Mystery - 240 Engine Died

Ok I have reread your posts. It loses injector pulse and sprak while cranking!? Hmmm. What are you using to read injector pulse? Curious.

I would look at the crank sensor waveform and make sure it's not doing anything odd. Or you could have a short circuit from whatver hackwork was done during an engine swap.

ZVOLV, it does not lose injector pulse and spark while cranking. It loses it as soon as the engine fires up/starts. There is something definitely odd going on here.

Likely start checking the wiring harness for a failed wire that is grounded somehow.

Problem solved - purely mechanical. FOD (foreign object debris/damage) got inside the bell housing of the transmission and bent a portion of the plate that the rpm sensor uses to determine engine speed. The plate was just far enough away from the sensor in the bent section that it lost the signal and reported no rpm which would cause the ECU to shut-down until you turned the key off and turned it back on. Bent it back to being straight as possible and the engine now runs fine. With all the parts I replaced, the engine should run fine for quite some time.

Just curious: when you pulled codes early on, what was shown as a fault, if anything?

Glad you got it! Lucky guess on my part to suggest crank sensor waveform analysis. It would have shown up!

Mr. V, there were no codes. Here is a picture of what the ring looked like before it was straightened.