This sounds like a grounding issue, right? Car not starting, but getting power... until its not

Late Saturday night, I had to pull the $700 accord into the garage. I got in, turned the key, and as soon as I got to the cranking position on the ignition I immediately lost ALL power. Pull the key out, nothing. Go under the hood and tighten the negative cable on the battery. Interior lights come back on. Turn the key, same issue. Happened a couple of times until I finally got it to start (tightening/wiggling the negative cable between each attempt).

This morning I went to start it, and the same thing happened. I didn't have time to dick around with it, so I just had my wife drop me off, but I plan on addressing it tonight by cleaning the terminals and the connectors. Is there anything else this might be? Ignition switch or main relay?

FWIW, the battery has strong cranking power and when it did turn over it started immediately. The battery that was in the car prior to this was a marine battery that was 12 years old and completely dead, as in wouldn't even take a jump start dead.

My go to in a situation like that is typically to get the thing running, then wiggle every important looking connector and wiring harness until I get something repeatable so that I can start to narrow down the possibilities. Usually at that point the multimeter comes out, unless it's one of those wonderful situations where you can actually see the problem when you get close enough.

Agree to start with the simple stuff -- good, clean battery cables and grounds. I've seen bad batteries result in this behavior, too. That said, older Honda main relays are a known issue. Wouldn't hurt to have a spare on hand.

I'm not sure what the over/under is on a spare new part, versus 3 unknown parts the next time you go junkyard diving?

In reply to mtn:

My E36 did exactly that recently. Turns out it was the negative battery cable had corroded/failed. Biggest telltale was that after trying to crank a bunch the neg cable was hot to touch. Cleaning terminals may work, but if not then that might be your issue.

I've replaced terminals/connectors on battery cables many times. They get old, and sometimes even "tightened down" isn't really a good connection anymore. It's a $10, 10 minute fix that solves so many headaches.

Since wiggling the negative terminal on the battery fixed it temporarily I'd be pretty confident that repairing the connection correctly will fix it more or less permanently.

Time for a new ground cable. Problem is likely between the strands of the cable and the terminal, rather than between the terminal and the battery post.