My love-to-hate-it relationship with the Solstice continues.
I was having some issues with apparently-random warnings (ABS light, weird DTC, gas cap warning when the gas cap was not loose). The issues temporarily (for a few days) disappeared. Since an autocross last Sunday, I hadn't seen any weird behavior. (However, even though the ABS light was not on at the autocross, the brakes locked up a few times.)
Today, my CEL came back on. I hooked up the scanner:
0x7E8: P0171 - System Too Lean (Bank 1) (Pending, Current, History) 0x7E8: P0420 - Catalyst System Efficiency Below Threshold (Bank 1) (Pending, Current) 0x7E8: P0455 - Evaporative Emission System Leak Detected (gross leak/no flow) (Pending, Current, History) 0x7E8: P0507 - Idle Air Control System RPM Higher Than Expected (Current) 0x7E8: P0563 - System Voltage High (Pending, Current) 0x7E8: P0621 - Generator Lamp Terminal Circuit
I suspect a bad ECU. Even the alternator warning (P0563, P0621) appear to be harmless, since the battery is definitely getting charged. The car starts right up.
Oh, and I noticed yesterday that the tach doesn't really work for about the first 10 seconds after start. The needle just sort of bobs up and down about 5ish degrees.
Definitely some sort of electrical gremlin. :/ All the grounds I've checked have been fine, but there are a lot of them so it's possible I've missed one.
I pulled the alternator yesterday, and saw this. Not sure how I missed this when I pulled it off of the old engine. It's worth noting that the previous motor threw a rod from the #1 cylinder. I think the rod grazed the alternator.
Looks like there's a short in the coil.