Over Charging Electrical System

[frank in ga]

Hello everyone and let me say how thankful I am to find such a forum. Also, many thanks to Steve Allen for getting my log on to work. Thank you Steve!

Recently I purchased my first Roadster, a 67 1600. I've admired Roadsters and Fair Ladys since I was 14 years old and my neightbor gave me a ride to my freshman high school in his 3 month old 65 Fair Lady in French Blue. The sounds, the responsiveness, and the curves were oh so different than my fathers Buick. Well, I've finally purchased one. I've known the car for almost 20 years as it was owned by frinds of mine in Arizona. In 1990, they had it stripped and painted but never finished putting it back together. I just ordered a complete interior for it and last week put on some Revolution 14x6 Alloy Wheels. I want to have the car finished in time for the event at Road Atlanta in April.

There is one small problem I'm having and wondered if anyone else has already gone through the pain and may have an idea what the problem is.

The electrical systems is overcharging. The ammeter says it's charging at approximately 10 amps at idle and over 30 amps once the revs come up. The water in the battery boiling over is another indication. As I wasn't sure how old some of the componets were, I replaced the battery, then had the alternator rebuilt by a local rebuilder and purchased a new regulator. The insulator over the wires on the bottem of the regulator were also melted. The Rebuilder said I might have had the wrong regulator or something is wrong with the wiring because there was indication of the alternator also getting very hot. He replace all the diodes, the stator, and a couple of other parts. I've used this company before with great results. They've been in business for over 40 years. I bought a new regulator from NAPA. Upon firing the vehicle up, ..........same thing! THe ammeter was reading over 30 amps. I turned the engine off after less than a minute of running and noticed the alternator was extremely warm to the touch. Some of the wires that go from the 6wire plug off the regulator and go to the 4 wire plug on the alternator have been replaced (of course with different colors just to make things fun. They appear to be going to the proper locations in the 4 plug connector but I really am having a hard time trying to read the schematic in the shop manual.

Any words of wisdom? Does anyone have a picture of what wires go from the 6 prong connector to the 4 prong connector. Or has anyone else ever had this problem? Thank you agian, and I'm looking forward to repaying the favor. Frank Filicicchia (pronounced Fil-s-cheek-ee-a).

[datsun65]

Sounds like you have a bad voltage regulator...

Just a side note...A few folks have been swapping over to the GM alternator option, in which an inexpensive GM alt is used. It contains an internal voltage regulator...so it simplifies the complexity of the charging system

http://311s.org/tech/electrical/singlewire.html

[spl310]

Frank,

Welcome to the fray! A couple of things come to mind here. First, download the proper wiring diagram and enlarge it to make life better. Next I suspect the regulator. I have a couple of proper alternators for your car if you think that yours is wrong. Are there any markings on it that you can find? Should be on the metal plate on the top rear.

Here is the link to the diagram:
http://www.311s.org/tech/electrical/wir ... 671600.pdf

I still think that the regulator is doa...

[keith0alan]

One cause of this problem is a bad connection between the alternator and the voltave regulator. One of those wires, I think it is the white, is the voltage sense for the regulator. If it is missing or has a bad connection the regulator will run the alternator full on. Track down the wires and check the connections. On mine it was a corroded connector in one of the plugs. Sounds like in your case you might have shorted or broken wires.
keith

[Linda]

Frank,
My .02 cents is before you replace or rebuild any components, thoroughly check, clean, recheck, reclean and retighten all plugs, grounds, fusebox and fuses. Just go around and see how many places there are to clean and then clean them. It is not uncommon for them to be loose and/or corroded. BTDT. The ground by the alternator to the frame especially shoud be removed and cleaned, along with the spot on the frame, to bare metal. It was recommended to disconnect the battery neg first.
Like the lube points, it is amazing how many electrical connections there are to check on these cars. The wiring harnesses are expensive so you don't want to melt them (not to mention having an engine fire)
If you search the forums you will find lots of helpful pics and info.
Also, can we see a pic of your car? Never too early to start showing it off!
Good luck,
Linda
68 1600

[DatsunBucky]

I'd have to agree with checking the wiring first. If you had some overheating at the voltage regulator, then there's a good possibility that something else got way hot somewhere else in the wiring.

[S Allen]

See what did I tell? Lots of people willing to help out. Frank sent me a picture of his car. I need to downsize it for his avatar. Did you register in the registry already Frank? Too much stuff going on at work to remember everything. Any ways, welcome and pay attention to what people are saying. Good advice as always. See you at Road Atlanta.

Steve