bad diode since brushes is OK.
Could the ammeter be detecting AC spikes?
Another question is that I need to renew the wiring of the engine compartment and the complete bulkhead connector rebuild, there is still resistance in the ignition cable resulting in the alternator sending 15.1 volts to the battery.
Where is the best place to buy GXL wire with the correct color scheme, there is an installation part that I want to modify and the specific harness wiring that they sell does not work for me

[Nacho-RT74]

A bad diode wouldn't give enough amp output still keeping the voltage. So it should give a small discharge at iddle.

I will share an experience I got. Once I got allmost 18 volts and a heavy decay on amperage. Revving up the engine, was able to get up to 24 volts and ammeter barelly passing the zero reading to positive side. Everything was perfect with the alt out of the car, but once installed this failure floated on. At the end I found one of the rotor vent vanes was getting friction with one of the stator leads going to the diodes bank. After 2 hours checking the alt out of the car began to spin it with hand and could feel a small "stop" every turn. It was barelly noticeable. Just bent a bit that stator lead and everything become normal again. That fricton caused an instant short on every spin and I guess regulator tried to compensate that with voltage.

Sure the fail I got was not similar to your fail, but could be something to check.

About colored wiring in AWG, I have found several sources on eBay selling some meters/feets rolls ina variety of colors and gauges. Dunno what you meant about GXL?

Bulkhead plastic conectors... megapartsusa is one good source. They also sell the terminals, but there are cheaper sources for terminals being sold as a bulk. Originally, Chrysler used Packard 58 for female terminals and Packard 56 for male, HOWEVER packard 56 are fine to be used as male and female terminals on our plugs.

Amm and AC spikes? I think it could, but I can find hard some AC current will go through the diodes bank. A Diode tipically fails into an open circuit, and not a closed full path circuit? Dunno. It can be checked with a multimeter into the ohms scale thought. If some diode reads continuity with tester leads on any side, I guess that's posible

As I mentioned, the ammeter will sense loads GOING THROUGHT the amm. If there is not a device requesting for load on the opposite side, there is no load being sensed, still if alt is able to produce it. So, if that spike was going throught the amm I guess it was being requested by the batt on that specific instant.

Well I'm not an electric engineer, but as a sound tech and some electrical experiences, I know just a bit of basic electricity

[WhiteOnGreen]

Thanks Nacho,
Electricity is not my best skill despite having studied some electronics many many moons ago 
I'm going to check the alternator to try to find out what the fault may be.

[Nacho-RT74]

Forgott to say, packard 58 terminals are nearly imposible to find, hence why tipically the direct replacement is the packard 56 for females.

[Nacho-RT74]

About terminals

https://www.forabodiesonly.com/mopar/threads/packard-56-terminals.472278/

https://www.forabodiesonly.com/mopar/threads/sources-for-chrysler-type-wire-terminals.418908/

I have used any replacement available at local grocery stores in Venezuela thought, very similar to the "Yazaki" on those pics, and fit nicely

[Kern Dog]

La lectura hacia el lado de carga indica que algo del lado de la batería está requiriendo carga. Tienes algun accesorio conectado directamente a la batería?

Why would you respond in Spanish?

[Nacho-RT74]

La lectura hacia el lado de carga indica que algo del lado de la batería está requiriendo carga. Tienes algun accesorio conectado directamente a la batería?

Why would you respond in Spanish?

He is from Spain... just to far away from me to personally help him.

[Kern Dog]

Every other response from you was in English.
My point was that this is a forum where people use English. The OP obviously does. It just seemed odd to write in Spanish and exclude the majority of the members with a foreign language.
You are always a helpful guy and your contributions are appreciated.

[John_Kunkel]

My point was that this is a forum where people use English.

Well, a modified form of English. 

[Nacho-RT74]

Mostly sure it was faster and easier to me to response in Spanish at the moment. There was not any extremely relevant information on my reply that somebody could miss. I continued in english after that because he replied in english.

[Nacho-RT74]

My point was that this is a forum where people use English.

Well, a modified form of English. 

Once chatting with a guy from Sweden on this forum ( via PM ) he told me it was easier to understand my posts than read some members around here LOL

[Kern Dog]

I can see the truth in that.