Truck Repair: F250 7.3l POWERSTROKE, injector nozzles, return valve

Question
QUESTION: 1995 model F250 7.3l powerstroke engine
After the truck has been shut off for a period of time (2 or more hrs.), it will start fine and run good for about 2 miles, then dies, with some effort it restarts and runs good for about another mile and dies again.  After two or three restarts it runs good for the rest of the day.  this happens everyday and is getting progressively harder to restart.  I have changed oil, Rotella 15w40 and filter.  I have changed the fuel filter,  fuel hoses. New copper gasket on the input to the fuel pump.  It seems to me that air is getting into the fuel system but I can't figure out where.  or is it possible the the fuel pump, or the injector fuel pump can cause this?

ANSWER: Hard starting can occcur through the following
1. Air in the fuel system
2. Faulty fuel return valve, stuck open or malfunction
3. Faulty injector nozzles
4. Worn out injection pump elements.
If the hard starting is accompanied with black exhaust smoke, then the air filter may be blocked or some problems with the turbocharger.
Ensure to re bleed the system of air and leave to run idle for about 5 minutes, then you can run normally.
You may also need to check that your fuel tank is not contaminated with dirt and or check the quality of diesel fuel.

Regards.

---------- FOLLOW-UP ----------

QUESTION: the truck does not start hard to begin with, only after it dies.  after the second or third time it dies, it runs and starts great for the rest of the day or until it has sat not running for a while.  Then it will start o.k. but dies again after about 2 miles

Answer
When you shutdown an engine, fuel stops going to the injectors. However, most diesel system are designed to keep fuel in the high presure lines to assist in quick starting when next you need to do so. This fuel is prevented from draining out of the system through the action of the non-return valve fitted on the return line. If the valve malfunctions, then you may experience hardstarting. Also any opening that allows air in to the line by vacuum is a contributor.

So please purge your system of air, check the valve, then if problem persists have your fuel injection pump overhauled.

Regards,