Hey y'all new to the forum and also the newest owner of a 2015 6.7 Cummins!!

I figured I'd come here for some help I've done a bit of researching but can't seem to pinpoint

When taking off after being stopped I have a bad hesitation. It will start to accel for about a second and then bog right down almost as if the pedal is inactive and then blow a decent puff of coal. The whole ordeal before it starts to accelerate again is about 2-3 seconds. I've looked up dead pedal but the part that is throwing me off is the puff... Is this fuel/air related? I've checked on screen readings when bogging and everything seems to check out. More annoying than anything. The truck has full emmisions.

Thanks guys

 

Do you have a CEL ? How many miles since the fuel filters were replaced? Answer these questions and we can precede with diagnostics.

 

No CEL and fuel filters are done on time every time

 

Your truck acts as if the vanes in the turbo are getting stuck in the open position but that should instantly throw a code and CEL. You might try doing what some have done to get the shutters moving freer, which is warming the engine up completely, and then while on a stretch of open road where running 50mph won't impede traffic, manually put the truck in 4th gear with the exhaust brake in the full on position and do a hard acceleration and then immediately let off the throttle and let the truck slow back down. Repeat this about 5 or 6 times and then put the truck in standard drive mode and stop the truck and drive away under normal acceleration and see if it still bogs. It is hard to diagnose this since no CEL and trouble codes to even point in the right direction. If you do this "hot supper" approach to freeing the turbo up let me know if it helped at all or whether it is no better. Your turbo could also be suffering effects from the turbo actuator not working correctly, but I don't think you should start throwing expensive parts at it without some idea what is really causing this.

 

Great! Thanks for the informative post I will try this tomorrow and get back to you!
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Did you ever figure out what’s wrong with it

 

​​​​​​Yessir. Faulty FCA causing drops and huge spikes in the rail. Explaining the bogging and then immediate smoke.

Found out after I hooked up my scanner and watched specified rail pressure vs actual rail pressure

 

I had an issue like that on my FORD F-250 6.7 & it was the lift pump slowly 🐌 but surely it started giving out, I replaced it with an airdog, but I should've just replaced it with the factory lift pump

 

I might be double posting here, not sure what happened to my previous post.

It ended up being the FCA. It was causing drops and spikes in the rail which explains the bog and smoke. Found this by watching live data from my scanner
Funny thing is, I swapped the new one in everything was perfect until around 6 months later I had idle rpm surge. Knowing I had just replaced the FCA I was confident it couldn't have been that. Did some testing and swapped my OLD one back in, it's been solid for over 30,000km now. Very strange. Now I have two just incase. Very easy part to swap.

I've since deleted and tuned and the truck is running better than it ever has!

 

well you came out cheap cause the Fuel Control Actuator isn't that expensive. I figured it was fuel ⛽️ related