Black Positive Cable = FUUUCKKK YOUUU!

[mamzak]

So, I just went to pull my E30 out of storage, and COMPLETELY forgot that the previous owner had put in a black cable to the positive, and a blue cable for the negative. Long story short I hooked up the battery the wrong way, and it was hooked up for about 30 seconds, but ronchy smelling electrical smoke started pouring out of the engine bay. When I hooked up the battery the right way and tried to start it it wouldn't crank at all. Then I used a good battery and tried to boost it and it started, but as soon as I took the battery off the tach dropped to zero, and then the car sputtered and died.

I touched the alternator after and it was really hot, so that's what I'm betting it is, but has anyone else made this retarded mistake? What else could it be? The shitty part is that the car is 45 mins away in a quanset hut, so I can't experiment on it right now.

Any idea?!?

[Mossman]

I've done this before and actually didn't damage anything, I got lucky. People mention getting ABS lights after doing this cuz of a fuse, maybe the one integrated into ABS relay, blowing.

Anyways....if it starts then the starter isn't dead and I would look to the alternator. Trace all wires going to the + lug on the passenger firewall, focus on alternator though.

[5KWattson]

new harness, if it got passed your fuse blocks

[mamzak]

yeah I edited that... I touched the ALTERNATOR and it was hot.

It started once, but I couldn't repeat that result trying it again. I read that the polarity on the battery itself might have been reversed by doing this!? I have an Optima Redtop and it was kinda hot after the ordeal.

:( My poor E30.

[AndrewBird]

You more than likely fried the diode pack in the alternator and who knows what else. Expect this to be a HUGE pain to fix as tracing all the wiring to make sure nothing got burned is quite the undertaking.

[E30 Cabrio]

When charging, jump-starting, or swapping your battery always remove Fuses:
10, 12, 21, 23, and 27 beforehand.

Check those fuses to see if any of them are blown.
Replace any of those that are, then try starting the car again and see if the tach works and the cars runs.

And kick the PO in the nuts for wiring up the car that way.
My guess is he's an electrician, thus the Black wire for the +

[HarryPotter]

If you have a 325 and you did this I cannot wrap my head around how you would mix the two up regardless of wire color. Now on a 318 or a vert I could see this happening. But even then unless you were working in the dark the battery usually clearly marks negative/positive.

[Mossman]

When I did this I have even more reason than this guy, PO wired the positive black and the negative RED!!!!!!!!!!!

[mamzak]

If you have a 325 and you did this I cannot wrap my head around how you would mix the two up regardless of wire color. Now on a 318 or a vert I could see this happening. But even then unless you were working in the dark the battery usually clearly marks negative/positive.

No it's on a 318is, and it was in a quanset hut with no lights. :P

Arrgrhh. Stupid stupid stupid.

[87-325ic]

my parents did this to my car, but i got really lucky. it only shorted out the battery. and it was tried many many times. autozone replaced the battery free under warranty, which i was unaware of.
The ABS relay can burn its fuse if this happens, somehow mine didnt either.

i guess its cause i have a vert and i moved the battery to the trunk....
this equals a Black positive cable, and a Red ground cable. Isnt that awesome!??
i figured i'd be the only one ever jumping it. on the absolutely rare chance it ever needs doing.
guess i was wrong.

[Chabs]

that sucks dude. probably need a new alternator. don't feel bad though, I've had my share of fuck ups as well

[maniacmatt]

I am in edmonton also and have a spare alternator you can try. PM me if you need some help and I can give you my phone number.

You also could have fried your ECU, I unfortunately don't have a spare 318 ECU.

[mamzak]

For real!? wow! that's awesome man!

Ugh. I can't believe I did this, but yeah any help would be GREATLY GREATLY appreciated. haha there will be some beer in it for you! :)

[E30 Cabrio]

If you have a 325 and you did this I cannot wrap my head around how you would mix the two up regardless of wire color. Now on a 318 or a vert I could see this happening. But even then unless you were working in the dark the battery usually clearly marks negative/positive.

On Verts, the battery is under the hood and there is a short cable from the Neg - terminal to the body near the shock tower and the Pos + has a few other wires running to it so it would be hard to mix them up on a vert.

With a coupe and the battery in the trunk, it's sometimes hard to see where those cables are going.

[mikeedler]

being that it is a german car.... usually brown is the ground wire color.

sux for you. I would also bet on the alt. being bad now.