Voltage regulator help

Hey, I just recently installed a new set of VDO guages in my 67 mustang. The past few days I have noticed that my volt guage shows that I have around 13 volts at idle and when I rev up to 2K or 3K it goes up to 16+ volts.
So on my way home from work I picked up a new voltage regulator but that didn't solve the problem. Upon further investigation I noticed that there was not a wire connecting to the "I" terminal in the connector. I couldn't see a wire anywhere that was cut or anything. Is this my problem? Or is there something else? Also there are two wires that come out of the "A" terminal and one of them is just cut off a few inches away from the connector. What wire should connect to the "I" terminal? and what is this extra wire at the "A" terminal?
Also I did verify this with my voltmeter and my guage is correct. Any ideas?

I might have some references for that, but not in the house, and it's too late to go outside for them. The unused terminal might be for an idiot light.

You should probably double-check the true voltages at the battery with a voltmeter. The new gauge might not be as accurate as you'd like.

I'll try to find something on this tomorrow. If I forget nag me with a personal message.

Standard Ford setup for external regulator is F for field, S for neutral terminal on alternator, B+ for alternator output, and I for the idiot light. The idiot light circuit goes through a lamp with a 15 ohm resistor in parallel, via the ignition switch, back to the alternator output. If you have gauges you just leave that one unconnected.

If this is a mechanical regulator, there are some fine adjustments that can be made. I have a description of these, so if you need, I can scan, copy or whatever. But before adjusting the regulator I'd make sure that you have an accurate voltmeter, and that the battery itself is in good shape, because you can get some overvoltage issues if the battery isn't taking the charge as expected.

Thanks for the input. I guess I have no use for the I terminal.
My regulator is not mechanical. My battery is a brand new Optima redtop and although my DMM isn't the a great one; it was spot on with my volt guage as I revved the engine. Could me alternator be a problem here?

Thanks for your help.

REading up a little on this, it appears that a problem in the field circuit could cause overcharging even if the regulator is good. It seems pretty unlikely, but anyway, there's the possibility that short in the field (that's the rotor on an alternator) could cause loss of regulation. I haven't yet found a good source for the precise values you should get from the field, but it should be a simple ohmmeter reading across the slip rings. If I find a number I'll post it.

another book says you should carefully check the wiring harness to the alternator for shorts, etc. in the field circuit. It seems to be the consensus that if the regulator is known to be good and it's overcharging, there's something the matter with the field.

Thanks for the help. I will give it a try.

I think that I fixed it. Turns out that I have a bad ground on my alternator. The guy at autozone told me that that can sometimes cause overcharging. I thought that the housing and the mount to the engine block was the ground. Well I looked closer at the back and there was a bolt with a "G" next to it so I connected a wire from there to the engine block and now it doesn't go over 13V. Go figure. I will give it some time though, I only took it for a short test drive.