75 amp alt fuse keeps blowing

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danshaz82
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as the title states, the 75 amp alternator fuse keeps blowing. i have a 93 ka in a 90 chassis if that matters or not. i have searched, but i didnt really see anything of much help besides pulling that harness. i also had none of these problems before i did the starter and intake mani.
my starter went out a few months ago. so i just replaced that last week. in the process i did the emissions removal, so i had my intake mani off and all that.

now i have everything back together. the other day i went to put the battery back in and the fuse blew. only thing that works is my headlights turn on and off. car runs as well.

so today i went and got a new fuse for it. and the second i put it back in, it blew in my fingers. now i have no idea wtf it could be. all the grounds i took off are all back on and everything is back they way it should be (i believe).

the only thing that i can think of that is causing the fuse to keep blowing is one of the grounds on the back of the alternator. i remember i noticed the nuts on it looked loose, so i tried to tighten them up, and the terminal snapped in half. i managed to find a nut that was the same size, so the ground is still on the back of the alternator. but it is touching the casing for the alt directly. idk if that makes a difference or not.
i also have seen people talk about a plastic insulator on the back of the alt. im not exactly sure what that is or where it goes.

idk what to do at this point. i have a new fuse for it, but im scared to put it in cause i dont want it to blow again.
sorry about the wall of text.


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PEZi
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danshaz82 wrote:all the grounds i took off are all back on and everything is back they way it should be (i believe).


i also have seen people talk about a plastic insulator on the back of the alt. im not exactly sure what that is or where it goes.
Check these in as much depth as possible. It has something to do with what you did when you re-wired it, it wouldn't just start doing this because you put in a new starter.

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allenms240
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You're in luck, I did this yesterday. What I did was removed that terminal line and took off that plastic clip to get more room on the terminal for the bolt. I put the harness (the ground looking one, but really it's the one that goes from the alternator to the battery, charging it.), bolted it up, and blew the fuse. You can actually ghetto rig the fuses to work again instead of blowing your good one, just take the plastic cover off the fuse, and push the broken pieces together.
Anyways, It's blowing because you DONT have that plastic clip, the lead IS NOT supposed to be touching the alternator as you mentioned it is. When you do that, it will pop the fuse. You need to find that plastic cap, or a plastic washer so that when you bolt the lead onto the alternator, the harness is only touching the terminal and NOT the alternator. Please ask questions if you have any, I'm sure I can answer them, I just did this yesterday lol.
Allen

danshaz82
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PEZi wrote:
danshaz82 wrote:all the grounds i took off are all back on and everything is back they way it should be (i believe).


i also have seen people talk about a plastic insulator on the back of the alt. im not exactly sure what that is or where it goes.
Check these in as much depth as possible. It has something to do with what you did when you re-wired it, it wouldn't just start doing this because you put in a new starter.
there were only 2 grounds that i actually removed. i looked at the one that goes to the block right next to the intake mani, and there was a little bit of wire exposed. i gotta tape it up tomorrow or something.
allenms240 wrote:You're in luck, I did this yesterday. What I did was removed that terminal line and took off that plastic clip to get more room on the terminal for the bolt. I put the harness (the ground looking one, but really it's the one that goes from the alternator to the battery, charging it.), bolted it up, and blew the fuse. You can actually ghetto rig the fuses to work again instead of blowing your good one, just take the plastic cover off the fuse, and push the broken pieces together.
Anyways, It's blowing because you DONT have that plastic clip, the lead IS NOT supposed to be touching the alternator as you mentioned it is. When you do that, it will pop the fuse. You need to find that plastic cap, or a plastic washer so that when you bolt the lead onto the alternator, the harness is only touching the terminal and NOT the alternator. Please ask questions if you have any, I'm sure I can answer them, I just did this yesterday lol.
Allen
this is exactly what i wanted to hear :biggrin:
ill have to see if i still have the old one. but the terminal that the ground goes over broke, so there is little room. there should be enough for a thin washer tho. if not, would i be able to move it to another spot on the alt?

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allenms240
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this is exactly what i wanted to hear
ill have to see if i still have the old one. but the terminal that the ground goes over broke, so there is little room. there should be enough for a thin washer tho. if not, would i be able to move it to another spot on the alt?


It's not a ground cable, It's the cable that actually charges the battery, grounding it out (like what you're doing now by having it touch the alternator, is blowing your fuse). Thus, you cannot move it to another spot. If the terminal itself (looks like a bolt protruding from the alternator, a nut holds the cable one) is too short, I'd probably say you have to get another alternator. That terminal is the only one you can use, you cannot move it to another spot, or, like I said, it'll short out.

You can try using thinner bolts on the cable, but whatever you do, make sure the cable is only touching the terminal, not the alternator( use a plastic washer or something of the like that won't conduct electricity, because that again will short out your fuse).

danshaz82
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well, i fixed the problem. it was exactly what you had said. so i put a piece of plastic between the connection and the alt casing and it worked perfectly. thanks a ton for your help. unfortunately, i now have a fuel leak haha.

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allenms240
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Hey I'm just glad I could help man. Just here to pass on what i know:), glad it worked out. I was just so excited when I read your post because I knew what it was lol.
Fuel leaks are a doosie, I got one, too lazy. I just put a max of 8gallons in my tank and call it good.

danshaz82
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allenms240 wrote:Hey I'm just glad I could help man. Just here to pass on what i know:), glad it worked out. I was just so excited when I read your post because I knew what it was lol.
Fuel leaks are a doosie, I got one, too lazy. I just put a max of 8gallons in my tank and call it good.
:rotfl well im glad some one was able to help, especially since this seems to be a common problem.
i went to test the leads for the fuse, so i had the key on, and i heard the fuel pump kick on, then i smelled gas and thought nothing of it. then when i got home from work i noticed a big puddle under the car. im pretty sure i just cracked the return line right under the filter.

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breadbox
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get all new lines, it takes like and hour to unbolt replace and put back the fuel tank. just don't forget the grommet for the gas cap.

danshaz82
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well i fixed it. it turns out it was just the metal clamp was loose that was connecting the rubber line to the hard line

angrypenguin182
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sorry to bump an old thread, but i figured its better to bump than create an entirely new one

allenms240 wrote:You're in luck, I did this yesterday...Anyways, It's blowing because you DONT have that plastic clip, ... or a plastic washer so that when you bolt the lead onto the alternator, the harness is only touching the terminal and NOT the alternator. Please ask questions if you have any, I'm sure I can answer them, I just did this yesterday lol.
Allen
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is that where the plastic washer would go? im gonna try and get my alternator swapped out b/c as you can see i stripped the stud, or does anyone know if i can rethread it?

danshaz82
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that black part that looks broken was the rubber insulator.
but for the stud, thats almost what happened to me, but mine broke. i temporarily fixed it, but about 2 weeks ago the temp fix crapped out, and in the process, stripped the stud. i ended up just putting in a new alternator

angrypenguin182
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yeah tomorrow morning i'm going to try adding some washers and maybe i'll be able to tighten it properly, if not i'll have to suck it up most likely and get a new alternator

thanks for the reply

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allenms240
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I believe that is correct.
If you do end up blowing a 75 amp fuse like that, Then try putting the plastic shell on the other way. I doubt it will because that looks correct. As long as the lead with the rubber boot IS NOT touching the alternator housing (Like it would be without the plastic shell), you won't be popping any fuses.

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maj Andres
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So let me get this straight...the cable going from the alternator to the battery was actually shorting out the alternator bacause the rubber cap was broken/missing? Since the whole alternator essentially acts as a chassis ground.

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allenms240
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The rubber boot, no. If you look at the lead on the alternator, it has a black plastic "spacer" on it. That's what prevents the wire from grounding on the alternator. Without that, the wire you connect will have direct contact to the alternator housing, which will ground out and short. The rubber boot on the actual wire is just to protect it from weather, other wires, etc, etc.

angrypenguin182
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Yup^^ I got my alternator swapped out, so all good for me now. However that plastic piece breaks by looking at it


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