Where is the overflow valve located? I have been having the same starting problem for quite some time now. I got to do some investigating tonight and could not find the overflow valve anywhere. I am in search of this because the starting problem didn't start until after I had the injector pump replaced. And I think the mechanic might have forgotten to reinstall the spring and ball.

 

On the 24 valve it is next to the fuel inlet on the VP44 injection pump, is modularized and not servicable. A pressure test will tell you in a minute if you are getting fuel to the injection pump.

I would look to the injectors as the problem immediately after pump replacement, unless the mechanic had the filters or heater open for service.

If your flexible fuel hoses are in good condition, and the fuel filter and heater components tight and not leaking a bit, the symptom sounds like contamination got in the pressure line to one or more injectors.