Still no fire. So I rebuilt the harness with 10 gauge wire for the 12v and ground circuits, with the 10 gauge tied to the positive terminal and run through a relay that is controlled by switched 12v from the diagnostic port.
Then I tested resistance on the coils individually, and compared that to resistance from the connections to logic level outputs, and I have continuity through those circuits. So I tied signal ground to the EZK's internal ground, no change.
I tested the board with a DVOM, and I've got 5v to the board, and a good ground, which leads me to suspect the spark output. I believe it should be a 5v output, but I'm only getting around .3v to the board. I read here
http://www.atmel.com/Images/doc7607.pdf that minimum output high voltage for the Atmega controller is 4.0v, so it should be sending 5v to the coils, but it's not.
So I think I might either a bad board or a bad solder to the spark output on the EZK; I'll check it in the morning.
So I looked and the IC on the board is attiny24a, and its dc characteristics are listed here
http://www.atmel.com/Images/8183_105.pdf
The attiny24a needs to see .6v to pull the circuit high if supply voltage is 2.4-5.5v; from the spark output, tested on either side of the resistor and at the wasted spark board, I'm only getting about .5v. The wasted spark board is outputting .3v consistently on both spark outputs. I don't think I'm going to get any fire out of that. Something strange is going on...