Engine not building boost in6thgear

[Micsol]

So on the highway my truck will do this thing where it won't spool the turbo up in sixth gear it will immediately shift to 5th and then it will spool up fine. Other times it seems to spool up just fine in sixth. Truck is a 2016 with 6.7 and 68rfe. Anyone else have this happen to them and what would cause it

 

[Hoefler]

You don't mention your gear ratio or what rpm your running. If your rpm is below 1700-1800, it will down shift because you are lugging the engine. very common with a 3.42 gear. These engines are happiest running 2000-2100 rpm.

 

[kthaxton]

Sounds like you have the "lazy turbo". While there is no solution I've heard of yet, see this thread.
https://www.turbodieselregister.com/threads/259045-Lazy-Boost

 

[Micsol]

Sounds like you have the "lazy turbo". While there is no solution I've heard of yet, see this thread.
https://www.turbodieselregister.com/threads/259045-Lazy-Boost

Ya this sounds like exactly what I'm experiencing

 

[SnoKing]

Ya this sounds like exactly what I'm experiencing

I only have the issue when over 6K altitude when towing in 5th at 60 MPH, when I sped up to 62 the issue did not occur. I first saw this last fall going South, so after exchanges with kthaxton last winter, in the spring I played around with this again in the middle of Nevada on 93 when coming home. Once I got to lower elevation the problem did not occur.

So it appears to be speed/RPM and altitude related.

You are in Colorado, so you most likely see in quite a bit. SnoKing

 

[kthaxton]

Mine doesn't appear to be related to altitude....but I never/rarely drive any lower than 4000 ft. Whatever the cause (at least on mine) it is very random....as I've mentioned, I drive mine to work daily, some days it does it, some days it doesn't. Sometimes it may only happen once on this particular grade, some times it happens multiple times. It is almost non-existent in the winter, but doesn't come back immediately when summer hits.
Lately, I also noticed a pulsation feeling, but it is very subtle, perhaps because I am paying so much attention to it. I THINK this pulsation happens only when my turbo is being lazy. The numerical boost gauge will not show pulsating boost (i.e. the number stays the same) but that bar graph boost gauge will show slight pulsing. Again, very subtle and may not even be related.

 

[Micsol]

Mine doesn't appear to be related to altitude....but I never/rarely drive any lower than 4000 ft. Whatever the cause (at least on mine) it is very random....as I've mentioned, I drive mine to work daily, some days it does it, some days it doesn't. Sometimes it may only happen once on this particular grade, some times it happens multiple times. It is almost non-existent in the winter, but doesn't come back immediately when summer hits.
Lately, I also noticed a pulsation feeling, but it is very subtle, perhaps because I am paying so much attention to it. I THINK this pulsation happens only when my turbo is being lazy. The numerical boost gauge will not show pulsating boost (i.e. the number stays the same) but that bar graph boost gauge will show slight pulsing. Again, very subtle and may not even be related.

Ya I just got back from a trip to the east coast. And it started doing it around Iowa/Indiana. And I can't remember where on the way back. And just the other day i took it on a 2 hour trip it ran fine all the way there but started doing it on the way back about 30 miles from home.