Hello!
Have a friend that spent a crap ton of money building a Cummins for his Ferd, and he is having severe coal rolling issues, it never cleans up even when he backs the star wheel off.
He is also having exhaust temp issues. I told him it just sounds like he doesn't have enough air for the amount of fuel, but he has a nice turbo.
Below is his parts list, if you have any ideas please let me know!
Thanks, Mark

1998 12v with the 215 pump.

1. Crank turned and polished

2. Bored .30 over

3. Stage 1 cam

4. New stock head with heavy valve springs

5. 150hp injectors

6. 4K governor spring

7. .025 delivery valves

8. Fleece cheetah 63mm turbo

9. AFC live

10. Timing set at 18 degrees

11. Fass fuel from a ford 6.0 (65 psi) with 1/2” fuel line from fass pump to p-pump

12. DPS exhaust manifold

13. 5” exhaust with 4” down pipe

14. I can’t remember what harmonic balancer it has, but it’s after market and pricey.

 

First question that came to mind after reading this was to ask what kind of air filter is he using and obstructions in the intake system.

 

Agree, check the air intake.
The injectors could be dirty, leaking and/or just dumping to much fuel. Try putting the stock ones back in and see what it does.
I could be wrong but 65psi of fuel seems way overkill.
Sounds like a good build but I'd start with the simple and easy checks first.