NO BOOST

[Marajin]

Saw a truck a while back that went from making 36-38 boost to 30 refused to go higher. Turbo had 640k miles. Checked everything tested the cac all kinds of everrything. wasn't turbo. wasn't cac or leak. wasnt anything anyone could find. insite was showin nothing. Upped the turbo tables and wouldn't go any higher.

what u guys post here sounds all to familiar.

After digging deep in ecm I found the fuel was being capped off at a lower than normal level seemed for no reason. truck used to run fine, why it change?

Turned out to be to the fuel system that was throwing no codes whatsoever even though all derates disabled on that truck. Theres fuel derate manager with several reasons that can still activate. Is related to fuel system components like wrong resistance on fueling or metering actuators, shutoff solenoid, cam and crank position loosing sync, and a few other. it can sometimes not bad enough to fault but intermittent or only enough engine dont like. -- They are there to protect engine. Is difficult to find wich one it is cause without the use of c*trm. Insite never showed and said everything was fine.

i think is uncommon but does happen i have seen this.