I got the Fastronix kit.

 

That is exactly what I did years ago with the Military terminals. Works beautifully, best damn battery terminals out there. I used to have battery issues like the OP when I first got my disco too. The factory terminals suck.

 

I agree with other members saying to check all of your wiring and connections to and from the battery are clean and tight.
Also check the fuse link in the engine bay fuse box for being loose or corroded.

 

Thanks for the suggestions, all. Cleaned up all of the grounds for the wire from the negative terminal to the body and the alternator bracket. Tried to start using the jumper cable as a ground from the negative terminal to the block, too.

I also took vice grips and squeezed in the battery terminal connections to get a better fit. It still won't start without a jump - just a single click and dim interior lights.

I'm leaning towards the starter as the bad component. My thought is that the starter is dying and is currently only able to spin when it gets 14v from a running donor car. Who knows how long it'll still be able to start on a jump, so I guess I'll park it until I'm able to get it home. Not sure this is a driveway repair that I can do while on vacation - the heat shield is rusted to pieces so that's not going to come out easily, and I don't have any jack stands or ramps to raise up the front of the truck. According to RAVE you need to disconnect the exhaust flange/front pipe, which isn't going to come out anytime soon. Any other thoughts on something I might be missing?

More bad news, to pile on: the boot on my passenger side lower ball joint is shot - it was just installed 3 months (2k miles) ago. Woof.

 

If you're vacationing near Philly perhaps I can help? Although that sounds like an oxymoron! A failed starter is hard to come to terms with however if you've ruled out everything else I suppose it could be a possibility. I've never seen one fail in this manner but I certainly haven't seen everything, either. Since it's been starting with a jump, what happens if you try and jump start it from a non-running car, just a second battery? Connected in parallel this would double your amps but probably still not come close to what an alternator is providing.

 

Thanks for the offer! Unfortunately I'm out on Cape Cod and had hoped to spend most of the week out on the oversand on the national seashore. The first time that it failed to start was way out at Race Point - about a 45 minute drive through sand trails (so I'm lucky that it started at all - that would have been a really expensive tow).

I had the same thought as you, and already tried starting it with a non-running car (after about 20 minutes of charging while the donor car was running, just in case my battery was low). No dice - just a click.

I agree that this seems inconsistent with what I've read re: starter failures, but I'm not sure that anything else really explains this behavior. The question is, really, how many times can I still start it up with a jump before the starter is completely toast and the truck is immobile.

 

Clean your battery posts and terminals extremely well. Does the wiring inside the cable seem swelled or look corroded at all? Replace them if so. These may not solve the priblem but when dealing with electrical, you dont go further until these items are perfect.

Have you load tested your battery while in the truck and before starting? You need to see if you actually have battery drain or if you solenoid/starter just need too much amperage to pull in/spin.

Do you have a DIGITAL MULTIMETER? I've heard no mention of volatges at rest or during starting attempts.

If your battery is indeed goung dead, then you can locate the drain... disconnect poitive cable, run meter in AMP setting between + post and + cable. Check amp draw... if it's above .1 amps or so after being of 10 or so minutes, you have an issue... track it down by removing wires or pulling fuses until it goes away... and when it does, you have located the problem circuit. It could also be alt main wire or starter cable that don't go to the normal fuse block... so if you pull each fuse and amp draw never changes those are worth checking.

The old "Dont connect at both posts of the battery" is a safety thing... batteries off gas explosive gasses. Connect positive first, then negative which can possibly spark and you might make a boom. As long as you don't explode it doesnt hurt a thing... but it's the reason you don't make your last juml starting connection at a battery post.

 

Similar problem on mine was a bad ground (-ve to engine). It didn't look bad at all but after cleaning it up my starting problem was resolved. It was so bad the engine tried to ground via the brake cable. Got so hot it welded itself. As these vehicles get older it's always good maintenance to check ground connections and clean them up. Trust me - replacing the handbrake cable is a bugger of a job.

 

Voltage while not cranking is at around 12.6. Alternator makes 13.7-14.2. Not sure about voltage while attempting to start, but can check this later tonight. I drove an hour to autozone and they did a diagnostic on the old battery plus the alternator. Both passed (they replaced the battery anyway under warranty) and the battery showed as 100% charged on the tool.

I inspected and cleaned up the battery terminal clamps, ground to the block at the alternator bracket, and the ground to the body (that connects from the negative wire going from the - terminal to the block). I can get some steel wool and try and clean it up further, but the contacts seem good. Also inspected the + and - connections in the fuse box, and they look to be in good shape.

Also tried to rule out a bad ground by substituting the negative cable for a jumper cable from the negative terminal to the block - no change.

I tried checking the draw on the battery using the multimeter but it wasn’t registering anything - not sure if this was user error or not.

edit: I remember seeing 11.5 on the Ultragauge when cranking, the first time this happened. I’ll confirm - I think I’m looking for 10.5 at least?

 

Also clean the starter terminals.