For what it's worth, it turned out not to be an ECM failure. I discovered (in the pouring rain) that the small screw that holds the rotor on the distributor shaft had fallen out. Screwed it back in, started right up. I think this may be part of why I couldn't get the timing right, too.

Thanks anyway!

88 Trooper, 2.6 5spd
89 Trooper RS
92 Montero