electric problem with the xj

hey ya all, it's been a while i come in here. well, i still got the same old problem with the XJ. After the heavy usages on the winch, my voltmeter goin wild, the reading between 9v-14v and once in a it feel like dying. and my pressure reading around 20psi-40psi.
i check under the XJ and found out the battery cable I used b4 were 4g!!! no wonder i mellted the ground cable. i change the battery cables to 2g and i also replace a new alternator and it still doing the same thing.
whenever i hit the brake, the voltmeter go down a bit, heater/ac on go down a notch, headlight turn on-go down a notch.
check all the cables/wires connect the alternator and the starter and everything seem to be ok. what else do i miss? while cruising down the highway it seem fine and once in a while it seem to be wanna dye on me.
she start up fine

pls help.
i been without her for almost 1.5 month and miss her much.

thanks in advance



spec;
88XJ Laredo(power loaded)w/ 4.0L 205k miles(rebuilt on 199k bored .03 on block)stock aw4, stock np242, optima red top battery, autozone duralast gold alternator and starter

so im not the only one? wow i have had the same exact scenario with mine for almost 2 months. i feel your pain. someone please help us!

what years are we dealing with? on my '90 I placed an extra ground ( 4 gauge) from the neg. post to a body bolt on the rad support. ended all my dim and fluctuating light and gauge problems. I don't have it bookmarked, but there is an article out there somewhere that I followed. just make sure to clean off the paint around where you attach it to the body. see your ground strap at the back of the valve cover? thats your body ground. pathetic, isn't it!

thanks maybe ill have to try that . by the way mines an 89 cherokee

Craig H in Washington feels the wire from the alternator to the vehicle electrical center is under-sized, and he has a write-up on upgrading that.

http://www.olypen.com/craigh/charge.htm

Be sure to read it all. The OEM wire is a fusible link, so if you replace it with a larger wire you MUSTinstall a fuse. I went to a marine (boat, not Uncle Sam's Mountain Climbers) store to get the fuse Craig mentions, but more recently I've seen them in the electrical section at Auto Zoned.

actually,I replaced the alt. wire with 4G as well. put in a 100 amp fuse with its own block. replaced the battery cables with 2-0 welding cable and hooked 'em to military style clamps. jeepers creepers sells it without the alt wire for $100 US cost me $80 CDN starter spins way faster! volt gauge over 14v exellent upgrade if you can do it yourself