Never had a fancy Snap-On scanner, just the little Actron scanner, and all it really does is send the signal to a bulb that flashes. The actron is powered by a 9v battery, and doesn't depend on the diagnostic port for power or ground, other than to read the code.
There's an old thread around here somewhere on how to use jumpers to send the signal to the check engine light, in order to count the flashes and retrieve the codes.
In any case, it's kinda crazy that you've done all this thinking and talking without pulling a screw & push-plug and pulling out the passenger kick panel. With it removed, you'd know immediately if there's a piggyback chip sticking out of the J3 port. Given that you've talked about dead pins, I don't see how you haven't already been in there. To answer an earlier question, the stock EEC-IVs do not take a tune via a flash. The J3 piggyback chip carry any adjustments to the tune, and when removed, the EEC reverts back to its stock tune. This can be useful for diagnosis, so long as you have an MAF 'calibrated' to your injectors. You should really run through Jrichker's cranks but no start checklist. Failing to crank when hot can be your TFI module, a faulty fuel pump, a failing MSD box, and several other things.
The fuel smell is pretty typical of cars with a 'calibrated' MAF, because the MAF can't change injection duty cycle while cranking. In fact, what size injectors are you running? 24s and 30s shouldn't cause a failure to crank, but the bigger the injector, the harder the car will be to crank. I don't really suspect this is your problem since flooring the throttle & cranking should clear the fuel out. However, with what you've said to this point, I wouldn't be surprised if you have several factors contributing to the problem you're experiencing.
