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1999 Wrangler TJ 4.0.
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Discussion Starter · #1 ·
Hi, all!

I have a big 3 kit that I'm looking to install in my TJ. Quality stuff, 1/0 gauge, oxygen free, etc etc. I started googling and, like every Jeep project I undertake, it's more complicated than I expected.

It looks like one of these wires needs a fusible link. This is a bit annoying since it seems I'm losing some of the value of using 1/0 wire by bottlenecking. From what I've read it's not ideal to use fuses in place of a fusible link. So I guess I'll make one.

Questions:

1. Can I use the "4 gauge smaller" rule and do a fusible link at 4, or does it need to be the same size as the fusible link on the current wire?
2. Do I just use specialty fusible link wire and crimp it to the big wire, or do I need to something special there?
3. I can just piggy back the wires over the stock ones? I read this back and forth on this, so I'm curious what feedback anyone here has on it.

Thank you all for any input!
 

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I鈥檓 not sure I understand your questions, but you are not loosing any value by using a fusible link. Also, you will want to use appropriate gauge (and length) fusible link wire, not just smaller gauge battery wire.
 

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Discussion Starter · #3 ·
I鈥檓 not sure I understand your questions, but you are not loosing any value by using a fusible link. Also, you will want to use appropriate gauge (and length) fusible link wire, not just smaller gauge battery wire.
Well, from what I've read (I'm not well read educated on electrical theory) the point of using bigger wire is to increase capacity. Going to a smaller gauge of wire means it's a bottleneck. It might not matter in the grand scheme of things but it still bothers me 馃槀

1. From what I've read the general rule of thumb is that when you use a fusible link you're supposed to go to gauges lower than the wire you're putting that link in. I have 1/0 gauge wire for the upgrade. Should I use 4 gauge for the link or should it be the same size as what's in the factory wire? I'm thinking in lines of if I wanted to replace a fuse I wouldn't base the value on the wire but on how much amperage I'm wanting to protect against.

2. Since fusible link is something different is there something special I want to attach it to the larger wire with or would some kind of barrel crimp connector work?

3. A lot of write ups for the big 3 Upgrade recommend just attaching the new wires on top of the old ones, so not replacing, just augmenting. In some of the write ups they even use the same ground connections. I just wonder if this is what I should do or if I should just remove the factory ones and replace them completely with the new ones.
 
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I got the Zen 1 Gauge Big 3 cable kit from custombatterycables.com.
They include the fusible link, which goes on the alternator to protect your electrical system.
The battery cables are 1 gauge. The Alternator cable with fusable link is 4 gauge.

I really like the upgrade!
 

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Discussion Starter · #5 ·
I got the Zen 1 Gauge Big 3 cable kit from custombatterycables.com.
They include the fusible link, which goes on the alternator to protect your electrical system.
The battery cables are 1 gauge. The Alternator cable with fusable link is 4 gauge.

I really like the upgrade!
Awesome! Have you noticed any improvements in your Jeep from it?
 

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1 gauge wiring in the battery circuit is truly excessively oversized and of no significant benefit. Not even a Warn winch, which can draw well over 400 amps, comes with bigger than 2 gauge wiring. There's no benefit to paying more for that big of a gauge in that circuit. Yes you want a fusible link in the alternator charge circuit. It handles a surge better and won't blow prematurely like a fuse will. The factory fusible link in the alternator charge circuit is nothing more than a 10 gauge wire crimped into a 6 gauge wire.
 

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I would not double-up your red wires, 1/0 is more than enough. I use 1/0 from the battery (all the way in the trunk) to my high torque starter, and it turns my high compression motor without a problem.

You can have as many extra grounds as you like, no harm there.

You want to use fusible link wire rather than just smaller primary cable, the shielding is made to prevent fires. Regular crimp methods are fine.

Unless there was a problem with your stock wiring, you should not notice any difference with the new setup.
 

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Discussion Starter · #8 · (Edited)
1/0 gauge may be excessive, but I got the full big 3 kit for $40 through my company, which was cheaper than buying a smaller gauge from somewhere else. Even if there's no huge benefit from this size it was worth the $40. It's high quality wire, too. Stuff used for audio competition.

Thank you, Jo3! I'm going to get fusible link wire, but what gauge should I use? 4 gauge work? I appreciate your input. You as well, Jerry, as always.
 

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Larger gauge cables (lower number) allow more draw before failing (burning up). So I would recommend the stock gauge for the fusible link unless you have a specific need to allow more current. I think Jerry said that stock is 10ga, so thats what I鈥檇 recommend. 4ga would absolutely work, but it is oversized.
 

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Discussion Starter · #10 ·
That's what I was thinking. Shame to cut down on the bandwidth of that cable, but better safe. Wish there was a way to get away from that fuse link entirely.
 

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Awesome! Have you noticed any improvements in your Jeep from it?
Could be simply due to new cables and clean connectors after replacing, but the starter did seem to crank with a more authority. Very happy with the set. No problems with anything. I like having the military clamps on there for any future accessories.
 

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That's what I was thinking. Shame to cut down on the bandwidth of that cable, but better safe. Wish there was a way to get away from that fuse link entirely.
you arent losing anything by adding a fusible link. even if you upgrade to a 160a alternator, the OEM wiring is not the limiting factor. it simply prevents the alternator from taking out your wiring in the event of a failure. anything that you connect to the battery will receive the same power with or without a fusible link. you can do away with the fusible link, but you then run the risk of damaging your electrical system which could end up costing quite a bit to replace.
 

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Had Jeep engineers been able to get by without things like a fusable link, they would have definitely left it out to save money. Let's face it... Management at the big 3 auto makers had the screws to engineers more than ever during that time. Keep costs low and only include what is absolutely necessary for the operation and basic safety of the vehicles. Even then, cut the costs deeper for more profitability. Ahhh... Safety, schmafety! We'll fix it later.

The original wire to my 05 alternator looked to have been factory original. It worked fine for over 15 years, but I just wanted to upgrade the wire set and be done. I had already had two no-crank/no-starts prior to the new cables and new AGM battery I put in. I have not had any starting or electrical issues since. Should be set for a while.
 

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Discussion Starter · #14 ·
you arent losing anything by adding a fusible link. even if you upgrade to a 160a alternator, the OEM wiring is not the limiting factor. it simply prevents the alternator from taking out your wiring in the event of a failure. anything that you connect to the battery will receive the same power with or without a fusible link. you can do away with the fusible link, but you then run the risk of damaging your electrical system which could end up costing quite a bit to replace.
Well, if it's not bottlenecking then I won't complain. I found a 10 gauge 1' fusible link wire on Amazon for $10, so I'll just go with that. I'm looking into one of those 160 amp alts, maybe a Mechman 240 amp alt, so I'd rather get everything set up properly now for those down the line upgrades.

Had Jeep engineers been able to get by without things like a fusable link, they would have definitely left it out to save money. Let's face it... Management at the big 3 auto makers had the screws to engineers more than ever during that time. Keep costs low and only include what is absolutely necessary for the operation and basic safety of the vehicles. Even then, cut the costs deeper for more profitability. Ahhh... Safety, schmafety! We'll fix it later.

The original wire to my 05 alternator looked to have been factory original. It worked fine for over 15 years, but I just wanted to upgrade the wire set and be done. I had already had two no-crank/no-starts prior to the new cables and new AGM battery I put in. I have not had any starting or electrical issues since. Should be set for a while.
Didn't realize that about the engineers during that time, hopefully they didn't cut too many corners on my daily driver 馃槀. I've had problems with starting, though I'm starting to suspect something in fuel delivery. If I turn to key to acc twice to let the pump run it starts faster, but sometimes still struggles. It's cheap and easy to do the Big 3, and I'd like to replace the battery cables soon as well.
 

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Didn't realize that about the engineers during that time, hopefully they didn't cut too many corners on my daily driver 馃槀. I've had problems with starting, though I'm starting to suspect something in fuel delivery. If I turn to key to acc twice to let the pump run it starts faster, but sometimes still struggles. It's cheap and easy to do the Big 3, and I'd like to replace the battery cables soon as well.
That's a failed/failing check valve on your fuel pump. The fuel pump will need to be replaced to fix it. Everyone seems to recommend getting the Bosch fuel pump and to stay away from anything else. It's about $50 for the pump off Amazon.
 

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Discussion Starter · #16 ·
That's a failed/failing check valve on your fuel pump. The fuel pump will need to be replaced to fix it. Everyone seems to recommend getting the Bosch fuel pump and to stay away from anything else. It's about $50 for the pump off Amazon.
Yeah, I was a little worried about that. If it weren't for the huge plate of armor under the fuel tank I would consider dropping it myself, but I think those bolts are frozen at this point.
 

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Yeah, I was a little worried about that. If it weren't for the huge plate of armor under the fuel tank I would consider dropping it myself, but I think those bolts are frozen at this point.
After snapping two, I had to go nuclear and come in from the top. I jacked the body off the frame. Caution: I did not loosen or remove the very front body mount bolts. My front fenders "flexed" a little when I had the back end jacked up. No permanent damage... Everything flattened right out when I dropped it all down again. I was desperate to get to work next day. This was the only way for me to get it done in time.
4520097

Plenty of room to pull the pump assembly out... (new one installed in photo below)
4520098
 

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Discussion Starter · #18 ·
After snapping two, I had to go nuclear and come in from the top. I jacked the body off the frame. Caution: I did not loosen or remove the very front body mount bolts. My front fenders "flexed" a little when I had the back end jacked up. No permanent damage... Everything flattened right out when I dropped it all down again. I was desperate to get to work next day. This was the only way for me to get it done in time.
Plenty of room to pull the pump assembly out... (new one installed in photo below)
Okay, this is absolutely what I need to do! Mind if I ask a little more detail of how you did this? What did you have to unbolt to get the frame to separate like that?
 

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If your TJ is a pristine museum piece, then this operation may not be for you. I did this out of desperation and my TJ has scratches, lumps, bumps, dings and dents. While I first freaked-out a little, when I saw the front fenders flexed in the middle and the possibility of being creased in the process, I forged ahead and did what I had to do so I could get to work the next day.

I loosened 2 and removed 4 body mount bolts. Three on each side. Removed the mid-frame mounts and the rear mounts near the back bumper. Then, backed the ones right behind the front tires way out, but not removed. I wanted to have those ones behind the wheels threaded in just enough to keep the body from sliding off to one side or the other while the back end was jacked up.

I did not loosen or remove any bolts ahead of the front wheels. Since they were still attached and the fenders were still attached to the tub, the fenders flexed and dimpled in the middle a bit when I jacked the body up. Mine flattened right out when I lowered the body, but I cannot guarantee your fenders would do the same. Warning: You could damage your front fenders. I drew a red line on the photo to show the deflection.

4520162


I did not have time to drill out all the tank skid plate bolts and replace them. 1) My TJ was my transportation to get to a hardware store, and 2) I did not have the luxury of time to go that route.

Not for the faint-hearted or anyone looking to keep their TJ in like-new condition... This worked fine for me and got me back on the road in time.

P.S.: Double check body mount bolts. I missed tightening one back corner. I must have left it hand tight and missed it in my rush to finish everything up. Yeah... That bolt fell out on a bumpy road somewhere and is long gone. All the other ones were tight. Lesson learned.
 
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