So I have a weird issue that I just can't for the life of me figure out.
I bought my '92 Loyale a few months ago. 118k miles, and I had been driving it regularly. It got cold a few weeks ago and when I tried to start it I could hear what I think is the fuel pump (not sure that's what it is), but when I tried starting the car it wouldn't turn over the starter (I could hear the relay click). Not a weak battery sound (not the "click click click") just nothing at all.
The next day it was warmer and started right up.
A few days after that I got in to try to start it up and as soon as I switch the car to "on" I get a complete power loss. Dome light and dash lights go out. If I wait 5-10 minutes I'll get my dome light back. I've checked the batter and I get 12V+ on the terminals. I've tried hooking up my battery box (that will start my 4.0L Jeep that currently doesn't have a battery without an issue), but the extra juice doesn't do anything.
We had a 50 degree day here recently, and I thought maybe my issue was temperature dependent, but even on that day it presented the same issue.
I'm at a total loss here as to what could be wrong. I'm not even sure what to check next! Any thoughts as to what I could check to try to diagnose what is happening? The fact that I eventually get enough power back to run the dome light confuses me. Something gets energized which causes the problem, and it must eventually get discharged which allows power to return to things like the dome light.
My thoughts:
1) Bad battery (internal components), so even though it reads the proper voltage something else is wrong once there's a draw on the battery
2) Bad alternator, somehow gets energized and shorts out the electrical?
3) Bad starter? I doubt this because it happens even though I don't even try to start the car?
4) Bad ECU?