Guardian Angel watchin out?

they have a built in reversal relay circuit that will prevent anything bad from happening, in most cases. It's to protect the ECU primarily.

i say in most cases because if your alternator slowly starts to feed your injectors, ecu, and other accessories voltage up in the 18's or 19's, expect to replace a lot of things. when i had crossed my battery terminals like the drooling star-gazer that I decided to be that night, it fried my voltage regulator on my alternator. So instead of the 14ish volts it usually outputs, it put out 18+ volts, slowly killing each of my injectors, my vacuum pump, and an ignition coil or something else- I can't remember.

And thus, the 350z alternator swap was born.

My cousin was helping me install a battery in the 2+2 and shorted the hot to the plenum I think, zapped the radio, even though the fuse was intact it didn't work at all, not much else happened

But installing jumper cables in reverse would actually suck the voltage out of each battery in theory, it's probably ok, but like careless says pay attention to voltage and weird behaviour

Some noob in my auto class in high school hooked up a charger backwards and threw it on high amp start. Coincidentally the day I learned how to use a fire extinguisher.

These Z31s really were ahead of their time lol, I thought my car was done lol

Others have done this with a Z31 with bad results. Fried ECUs. You were just lucky

^ this

The first rule of jumpstarting another car with your Z is, to not jumpstart another car with your Z.

The last time i tried it blew a fusible link. Luckily i was at work and took it in and soldered it back together
until a replacement could be found.

If i were to do it again, i'd disconnect the pos or neg from the Z and just jump directly off the battery.
Having the motor running isn't necessary.

I ruined my clock and radio jumpstarting my sister's car with my Z. I'm just glad that's all that happened.

Reversed Polarity

I've had a similar situation with my Z. Had a buddy helping me work on the car. I asked him to put the battery back in…

My heart sank when it didn't turn on…

Then it just stopped when I noticed the battery was in backwards…

I re-installed the right way, and crossed my fingers. She started right up! All stock electronics were running fine, no issues. My headunit and subwoofer amplifier both blew fuses, and worked fine when replaced.

I had another amp that I was testing out in the car. It was a Brand-X 8 channel marine amplifier. This amp (which was supposed to have reverse polarity protection) ended up short-circuiting. I found out later that Brand-X is made by Pyle. This is a very big no-no in the car audio world! Never waste money on Pyle audio amplifiers. This one had horrible sound quality, poor grounding, and horrible design that picked up on alternator noise due to a lack of a regulated power supply (it was new, fresh out of the box). That being said, I ended up taking it apart, and found that the diode had blown, and I replaced it and got it working. It is now for sale, any takers? (and no, I can't actually sell crap to anyone without feeling bad, so it will be sitting here, getting poked at every now and then…)

Ebay man

I put on a battery charger and touched it to the wrong side once. Was only set to trickle charge at 2 amps though so meh, didn't do shit.