Just put a 4 inch afe turbo back straight pipe on my 2008 6.7 2500. I have a dpf-r module kit on it also. The problem im having is. When I first start it there is no check engine light. Then when I drive it about 15-20 miles later the check engine light will come on and the fuel economy will go way down. Also when I stop you can hear the turbo almost sound like it is spooling up like a jet taking off. When the turbo is making that noise at idle there is clouds of smoke coming out of the tail pipe. Does anybody know what is going on or have any ideas what it could possibly be.

 

Codes might help to find the problem. IF the EGR is still functioning, then that is likely the cause. The DPF is the filter that hides all the soot that the EGR makes in the engine.

 

I would get rid of that "system" and do some basic EGR/DPF deletes and use a good and proven programmer like Smarty or H&S to run the motor. Any day you don't have an issue with a system like you have is lucky. I think what you have a is a "band-aide" at best, but it needs to be changed.