Alternator question

My alt is putting out over 15v but less than 16v at the back stud on it. Is this to much as I have a MSD ignition and do not want to cook anything.. I do have a voltage regulator on the car and it is new.. Just don't want to mess things up.

Too much. Likely a bad ground connection or faulty regulator

I have a ground from the block to the frame and the battery is in the trunk and the ground there is to the frame also.

This is the voltage on the stud at the back of the alternator before it goes into the car to the regulator.

It should not put out over 15 as the only time it gets near 15 volts is in real cold weather. Check the voltage at the battery post with the car running and all accesories turned off and at about 1500 rpm. Then check it at the alt output post as they should be close within .5 volts. Then turn everything on like heater on high and high beams and see what it reads at both. If its much higher at the alt post then at the battery you may have to much voltage drop in the output wire back to the battery and over to the regulator. But first I would check it at the battery and see what that reads. It could still be the new regulator is bad as I have seen that before also. Ron

As said likely the reg. What is the sense voltage at the reg & I'm assuming the reg case is grounded well. Batt cables of adequate gauge? Recent problem or from day 1 since built? EDIT batt fully charged & batt is good?

I agree with RR.Check the batt and the ground at the reg.Also check the volts at the batt as suggested.Rocky

Thanks everyone.. I will try that. As far as I know it was from the PO... I just got the car last month and I am trying to get it back on the road again.

How good is your voltmeter? Check the battery voltage with the motor off, it should be higher than 12.25 up to 13.1 if just charged, and then start the motor, put the carb linkage on fast idle and check the battery voltage agian If it exceeds 14.9 V then look at what is causing the over charge

so take these readings.

battery pos to neg off, and running around 2k rpm.

sensing line to the voltage regulator (pos) to block (neg) running at 2k rpm

Back of the alternator (pos) to block (neg) same place you touched for the regulator if you can, also running at 2k rpm

the first one is to see how close your meter reads to what is expected.

second is to see what voltage you are getting back at the battery.

the 3rd is the voltage from the battery to the vr.

if the 2 are very different, it may be causing your charging problem.

if they are not, but you still overcharge, then you need a better ground on the VR.