US /vs/ EU ignitor module, HELP PLEASE?

[Red]

I'm a yank with a 6/1985 production GT-S, original owner and yes, I do try to pamper it.

Anyhow...last year the car decided it wouldn't start up on hot summer mornings over 90F (about 34C) and the final solution was autumn, when it got cool again. And, I disassmebled, cleaned, reassembeled the ignitor module wiring and thought maybe that fixed it.

This summer, same problem. After putting 3000 highway miles, at high speed in decent weather, on the car, the summer heat came over 90F every morning again and again, no start, period.

Fuel pump has power (EFI, COR, cold start, AFM bypass, etc.) all the way back. Engine runs like a fine swiss watch when it starts, and restarts without any problem when the engine bay is 200F (90C+) on highway restarts. So it is something most peculiar and since "fiddling" with the ignitor module helped last year, out of desparation I'm thinking of replacing that "throw parts into it" as a last resort.

I've tried to locate a used ignitor module with the same parts numbers (there are may slightly different ones, apparently the dwell and timing are different in each) and there are none to be had. At $700US Toyota no longer offers new parts.

But a 3rd-tier supplier still has "the right part" available, maybe, for $350US and an "EU market only" part for $60US.

So you might see why I'd like to know, how are the EU and US versions of the ignitor, both for the 1985 4AGE GT-S engine, different? Should they be "good enough" with perhaps a slight tweak in the timing or dwell making no real difference except in the emissions? Perhaps the ignition curves are designed for different gasoline octanes? (We don't have gasoline in the US anymore, we have this damned "E10" ethanol blend anyhow.)

Will my ECU get terribly upset and start demanding a translator and exotic dishes?

So if anyone knows the real differences...You'd be doing an original owner a HUGE FAVOR by clueing me in. I usually don't settle for less than OEM perfect but in this case, I'll be happy if the damned thing will just fire up and go back to running again!

Red