[Dave at Pelican Parts]

When you disconnect the head temp sensor, the FI thinks the engine is colder than the south pole and will command pretty much as much fuel as can be delivered into the engine. It is a very rare circumstance that allows the engine to run with that much fuel going into it...

BTW, "seized" implies that some parts of the engine welded themselves together and the engine will no longer rotate without "heroic" measures. If you cannot even turn the engine over at all with the starter, you have "hydro-locked" it. That's where there is so much liquid in the combustion chamber that there isn't even room for the piston, so when you try to make the piston rise it gets stopped by the non-compressible fluid. You can remove the spark plugs and see if the engine turns over at that point--keep your face away from the engine bay and keep an extinguisher on hand, because you can get nice little fountains of gasoline coming out if that is indeed what is going on. (Don't ask how I know that.)

--DD