Voltage regulator overcharging

Phil21502 said

Ok checked with key on run from the positive post to where the blue wire attaches to alternator and got 1.5 volts. Next I tried the blue wire from voltage regulator to positive post and got the same voltage of 1.5 volts. Next I tried by unplugging the voltage regulator. I got .3 volts from positive post to blue wire on alternator. Next tried from positive post to the blue wire on the pigtail that goes in voltage regulator and got .3 volts. Any ideas? Getting around 15.25-16.00 volts at battery at idle

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That blue wire is tied into other parts of the harness via the crimp weld, so it doesn't surprise me that you get what could be considered strange readings.
Start by making sure the regulator is grounded really well, and if your car has the connector behind the passenger side cylinder head, clean the terminals for that blue wire there also.

Most likely what is happening is the your blue wire is telling the regulator that the voltage is too low and the regulator is trying to make up for it by charging more.
Once the regulator is able to see the actual system voltage without loss from bad or dirty connections your charging voltage may stabilize where it should be.

Some of us have moved that blue wire off the harness and connected it to the starter relay battery post with an ignition activated relay to alleviate issue's like that, so the regulator sees more accurate battery voltage.

A good positive ground for your regulator is the best place to start.