Giant spark while connecting battery

[Deimos]

Hi everyone,

I have a 240sx with a sr20det swap and recently i changed out my alternator. After installing it i went to connect my battery and give it a try, however once i connected the negative wire to the battery there was a big spark and the lights that always would turn on when i did this before changing my alternator were not turning on. If i left the battery connected after this spark the only thing that would work were my headlights. I could turn those on easily, but nothing else works, car wont start and i haven't got a clue what it could be.

Any advice would be much appreciated.


before install.

after.

[godrifttoday]

check your main fuse!

[muffler]

it could be grounding out on the alternator, make sure the positive is in the right spot, there should be plastic of some sort around it

[Deimos]

Originally Posted by godrifttoday

check your main fuse!

I did, I supose i should of mentioned this sorry, after i had connected alternator i didnt connect the grounding wire, i put it behind some other wires to get it out of te way while installing, and completely fogot about connecting it. infact it wasnt even connected before to my old alternator it was just bent towards it and touching the outside shell of the alternator. i had a duurrr moment, lol. anyhow so when i connected my battery i blew the fuse, i just bought two new ones, grounded the alternator and put fuse in and same thing happened as before, there was a giant spark and nothing besides head lights work, car wont start. Also new fuse is dead. I have one good fuse left so want to figure this out, lol. Is it possible i may have fucked up my alternator from not grounding it? or what else may i have messed up? I figured the fuse would of protected all that stuff like it is suposed to.

[Deimos]

Positive seems to be in the right spot

[91ka24]

You have the small ground wire on the alt in the wrong spot. Double check where u have it bolted. It's the 8mm bolt if i remember correctly. U most likely bolted it in a whole on the alt casing instead of the hole It's supposed to be.

[Deimos]

Originally Posted by 91ka24

You have the small ground wire on the alt in the wrong spot. Double check where u have it bolted. It's the 8mm bolt if i remember correctly. U most likely bolted it in a whole on the alt casing instead of the hole It's supposed to be.

I checked it, and yeah i have it connected on the outside 8mm bolt. I just brought in the alternator to get it tested so see if that got messed up and it tested ok. So i dont know what to do. I asked the guy from advanced auto what he thought, lol... just to get more opinions i know not to trust them. He was useless.

[91ka24]

Can u take a pic of how u have it hooked up?

[Deimos]

Originally Posted by 91ka24

Can u take a pic of how u have it hooked up?

Yeah i can i have to put the alternator back into the car first ill post a pic once i have done that.

[fliprayzin240sx]

Is it a brand new alternator? If its used, the plastic spacer from the positive might be fucked and the positive is touching the housing.

[Deimos]

Originally Posted by fliprayzin240sx

Is it a brand new alternator? If its used, the plastic spacer from the positive might be fucked and the positive is touching the housing.

Its new and the plastic spacer seems to be in place ill post pics soon.

[silver350z05rb]

If u connect the small ground backwards it will cause what you are saying.yes it CAN be screwed on backwards

[kennedy8383]

The alternator wouldn't have nothing to do starting the car.. It something else and the engine turning over or no? Have you check the starter working..

[91ka24]

He's not sayin starting, he's sayin when he connects the - it sparks like crazy. It's a alternator or ground issue

[Deimos]

Originally Posted by silver350z05rb

If u connect the small ground backwards it will cause what you are saying.yes it CAN be screwed on backwards

I read somewhere that that could be the problem, i believe i have it on right but wen i post pics u guys can let me know.

[ch1873857]

just had a similar issue with a buddies car. some weird weird electrical problems.. his starter was fried. after replacing the starter it still did it. so i unplugged his entire lower harness and put it back in. one plug at a time checking to see if the battery would spark after each plug was reinserted.

turned out. once the problematic starter was changed out and everything disconnected and reconnected everything worked fine. started right up.

my suggestion. unhook the starter and leave everything else connected.

attach pos. battery cable.

watch for sparks.

if it doesnt then you have a fucked starter..

[Deimos]

Ok this sounds like a noob thing to ask, ive got everythign installed again, im plugging in the clip on plug and theres an orange rubber thing that slides inside, is it supoed to be there? cuz its a bitch to plug in with it and it goes on great without. I was thinking maybe the last time since i had it in there it wasnt plugged in all the way?

[91ka24]

That's just a water seal to keep water from gettin into the plug. That's not going to cause your issue

[Deimos]

Originally Posted by ch1873857

just had a similar issue with a buddies car. some weird weird electrical problems.. his starter was fried. after replacing the starter it still did it. so i unplugged his entire lower harness and put it back in. one plug at a time checking to see if the battery would spark after each plug was reinserted.

turned out. once the problematic starter was changed out and everything disconnected and reconnected everything worked fine. started right up.

my suggestion. unhook the starter and leave everything else connected.

attach pos. battery cable.

watch for sparks.

if it doesnt then you have a fucked starter..

how will that tell me my starter is working or not if its not plugged in? just curious id like to know. and i dont think that is the problem because when i connect my negative wire to the battery nothing electrical works besides head lights. and i blow the fuse that goes from battery to alternator. The 75 amp one. Or does my starter have to be good for all electrical to work while car is off?

[Deimos]

Originally Posted by 91ka24

That's just a water seal to keep water from gettin into the plug. That's not going to cause your issue

ok pictures are up tell me what you think.

[91ka24]

U have that small ground wire on the wrong spot, u have it on the edge of the casing. that's not where it goes

[91ka24]

see on your first pic where it has the letters AT? Look left and diagonal, see that threaded hole? That's where it should go

[Deimos]

Originally Posted by 91ka24

see on your first pic where it has the letters AT? Look left and diagonal, see that threaded hole? That's where it should go

ok well thats good news, lol. im still confused how my old alt worked cuz that ground wire wasnt even attached so i just put it there kinda close to where old one was hanging, and that is an 8mm bolt so figured that was it... anyhow... it didnt come with a bolt to put into that threaded hole so do i go out and buy one? what kind of metal does it have to be and what should the length be, also what size is the hole? 8mm? and how is that spot differnet than the other, its all touching the outside casing? Im guessing the bolt that goes inside touches something that grounds it? im just curious... thanks or the help.

[OutlawLui]

Originally Posted by 91ka24

You have the small ground wire on the alt in the wrong spot. Double check where u have it bolted. It's the 8mm bolt if i remember correctly. U most likely bolted it in a whole on the alt casing instead of the hole It's supposed to be.

this is what im thinking, it looks like its bolted to the wrong spot

[91ka24]

just get a old bolt thats laying around lol doesnt have to be some special magical bolt lol

[Deimos]

Originally Posted by 91ka24

just get a old bolt thats laying around lol doesnt have to be some special magical bolt lol

ok illl let you know how it goes.

[Deimos]

Originally Posted by 91ka24

just get a old bolt thats laying around lol doesnt have to be some special magical bolt lol

Well it didnt work, my last fuse blew the second i connected the negative terminal.

[OutlawLui]

take it to autozone maybe something inside is the culprit

[Deimos]

Originally Posted by evilpanamajack

take it to autozone maybe something inside is the culprit

inside of what?

[OutlawLui]

Originally Posted by Deimos

inside of what?

something inside your alternator might be whats fucked up