Help: Battery Drains When Engine is Hot

[Loser]

Alright, I think I'm narrowing in on the issue. I drove the car to the auto parts store to have the battery and alternator retested. They tested the battery using the positive terminal at the fuse box and it failed. They tested at the battery terminal and it passed. I tugged on the wire at the fuse box a little and the car stalled. After starting and stalling the car a few times, it seems I might have two issues. 1. The wire to the alternator is shorting to something only when it's hot. 2. I hear a relay buzzing when I shake the fuse box. It turns out that the fuel pump relay will cut out just by jiggling it a little.
I am back home now, but on the way home the battery gauge showed around 8V and the check gauges light was on. The car ran though and the battery measured 11.5V with the car running. I hope I didn't mess up my new alternator.
Anyway, once the engine cools, I will redo all of the connections on the alternator and see if that resolves my voltage issue. Then I need to look into the fuel pump relay.

[pajeff02]

Swap the relay with a non-essential one if you run into trouble on the road. Not a bad idea to keep a spare in the glove box either. If you remove the wires to the alternator, check for corrosion and if you find any be sure to clean it good. Dielectric grease is a good thing to use on connections, especially if they are in moisture prone areas.

[Loser]

Problem Solved!

The positive wire terminal to the alternator had broken loose somehow. When I started to pull the alternator out, the bare wire slipped right out of the terminal. I cleaned the wire and installed a new terminal end, put everything back together, and went for a drive. The issue has been resolved.

As far as the fuel pump relay, it is not the relay, the issue is with the contacts in the fuse box. They are too loose. I bent the relay leads into a slight S shape and the contact is good now.

- Tom

P.S. Is there a way to change the title of this thread to include "Solved" at the beginning?

[pajeff02]

It's all good -- no need to change the thread title.

Nice work on the diagnostics and glad you got the problem solved.

[Firebirdjones]

Problem Solved!

The positive wire terminal to the alternator had broken loose somehow. When I started to pull the alternator out, the bare wire slipped right out of the terminal. I cleaned the wire and installed a new terminal end, put everything back together, and went for a drive. The issue has been resolved.

Ha, I mentioned it sounded like an issue between the alternator and gauge since the battery showed charging when tested with a meter. Silly little things like that can cause real grief. Easy fix though.