Possible alternator problem? lights on dash stay on when ignition is switched off

I would start searching for loose or bad grounds. bad grounds will cause voltage to float in certain areas in which they aren't supposed to be. Its a pain in the ass.

I'm not near the car now, but I'm thinking a bit clearer today, you are probably right.

I'm going to try the following
- disconnecting the ignition switch and seeing if the dash lights go out
- disconnecting the leads of the alternator and again, seeing if the dash lights go out

Will report back.

an alternator really has no involvement with power being fed with the ign off. It just maintains the battery with engine running. You have a parasitic draw that is draining your battery, as in, something is staying on with the ign off. A bad ign switch could very well be the issue. Or, there is something aftermarket wired incorrectly and is feed backing into the harness, powering up a main fuse, and keeping things on that way.

If you're dead set on thinking an alternator is the issue, unplug it first and see if anything changes. If not, and unplugging the ignition doesn't change anything i'd suggest googling how to do a parasitic draw test or dark current test. Normal range on most modern cars is anywhere from .040-.025A (40-25 milliamps), so it should be quite lower on an old Z.

As an example, you could have an ECM's battery and accessory pins shorted internally, which means when the ign is off, the normal "memory" power supply is now energizing the ECM and keeping relays/switches etc on. Probably not your case, but just saying. There are tons of things out there that can cause a discharging battery, testing will be needed to isolate.

Once you perform the parasitic draw test, from under the hood, start pulling fuses until the draw goes to an acceptable range. Whichever fuse you pull that causes the draw to go away, inspect that circuit for shorts/aftermarket shit etc.

EDIT: i should probably read a lil better next time. If the battery lights are staying on the dash with the ign off, i believe the meter/lights operate by looking for a ground, or potentially a bad ground to the meter. Inspect for shorts to ground on those pins with the alternator unplugged (i doubt you have 2 bad alternators that cause the same exact issue).

My alternator pulls power with ign off too. When I na2t'd I crossed the alt wires and fried the diodes. Ended up hooking a relay to the alt so that it becomes "disconnected" when the ign is off.
No lights on the dash though.

Alternators can't "pull power" when the ignition is off. The alternator creates power when it is spinning. It does not draw power when not spinning. When you crossed the alt wires, you crossed the power leads to it, and that fried the diodes.

Get yourself an ammeter (current meter) and pull a fuse at a time and put your meter leads on each side (across) the fuse socket. If there is no current draw on that circuit, the ammeter will read 0. Put the fuse back in an go to the next fuse and do it again. Keep in mind, normally some fuses actually have some draw through them (like the clock, radio). Write down the ones with some current draw and when done, if there is a parasitic power drain, it should show up in your results.

I had a parasitic loss once and killed my battery a couple of times. Turned out my brake pedal plugs had just broken and my brakes lights would go on and off by themselves parked at night, killing the battery over 2 days. Cheap and easy fix.

If I'm not mistaken that is an issue with the ecu. Of the 3 connectors, Un plug one of the top 2 connectors to rule it out.