TheBMan Posted April 25, 2023 Share Posted April 25, 2023 Hey guys. The 70 MC that I purchased had an internal regulator alternator on it. I put it back to stock with a new external regulator alternator (three wire) and new external voltage regulator. I am seeing 16+ volts at idle. I looked at the wiring diagram for the car and made sure that the blue and white wires run to the regulator and have continuity. The F wire (blue) is hot with the key on. I read that the other wire should be hot all the time. Is that with key on or off or both? My white wire is never hot. I have Googled and Googled and Googled and what I can't confirm is which terminal is which on the alternator. Mine is not labeled F and R (or 1 and 2) as some are. You can see in one of the photos how I currently have it connected. Also, trying to figure out what the disconnected wire is as seen in one of the attached photos. Is this related to the charging system? It was this way when I purchased the car. Any help is appreciated! Quote Link to comment Share on other sites More sharing options...
jft69z Posted April 25, 2023 Share Posted April 25, 2023 17 minutes ago, TheBMan said: Mine is not labeled F and R (or 1 and 2) as some are. Looking at the alternator, R will be on the left, F will be on the right. 1 1 Quote Link to comment Share on other sites More sharing options...
TheBMan Posted April 25, 2023 Author Share Posted April 25, 2023 4 minutes ago, jft69z said: Looking at the alternator, R will be on the left, F will be on the right. Thanks Joe. That means I have those wires correct. That's one thing I can eliminate as the possible problem. 1 Quote Link to comment Share on other sites More sharing options...
jft69z Posted April 25, 2023 Share Posted April 25, 2023 A factory service manual has all sorts of very detailed troubleshooting information for that charging system. May be a good investment to pick one up (PM me). 1 Quote Link to comment Share on other sites More sharing options...
TheBMan Posted April 25, 2023 Author Share Posted April 25, 2023 1 hour ago, jft69z said: A factory service manual has all sorts of very detailed troubleshooting information for that charging system. May be a good investment to pick one up (PM me). You're absolutely right, I do have a manual and I just got done reading the test procedures. I put a test light on terminal F and 4 at the regulator; the test light lit up. The manual says that means a bad regulator. I have [another] new one coming. I'll install and re-test. 2 Quote Link to comment Share on other sites More sharing options...
TheBMan Posted April 25, 2023 Author Share Posted April 25, 2023 @jft69z Problem solved. I replaced the new voltage regulator with another new unit and the voltage is now 14.3. Perfect. I was questioning myself in this entire process because I had the re-convert the car back to external regulator and had to fix some wiring, which isn't my strong suit. That said, your tip to check the manual (duh) was the closer. Appreciate the tip and the help. Sometimes we just need a little nudge. 😉 3 Quote Link to comment Share on other sites More sharing options...
jft69z Posted April 25, 2023 Share Posted April 25, 2023 4 minutes ago, TheBMan said: @jft69z Problem solved. I replaced the new voltage regulator with another new unit and the voltage is now 14.3. Perfect. I was questioning myself in this entire process because I had the re-convert the car back to external regulator and had to fix some wiring, which isn't my strong suit. That said, your tip to check the manual (duh) was the closer. Appreciate the tip and the help. Sometimes we just need a little nudge. 😉 Glad it worked out for you! A lot of the times it's the simple stuff, but without actually troubleshooting and verifying something is bad, you'd just be throwing new parts at the problem until something finally works. Other times, it's just a nightmare that'll keep kicking your azz 😄. 6 Quote Link to comment Share on other sites More sharing options...
Jeffrey Aldrich Posted July 28, 2023 Share Posted July 28, 2023 Did you find out the fix for this? Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 28, 2023 Share Posted July 28, 2023 14 minutes ago, Jeffrey Aldrich said: Did you find out the fix for this? Look 2 posts up....he replaced the regulator. 1 Quote Link to comment Share on other sites More sharing options...
Jeffrey Aldrich Posted July 28, 2023 Share Posted July 28, 2023 OOPs didn't see that...yeah, I tried that four times. I still have a overcharge issue I think. And my head lights brighten and dull depending on RPM. Seems to be eating up regulators? Could it be the external capacitor? I have heard the capacitor is for RMI and heard is just for pulses generated by a mechanically operated NOS regulator. Just looking for some more information. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 28, 2023 Share Posted July 28, 2023 34 minutes ago, Jeffrey Aldrich said: OOPs didn't see that...yeah, I tried that four times. I still have a overcharge issue I think. And my head lights brighten and dull depending on RPM. Seems to be eating up regulators? Could it be the external capacitor? I have heard the capacitor is for RMI and heard is just for pulses generated by a mechanically operated NOS regulator. Just looking for some more information. Have you tried a newer style, electronic regulator? What type of system voltages are you looking at during idle & at 2000RPM? Unless you're really concerned about remaining original, a conversion to an internally regulated alternator may be a consideration too. That would probably kill 2 birds with one stone, lol. At any rate, more troubleshooting would be required, preferably tests like the running voltage as mentioned earlier, AC ripple ( looks at alternator diodes), etc. I'd be steering towards getting your alternator checked, even though you said it was rebuilt in the other thread . Maybe your local parts place can test it. Have you disconnected that external filter from the regulator and run it? Quote Link to comment Share on other sites More sharing options...
Jeffrey Aldrich Posted July 28, 2023 Share Posted July 28, 2023 Actually ordered the filter I guess you mean capacitor. That's why my post is named capacitor I am trying to see if my issue is just that simple. As far as voltages when the alternator turns on by the blue wire i could see 17 volts easy. I just saw this post and wondered if he had tried that. Some people say its RMS capacitor some say its spiked voltage changes that it helps with. Simply stops burning points in regulator. etc. Quote Link to comment Share on other sites More sharing options...
John S Posted July 28, 2023 Share Posted July 28, 2023 According to the 1970 chassis service manual on the engine, electrical Chapter it states you can adjust the regulator voltage. I don’t know if replacement regulators have this option or not but I’m looking at it in the book. Quote Link to comment Share on other sites More sharing options...
Jeffrey Aldrich Posted July 31, 2023 Share Posted July 31, 2023 Thank you that's important. what manual do you have? Quote Link to comment Share on other sites More sharing options...
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