1970 240z alternator upgrade

[Phengvang18]

Seeking some advice, I decided to upgrade my stock alternator with a 80amp alternator from zcardepot. 

I  also installed the internal regulator adapter as well and have that plugged in. I currently have the large white/red wire coming from the starter to the B terminal on the alternator.

I have the white/black stripe wire (L lamp signal) plugged into the ignition key pictured below in the diagram ( which is the pink wire in my picture below)

And I have the yellow wire (sense signal) which is the green wire in my photo plugged into to the 12v post in the picture diagram below.

And I have the black ground wire on the casing of the alternator.

 

With the battery fully charged and car running it was at first posting 14v plus while running but now is not holding any charge. 

Any ideas what went wrong? Or did I plug the wires incorrectly? 

 

I seen diagrams where they installed a halogen light bulb in line into the white/black wire, do I need to do this? 

do I need to rewire the thick white/red wire straight to the battery instead of having it connected to the starter and add a fuse box in between? 

Thanks

Edited April 7, 2021 by Phengvang18

[S30Driver]

9 hours ago, Phengvang18 said:

 

With the battery fully charged and car running it was at first posting 14v plus while running but now is not holding any charge. 

Any ideas what went wrong? Or did I plug the wires incorrectly? 

I seen diagrams where they installed a halogen light bulb in line into the white/black wire, do I need to do this? 

do I need to rewire the thick white/red wire straight to the battery instead of having it connected to the starter and add a fuse box in between? 

Thanks

 

 

I assume that the external regulator is now un-plugged and not in the circuit.

With the car running at idle or say up to about 1000 rpm,  measure the voltage output at the alternator (your red wire) and tell us what it is.

The wiring looks to be correct.     No to the light bulb,  and no to connecting the alternator direct to the battery.  It looks like you have replaced the alternator output wire to the starter with a thicker gauge which is good considering you have doubled the current this wire can potentially carry.

[Zed Head]

13 hours ago, Phengvang18 said:

With the battery fully charged and car running it was at first posting 14v plus while running but now is not holding any charge.

Not really clear what the problem is.  You mentioned voltage from the alternator, but said that something "is not holding any charge".  Is the battery dying?  Does it die right away or overnight, or over a few days?

[Phengvang18]

1 hour ago, Zed Head said:

Not really clear what the problem is.  You mentioned voltage from the alternator, but said that something "is not holding any charge".  Is the battery dying?  Does it die right away or overnight, or over a few days?

 

When I first installed the new 80amp alternator, it appears that it was charging the battery while running, posting 14v plus while running, but now it is not charging the battery anymore only posting 11v if at full charge and will gradually settle or die if the car continues to run. 
 

The battery dies within a few days. This is a agm battery and only 1 year old. 
could my alternator be faulty? 

 

[Zed Head]

It might be that one of your wires came loose.  Check for voltage on the purple and cyan wires with the key on.  One is the Sense wire (for the internal regulator) and the other energizes the windings to allow the alternator to charge.  Might be that you lost one of those. 

I have read that some of the adapters can fail.  That would be the most likely place to look if you don't have voltage at the purple and cyan wires.

[Phengvang18]

10 hours ago, S30Driver said:

I assume that the external regulator is now un-plugged and not in the circuit.

With the car running at idle or say up to about 1000 rpm,  measure the voltage output at the alternator (your red wire) and tell us what it is.

The wiring looks to be correct.     No to the light bulb,  and no to connecting the alternator direct to the battery.  It looks like you have replaced the alternator output wire to the starter with a thicker gauge which is good considering you have doubled the current this wire can potentially carry.

Yup, the external regulator is unplugged.    With a fully recharged battery reading at 12v, I measured the voltage output while the car is running at the alternator (red wire) and got a reading of 12v.  I also measured the voltage while the car was running at my green wire (sense wire) and it also reads 12v.   

Would the culprit be that my new alternator is out? 

[Phengvang18]

2 hours ago, Zed Head said:

It might be that one of your wires came loose.  Check for voltage on the purple and cyan wires with the key on.  One is the Sense wire (for the internal regulator) and the other energizes the windings to allow the alternator to charge.  Might be that you lost one of those. 

I have read that some of the adapters can fail.  That would be the most likely place to look if you don't have voltage at the purple and cyan wires.

With a fully recharged battery sitting at 12v,  I checked voltage on the cyan colored (Sense wire) and it reads 12v  and the purple colored ( L lamp signal wire) reading 11.50v with the key turned to "ON".  

I've also changed the internal regulator adapter, which I have two of as well. 

 

Could it be that my new alternator is bad thus it isn't charging?

 

Thanks

[S30Driver]

Yes, unfortunately it appears the the new alternator has failed.   Time to invoke the warranty for exchange ...

[Zed Head]

Agree with S30.

It seems that way.  Your wiring has the correct voltages.  Have the alternator tested at a parts store.

It looks like you have the ground wire connected also but you might as well confirm a good ground with your meter.  Measure continuity from the alternator case and the ground post to the body and/or engine block and the negative post of the battery.

It's  a bummer when new parts fail right away.  Good luck.

[Phengvang18]

Thank you guys! I appreciate the quick responses!  

[Phengvang18]

23 hours ago, Zed Head said:

Agree with S30.

It seems that way.  Your wiring has the correct voltages.  Have the alternator tested at a parts store.

It looks like you have the ground wire connected also but you might as well confirm a good ground with your meter.  Measure continuity from the alternator case and the ground post to the body and/or engine block and the negative post of the battery.

It's  a bummer when new parts fail right away.  Good luck.

Quick question as I've been reading a few threads.  How is overcharging caused? What is the best way to determine or find what's causing the overcharge?  

I believe the reason why my previous new alternator died may be because of overcharging,  because when I first installed the new alternator, my amp meter in the car was not in between -60 , +60,  it was leaning heavily to the +60 side. 

[Patcon]

If your battery is very low or weak it can demand a lot from the alternator. Killing it...