75 amp fuse keeps blowing

[ziptiemechanic]

So every time I try to connect the positive connection to the battery it sparks. Already blew one fuse. I checked all the ground to make sure they were good and just replaced the broken plastic spacer for the alternator. Alternator is connected properly. The battery is a duralast miata battery. I also extended the wires that connect to the positive battery connector from the fuse box. I used wires from a 96 maxima and spliced the wires using copper wire splice connectors. I've also done a search, but all the post do say what actually fixed it. I'll take some pictures of all the connection when I get a chance.

[tossaxe]

Don't take my word for it but maybe you should look for a bigger fuse. I blew three 80A with no electrical problems in the car. As advised by a local electrician and mechanic I trust I've installed 100A fuse on teh battery cable. Running fine

[JDMRIDDAZ]

check positive connector on alt
theres supposed to be a plastic washer on it to shield it from ground
if its not there thats wat happens

[ziptiemechanic]

Ya the plastic washer/insulator is installed. I look into using a 100amp inline fuse.

[Darren]

DO NOT put a bigger fuse if you're talking about the 75A main fuse... unless you like fire :P

There has to be something wrong with the power wire, is the battery relocated? maybe something has cut through the jacket of the power wire and it's grounding out, causing the sparks....

Fuses are there for a reason, unless you have some crazy draw in your stereo or something, don't increase their size, or you will have a bad day when they don't work as expected.

[WIKID S4TEEN]

^^ bad day to say the least. You're not gonna be able to ziptie your way out it, lol.
I would check/test your alt to start with. Also any wiring that you might have modified or disconnect/connect recently. Because sounds like you have a short.
But for the love of God, please don't go increasing the amps on your fuse.

[GoodieGarageLA]

ghetto rig it and shove a copper wire into the terminals on the 75A fuse…

jk, man electrical problems suck, the 75A fuse for the alternator i think it is blew out on me today, cleared the bad ground now just gotta pick up a new fuse. rolling with no working interior electronics (gauge, radio, blinkers don't work) right now :/ lol

[jr_ss]

You're blowing that fuse because you have too much resistance in the wire you "spliced: together... You need to make that one wire, from one end to the other, not two seperate pieces.

[ziptiemechanic]

You're blowing that fuse because you have too much resistance in the wire you "spliced: together... You need to make that one wire, from one end to the other, not two seperate pieces.

It's two seperate wires coming out of the fuse box. If I connected them together into one wouldn't it be the same end result? One of the connectors is a bit corroded. I'm gonna go snatch up another one and see if makes any difference


Not my car, but this is what the two connections into the positive battery connection look like in the top right. Picture from phase 2 motorsports.
http://ep.yimg.com/ca/I/phase2motorsports_2230_95762141


Also the harness I'm using is from wiring specialties, both the engine and lower.

[ziptiemechanic]

Also when I connect one of the two connectors(the non corroded one) to the positive battery connection it doesn't blow the fuse, but when I hook up the other it sparks when I try to connect to the positive battery terminal. So I'm hoping the corroded one is causing the problem.

[jr_ss]

Alright, so you connected the both together and added another piece of wire to extend them? Because that's how you made it sound in your original post, that you spliced two wires together to lengthen them... Post s picture so I can get a visual.

[The Dude]

Correct me if I'm wrong but increasing resistance would not increase current, so it should have nothing to do with your splice unless it is shorting out on something...

[jr_ss]

Increased resistance is one of the things that causes fuses to pop, melt, or any other means of self destructing.

[Darren]

Increased resistance is one of the things that causes fuses to pop, melt, or any other means of self destructing.

While true, it's unlikely that merely increasing resistance in the wire will cause it to spark at the battery terminal.

Sounds like the "corroded" connector goes to a line that's grounded somewhere... or shorting (same thing)

[The Dude]

Are you connecting the positive cable or the negative cable first? If you're connecting the positive cable first and its sparking then I would guess you have a short somewhere.

[jr_ss]

While true, it's unlikely that merely increasing resistance in the wire will cause it to spark at the battery terminal.

Sounds like the "corroded" connector goes to a line that's grounded somewhere... or shorting (same thing)

Obviously it's not going to cause the cable to spark once it hit the battery, but it would explain his fuse blowing.

I have had instances where connecting a cable to a battery has sparked, but it is generally a small one and has never blown a fuse...

Stupid question, are you connecting the right terminal to the corresponding one on the battery?

[ziptiemechanic]

Yes the connections are connected to the correct battery post. I've actually solved the problem and it was looking right at me. The connection for the post on the fuse box never connected. It was tucked underneath the intake manifold. Now its connected, no sparks, no blown fuses. The worst thing is I looked right at the post and didn't even think anything about it.