For anyone that's having any sort of ( hard to diagnose) starting issues, or even for those that aren't, it's a good idea to add additional grounds to your Jeeps battery. The age and condition of your Jeep as well as added aftermarket accessories like winches, lights, etc... may make this modification especially relevant. Intermittent no-start issues can come from a variety of sources, but regardless of the cause, adding another grounding contact ( or 2 or 3 or 4) can't hurt and might even prove to be the solution.
You can easily make your own custom grounding cable or you can have one ( or several) made for you by a shop that specializes in auto parts, small engine repair, hardware, etc.
The most expensive part of doing it yourself is the recommended tool that you need to use to crimp the ends to the cable(s). If you decide that you want a good quality manual hydraulic press ( hard to justify unless you plan to use it a lot) then you can pick one up from companies like www.greatstuff.com
for about $125. These presses will provide the most solid and reliable crimp. You can also find cheaper crimping tools for around $25 that will peen or crimp almost as adequately as the more expensive hydraulic presses. In a pinch you could just use a bfh or sledge but that method isn't the best as the cable will only be pressed flat, allowing the cable to pull out of the end. Whatever route you plan to go, those are your options.
First you want to choose the routing and length of cable to be used. Use a tape measure to map-out the route that you plan to run the cable. Measure a few times and account for possibly having to redirect the cable around, behind, over, or under something. Obviously better to have a few to many inches than not enough. Keep in mind where you will be securing/ zip-tying the cable since you don't just want it to be loose and randomly flopping around. Make sure that it's going to be out of the way of anything like the serpentine-belt, fan, manifold, cat, etc.
Once you have your length and routing figured out, you need to decide on the gauge to use. My personal thoughts on this are listed below:
* 2g = a little on the "overkill" side of things but I'm sure that some people would recommend that size. I personally feel that it's a little bulky and hard to work with and may make routing more difficult.
* 4g = the ideal size in my opinion. It's plenty thick and is relatively easy to work with and to route. I don't see any reason ( especially with adding several grounds) that the 4g cable isn't up to the task.
* 6g = too small for the application. This gauge ( or anything smaller) should only be considered as offering minimal benefit as an additional grounding lead. I would steer clear of 6g or smaller.
Now you have the length, the routing, the crimping method, and the gauge figured out. All you need now is to determine what size lugs you'll need. Lugs are the copper ends that get crimped onto the cable. Do not use anything but COPPER LUGS... not terminal adapters, or rings, or forks, etc. What you need to determine what size lug to go with is 1.) what gauge cable you will be using, and 2.) what size bolts ( attachment points) you will be utilizing. Your choices are listed below:
* 2g cable = lug-eye dimension of 1/2", 3/8", or 5/16"
* 4g cable = lug-eye dimension of 3/8", 5/16", or 1/4"
You can always drill out the eye if it's too small or add a washer if it's too large but at least try to get the eye as close to the right size as what you need. 1/4" is pretty damn small and 1/2" is pretty damn big. Since this is a custom configuration, you can always do something like a 3/8" on one end and a 1/2" on the other... Whatever works for your particular application.
Now all you need to do is to buy the crimping tool and do it yourself or take your specifications to a shop that will make it for you. The components ( without the crimping tool) should run you anywhere from about $10-$15. The labor should be free of charge. You can't beat that for added insurance and/ or a possible fix for your intermittent starting issues.
My particular custom cable = 4 gauge/ 3.5 ft/ 3/8" lugs. I routed it from the negative battery terminal along the firewall to the top bolt on the alternator ( sandwiched between the top bracket and the actual alternator housing). Used about 4-5 zip-ties and a ratchet-wrench with the right size sockets and the job was done. Took all of 20 minutes.