> I have 20-50 Castrol in the engine and it is...
> Cranking voltage is about 10V when cold.

I'll bet these two have teamed up.  The system needs pretty close to 10v
at the fuel pump and ECU to run, and while cranking you've probably
pulled this down too far.  Easy to check by measuring the voltage at the
fuel pump while cranking it, or by trying to start it with jumper cables
from a running car.

My .02

malcolm