Voltage Drop

[Zed Head]

1 hour ago, DoubleYOOHZ said:

I got 16.47v. Seems like the alternator is doing its job at making as much voltage as possible. We can assume the culprit is the voltmeter? 

Do you mean regulator, not meter?  When you connected F to A you had the voltage regulator (VR) out of the system ( I assume that you unplugged the F-N plug to do the test).  

I would remove the regulator and post a picture of it.  See if you can tell if it's the original points VR, or a newer solid-state unit.  Not really sure how the originals typically fail.  Solid-state components can do odd things when they go bad though.

 

[Dave WM]

Yea sounds like the VR possible. they are cheap 30$ on Ebay. If you want I have a video on them

Make note of the statements near the end about making sure the plug is clean, I had some green corrosion on the VR plug.

Edited July 14, 2016 by Dave WM

[DoubleYOOHZ]

I also think it is my voltage regulator. I will take a look at the video and FSM in diagnosing the voltage meter. I will report back. Thanks  @Dave WM

[DoubleYOOHZ]

Before I dive any deeper, I took apart the fusible links and notice something interesting. The fusible link that is registered to the Alternator and Relay seemed to be burnt or charred. 
Kind of weird, dont you think? Maybe there is a reason why my previous fusible link caught fire. I dont think this prohibits my alternator from charging as you can see from the data but I wont rule it out. Any reason as to why this charring happened to the Alternator fusible link? 

[Dave WM]

There seems to be a lot of confusing things going on here. There is a reason the fuse link burned. Most likely a shorted alternator, Or a intermittent short in the wire harness. I am lost as to what is going on now. I think you should start making videos of what you are doing when getting test results like 16v with the VR bypass (F to Batt). Same with getting reduced output at higher RPM and the built in voltmeter including the action of the charge light when the ign is switch to ON and then after the engine is started. I am getting lost in the narrative.

[siteunseen]

I've never seen a fusible link like you've posted above.  You could have some homemade fusible links?  People think they are just wires when they're not.  Here's a good write up from Mr. Blue, it's good info if you haven't already seen it.  http://atlanticz.ca/zclub/techtips/fusiblelinks/index.html

[sweatybetty]

here is a good read on voltage drop

http://www.fluke.com/fluke/uses/comunidad/fluke-news-plus/articlecategories/electrical/diagnosevoltdrop

[DoubleYOOHZ]

 

@Dave WM - Im sorry for the confusion and frustration about this. I am clearly frustrated with the unparalleled data. 

@siteunseen - These are homemade fusible links. I purchased the parts from Oriellys. I did just order a set of factory OEM fusible links. 
@sweatybetty - Thanks for the read! 
 

So... Different results again. I have to test these results in a couple hours if it still produces the same data. 
Basically, from the burnt fusible links that I posted above, I replaced them. I then cleaned battery terminals along with the terminals of all fusible links. Only two are homemade fusible links. 
At idle (around 1100 rpm), the car is hovering above 14v. You can see a jump in voltage when I gas the car.
When the car dips to 12.4v, that is when I turned on the lights of the car. Gassing the engine raised the voltage readings on the battery. What do you guys think? Could it have been just the burnt fusible link that limited my voltage? I am really cautious to not take this reading firmly because I had a different reading before. I will report back with another trial reading.  

[Dave WM]

looks good, but you did not have a battery voltage with engine off, that would have been good to know.

Homemade fuse links are ok IF the wire used is designed for making fuse links. You need the proper gauge, and the insulation should be fire resistant. Any old wire of the correct gauge is not good enough if the insulation will combust and start a fire.

Does the charge light operate properly?

Edited July 15, 2016 by Dave WM

[Zed Head]

When you measured the 16.47 volts, was that at the A terminal, not the battery terminal?  1975 feeds two links directly, one from the alternator and the other after the Ammeter.  The Black Alt/Ign. Relay link is the main charging wire, although I'd think it might backfeed through the green Ignition link, which might explain why you're still getting some charging.

Maybe the meter is the problem after all.  The Black link is fed through the Ammeter.  If the Ammeter was shorted it would blow the link as battery current passed through it.  Whatever is going on, you must have a short somewhere.

http://atlanticz.ca/zclub/techtips/electrical.htm

http://atlanticz.ca/zclub/techtips/fusiblelinks/index.html

[Zed Head]

I was writing the above while posts were being posted.  Not sure where it fits in to the latest data.  Still, fusible links should never burn (that's why the Maxifuse upgrade seems like a fruitless endeavor, to me).  I've never burnt one.

So, your real concern should be about what caused the link to blow.  Examine all of the wires involved for insulation breaks and contact to ground.

[Dave WM]

He may have smoked a non OE fuse link. The only time I had one fail is when the alt shorted to ground, the wire melted inside the insulation which looked perfect on the outside. I would suggest just buying the OE's they are not hard to find and not expensive (under 10$ for a full set IIRC), try that and see if the issue comes up again. If you smoke the correct fuse link the def have a problem. Smoking a homemade could be simply a incorrect homemade.

I have wondered about doing a voltage drop across the fuse link and calculating the amperage across the circuit (I don't have anything that I can directly read the high current, so use the fuse link as a shunt). then compare that to the rate current of the fuse link, the problem would still be I don't know the intended current of the circuit. Was it 50% of the rated current of the fuse link? just don't know.

 

Edited July 15, 2016 by Dave WM