Charging Problem

Good Evening all:

Now, this is hard for me to do, as a retired electronics/computer/telecom tech, but, you will notice, no automotive in those titles. I replaced my alternator a few weeks back and things seemed fine, but, there was a long period of no driving because, well, it is winter here in Southern Alberta.

I used the car the other day and noticed that, when idling, my voltage gauge goes down to 12.6 volts approx. When I rev up the engine, the voltage goes up to around 14.5 - 15 Volts. I am suspecting that the voltage regulator is my main culprit, but I am not certain.
1: Still runs if I pull off the positive or negative post. Tells me it is still getting an output from the alternator
2: Cleaned the connections to the alternator and the battery. No change.

My son wants to use the car Tuesday to go to work, so has offered to loan me the money to purchase a new regulator, but I don't want to just throw parts at it.

I am just asking for opinions, not miracles, so, does my diagnosis hold water, or should I look elsewhere. I really want him to be able to use the car.

Thank you in advance for any input. I sincerely appreciate it. For now, good night to all, have a pleasant night.

Chuck

 

Your car sounds pretty typical of most older cars. They generally ran lower output alternators than modern cars.

My guess is that your car has a 37 amp output alternator.

You can replace the regulator with a modern solid state unit and it will help a bit, and you can replace the alternator with a 60 or 100 amp unit.

 

Replace alternator with one of the newer internal regulator type.If you like old school look just leave old regulator hanging on the fire wall.

 

I switched to a one wire internally regulated 100 amp alternator about 7 years ago and never looked back. Easy and the electrical system stereo with an amp thanked me. Make sure you get the plug that goes in the external regulator harness (cheap btw)

 

Was it doing it before the alternator change too? Any chance the new alternator has a larger pulley slowing the new alternator down? It would be most noticeable at idle.

 

Could be regulator should be at 13.6 with headlights or the heater on in park. Unless there is a loose wire where it is all connected.

 

Check that big ground wire from engine to body that one is very important for the voltage to work properly it has to be there too.

 

Whoever started the FALSE idea that pulling battery cables off of a battery while the vehicle is running should be shot . This is NO test only a chance to spike the alternator and ruin it . In all my years I have NEVER seen that test described in any manual . If anyone can show a manual describing that procedure I would love to see it . Its an OLD Wives tale .

 

As above, i converted to 10SI alternator (internal regulated) from a 76 buick Electra alternator I had around. It was clocked the same as mine and was a direct bolt in with the conversion kit I will link. No cutting needed.

https://www.summitracing.com/parts/aww-27555?seid=srese1

https://www.napaonline.com/en/p/RAY2134011A

 

Chuck . Being in Alberta I would think that when you had 12.6 at idle the heater was on and the lights and in gear ?? Then when reved up voltage goes up ?? Sounds like the regulator is trying to keep up .

Johns idea to convert is a GREAT IDEA . .

 

At what RPM does the alternator get up to 14 volts+? Just sounds like a typical old car system with a low output alternator to me. There are several reasons I stay with the external regulator..................It's a lot easier and cheaper to replace a regulator if it goes bad than to have to replace/rebuild the alternator.

 

Some of those Regulators don't have a screw . They have to bend a tang to adjust Jason .

 

2 questions -why did you replace the alt? And how did the charging system behave before you replaced the alt, when it was working correctly?

 

Thank you all. The problem seemed to be two fold, at least as near as I could figure out. The plug on the back of the alternator had a little corrosion. Cleaning this stopped the wild fluctuations, but not completely. I replaced the regulator, used electrical contact cleaner on all of the connections, and for good measure, ensured that the belt was tight and not slipping. There was no squealing, but it never hurts to check. When I started the old girl, the volt gauge jumped to 13.4 (~) volts. When I revved the engine up to 15oo RPM, the charging went up to 15 (~) volts. When I let off the throttle, it went back down to 13.4 again. One thing I did find was that the plastic tab on the back of the alternator was depressed. I took it out for coffee and, wait, no stop Chuck. Silliness later, with the Grandchildren. I pulled it out, used a lighter to get it a little warm, not hot, bent it up some and held it until it cooled. Now it is straight, not depressed. I hope that holds it in better. It definitely clicks when I plug it in now, where it didn't before.

On a whim, I am going to clean up the old regulator to see if I can bring it back to life. It is quite a bit heavier than the new one and the new one doesn't use coils, it has transistors. I know, less to go wrong, but, not really period correct. The inside is corroded and dull inside. All of the coils are caked. Cleaning couldn't hurt and, if I can bring it back to life, a spare. If not, the new one was only $18 Canadian.

Once again, thank you all. This problem, while not quite familiar territory to me as a Electronics tech, did help me to boost my troubleshooting skill confidence. I love these old cars, they can be worked on by anyone with the gumption, and some basic tools. Not like my '12 F150 Ecoboost. Wouldn't try to troubleshoot that one, not yet.

Sorry, I almost forgot, I replaced the alternator because it spiked over to full needle sweep a number of times in a row, then settled down to 12 volts. When I checked it with my Fluke, there was no voltage coming out of it and it was hot to touch. The second one I got just didn't work at all, but the third one, a Wilson, seems to work just fine. I have a feeling that the dead alternator took out my regulator, a theory anyways. Maybe I can revive it.

 

I prefer solid state regulators over the original electromechanical units.

To maintain original appearance I replace the small plastic cover of solid state regulators with the cover from an original regulator.

I also prefer to stick with the original type alternator in conjunction with the electronic regulator for the same reason; that setup maintains original appearance while functioning identically to the internally regulated alternators.

 

This is the way to do it. I had issues with my lights getting weak at idle and the solid state regulator cured it.

Swapping covers is also pretty easy.

 

I might have to drill out the rivets they have holding the cover and replace it with the original one. Something to think about anyways. I am so glad to have it running again, and, cheaply too!