The problem I had most commonly in many hundreds of hours under diesel was
air getting into the line. the least bit of air getting into the fuel line
will accumulate till it shuts the engine down, replacing the fuel line might
be worth doing.
From:
Subject: Diesel starting problems
Date: Monday, November 21, 2005 6:56 PM

I'd change the filters, re-prime and retest.

Also it's possible that the injector pump or lift pump has a defective
check valve thats allowing the fuel to drain off and not allow it to be
pumped into the injector pump.