could be the return valve not workin properly its the bolt next to the inlet

 

What does the return valve do?

 

Allows the fuel to return to the tank,if it leaks it will let a air bubble get in there.

 

May I snag this thread, I tried finding one on cold start issues. I've a 2003 Dodge 2500 Diesel - and up until this year, have NEVER had any starting issues. Have checked - starter, battery, battery cables, fuel pump, injectors, heater (starting heater??) and some small fuel heater????, and alternator - none of which test with problems. BUT it still will not start in cold weather. Cold being here in Colorado now, below 40 degrees Fahrenheit. Above 40 to 50 it is stiff, but below will not start and all it does is grind.

I may have misnamed some of what's been checked, but believe me have tested everything possible and all with a negative issue.

 

You may want to post this in the 3rd gen section, but it sounds it may be your intake heater going out. Good luck and welcome to DieselBombers

 

Thank you, my mechanic believes he's found the problem finally - I've got to take it in and have it recalibrated; apparently there is a Technical Bulletin dealing with this problem and he just found it. So we'll see.