97 wrangler charging problem??

You say you checked the fuses but did you really test the fuse LINK inline between the alternator and the battery? Should be a relatively fat colored segment of wire. It will be more flexible than the rest of the output wire from the alternator. Those things break by opening up, usually right at the crimp between the cable and the link or at the lug near the battery.

PS:

You might consider a portable battery pack for him - Harbor Freight has one for under $40 that I've used for several years. Sealed battery, holds a charge really well and has been really useful around here. No jumper cables to mess with, just clamp it on and go. Makes a good "stocking stuffer".

I didn't check the link, didn't know it existed. so its in the cable somewhere between the alternator and battery? I guess it could be checked just using a meter? I'll try following the cable and see if I can find the link. thanks cal

First thing I'd check is dead battery or battery cell. A dead cell can draw down the alternator so much it just can't keep up. Pepboys/Autozone can test the battery as well.

I'm planning to try charging the battery tonight, and getting it tested tomorrow. It's only about 4 months old, but I know it could still be faulty. thanks cal

While checking ground wires, i noticed the battery ground/alternator ground/and two other ground wires that come together at the engine are loose on the block. The way it is put together, the wires are actually tight against each other, but the stud into the block is loose on the block. (This stud also holds the dipstick tube..) I don't know if this would matter since the wires are actually together tight. I will clean all these 4 connectors, tighten the stud in the block, and then reassemble. Any chance this could be the reason the alternator doesn't seem to work? (I checked the same ground on my 97 GC and it is very tight against the block.) thanks cal

Floating grounds are ALWAYS a problem. Technically, if the alternator has a solid ground through a wire, it SHOULD work. But if the case is not properly grounded to the engine and then to the battery, the voltage seen by the regulator will float up, shuts off the alternator output.

A lot of speculati> >> >>

Thanks for all the replies. Too dark and cold outside now, so will try again tomorrow afternoon. cal

Gotta by an inline 6 - that @#$%^&* stud is a flaming bitch to work with! You'll need two wrenches or a wrench plus a good pair of vice grips and some luck since just trying to tighten it with the wires tight can twist and break the wires attached to it. You may be able to tighten it back into the block using the outside nut but I usually have to manage to get hold of the stud behind the connector lugs and loosen the nut off to get the stud tight. PITA!

Quick test: run your jumper cables between the battery negative and the engine block. If that gets the alternator up, then you found the problem. I forgot about that - my last bout with your problem was the fuse link but I've seen that stud loose before as well.

If you can, reattach those to the bolt that holds the coil to the block. Or the point just forward of the passenger side motor mount. I've started to put in a seperate ground strap for every I6 I help someone with as that is the #1 cause of engine problems.

This might cause some problems but genrally not charging ones. Floating ground to the block usually results in wild sensor/dtc errors and rough idle.

Thanks for all the replies! I'm not sure what the problem was, but the alternator is charging fine now. Cleaned all connections to the alternator, and fixed the ground problem. Just had autozone test the charging system/battery, and everything is good. thanks again cal

Wonder if it would be easier to fabricate a new ground jumper and use the engine motor mount bolt. Some of those blocks also have additional mounting locations on the block that just need tapping (or might already be tapped)

That or threaded rod, run it down into the hole then use a jam nut over a split washer to lock it in. Then bolt down the ground straps to that. A tiny bit of locktight will help and won't hurt the connection. It moves out of the way and most of your ground comes from clamping to the block.

That's close to what I do every time I have to pull one of those out. There is one nut down near the block but the lugs on the wires seem determined to freeze them between that and the top nut so the whole thing wants to turn. I do two things, actually: Locktite red on the bottom part of the stud and a lock washer under the lower nut. Still a PITA to get at but so far I haven't had one back out on me a second time. Biggest problem is that this stud is the primary ground for a bunch of secondary circuits so it affects a bunch of things.

My motor mounts already have jumper straps across them - was that someone's good idea or is it the normal practice?

One of the nice things about working with threaded rod is you can use vice grips to get it tightened in there then cut off the buggered up threads. The hardware store has some (not sure what to call them) but they look like threaded rod but have a hex socket in one end.

Dunno. Usually the jumper is from the stud to the frame. Still though it's not a bad idea. Next time I'm under the ZJ I'll add one to the passenger side mount. Fairly easy to get at.