2016 mp8 Boost pressure

[daniel179]

I drive a 2016 Mack Granite heavy haul with an mp8. What might cause the boost pressure to go to 36 psi for a short period and then drop to 28-29 psi with a noticeable loss in power? I can hear the turbo spool up when the boost goes up and the turbo slow down when I loose boost pressure? And what should the correct boost pressure go up to ? And I also have codes that I can't find anywhere online. 

[Onyx610]

33psi 

[Onyx610]

Two things come to mind. Sticking turbo actuator/nozzle ring. Or possible EGR valve issue. 

[daniel179]

Would any of those cause the check engine light to stay on with a code ? 

[daniel179]

                       ENGINE 

SA 16 ENGINE MODULE 

DTC P052712

                       VECU

MID 144

PSID 40

FMI 4 

                    ACM

SA 17 ACM MODULE 

DTC P206C00

These are the codes i can pull up from the dash, only one of them pops up when the lightning bolt comes on along with the fan. I don't remember which code pops up with the lightning bolt and fan so I just put all 3 codes.

[Onyx610]

Ones a fan speed sensor code. Ones a daytime running light code, and the other is a DEF quality sensor code I believe. 

[Onyx610]

The issues I mentioned earlier won’t always give a CEL. Do you have anymore info on the issue? Was anything done to the truck before this started? Anything done to try and fix this issue? What kind of transmission? Deleted? etc. 

[Joey Mack]

In addition to Onyx's post's..  do you have a boost leak where the turbo pipe and/or the C.A.C. pipes mate up?  there are o-rings there that can leak..  Good luck, Onyx is pretty smart about the MP's..  jojo

[daniel179]

Nothing has been done to the truck as far as a delete or anything else. It has a mack 18 speed manual. It is a company truck and I can't seem to get the shop manager to do anything to remedy any of the issues with it so I try to figure out what is wrong with it and then either try to fix it myself or go to someone I know that will get it taken care of . Nothing was done to the truck previously before the issues, everything seems to just happen on its own. 

10 hours ago, Onyx610 said:

The issues I mentioned earlier won’t always give a CEL. Do you have anymore info on the issue? Was anything done to the truck before this started? Anything done to try and fix this issue? What kind of transmission? Deleted? etc. 

 

[Onyx610]

Start with checking for charge air leaks like Joey said. There are a few checks you will be able to do, but without Premium Tech Tool your more then likely at a loss.