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Volt meter was down to the low orange line?

7K views 97 replies 14 participants last post by  78 Elk 
#1 ·
I started up the 78 Elk again today. The volt meter went to +13 volts, then dropped to the orange line. Is there a part I need to change in the alternator or do I need to change the alternator?
 
#64 ·
I've taken them off and put them back on during this situation. Makes no difference. I am going to replace the activity wires and see what happens from there. I believe that will make a difference. I just think it's strange that the battery test while running made it do, what it did.
 
#65 ·
After testing the new alternator, which tested great, I put it back on today. I started it up again. It ran great. The voltage meter dropped down again, but after It ran a minute, the needle got up to 13 volts. I'm planning on receiving the new wire end tomorrow evening, so will probably get it put on on Friday. It ran great and didn't use a battery charger of any kind.
 
#68 ·
No, the activity wires is where the problem seems to be. If changing the pigtail doesn't fix it, then I'll check that out. I'm not sure how to do that,since the gauge is touching the printed circuit board, which is working excellent with the other gauges.
 
#69 ·
I started up the 78 Elk again today and the voltage meter read 13 volts, then dropped down to the orange line and didn't come back. I just did this to see if it had improved. I got the new pigtail and hope to get it installed on Friday.
 
#76 ·
I started it up again today and the volt meter stayed in the orange. I put the hand held meter on the battery, it read 14.3 volts. I then went back to the car and the volt meter in there was then 13 volts. I don't know where to look that's making the volt meter so erratic.
 
#77 ·
well, I would expect 14.3 to be correct. anytime I replace a customers battery at work I run the testing meter before. the 14.3 proves that the alternator is delivering power at idle, and the ~14.5 proves it's delivering voltage between 2-3k rpm. sounds like there might be a limiting filter somewhere in the harness
 
#83 ·
I started it up this morning. The needle was in the orange and after 2 minutes it went past 13. I let it run awhile, then shut it off. I let it sit a little bit before I restarted it. When it restarted, it didn't go to the orange, but didn't make it back to the number 13 for quite a while.
 
#84 ·
78, after it is running, can you disconnect the battery and it keeps running? If so, what is on the dash volt meter then, and what is the battery with your hand held meter? As far as the difference between your hand held and the dash, I think the 40 year old meter is low. Mine never gets above 13.5 but my hand held is at 14.5. As long as there is the difference between starting and running I think you are good. The slow come up is the concern.
Tom
 
#85 ·
Thank you Tom. I understand about the difference between the hand held and the car volt meter. The voltage meter read a little higher with the old alternator. I'll try running it tomorrow and disconnect the battery. What does this show me about the volt meter in the car?
Rich
 
#86 ·
Rich, I am trying to eliminate some connections and to see how much voltage on the dash the alternator is putting out without the battery. If you disconnect the plus battery cable it should keep running. That battery cable is still hot while running so keep it away from ground. After reading the voltage hook it back up while running and see how much difference there is. Also before you start it take notice the voltage on the dash with the key on.
Tom
 
#89 ·
I just learned something new, the new pigtail came out on one side. I know I pushed it down when I put it on there. After I ran it a bit ago,I checked it again. It was loose and I pushed it down again. I restarted it and it was over 13 volts, like it should be. I guess I'll have to keep checking it, I don't know the reason it won't stay down on the terminal.
 
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