Okay, okay. I should have taken the battery to the Auto store before asking everyone for advice, but, turns out I needed the advice just to override my sense that the battery was good, and to take the damn thing to the store. It didn't fire right up, but after a number of tries with a new battery and my truck on the jump, my old blue 240d fired up.

While I have you on the phone...

Should I try MMO to increase compression?

Thanks so much, all. I will in fact be reaming out the GP holes and testing 2 and 3, on account of the ohm problem. Thanks especially Kurt gastropodus for offering to come over and help, though with two babies, visiting in-laws, and everything else, I just couldn't reliably schedule it.