That extra small ground wire may be going to an added accessory. Not sure. Where is it going to? Have you traced it? Maybe part of a trickle charger accessory?

 

ECU is giving me zero codes. I put the key in, turn it to start, and the FI light turns off after 3 seconds, indicating no problems with the DFI system.

But, to close this thread and to thank all of those who contributed, I took the battery in to my local auto-parts store, and when your battery's voltage (12.7), is higher than its cranking amps (7), you ain't going anywhere. Bought a new battery, and I'm back in business.

K.I.S.S., I know.

Thanks to all who have contributed, and my apologies for a less-than-glamorous end to this story.

But hey, at least I finished my Spring check-down early this year.

 

hahaha, congrats on the fix