CM870

[Big_Rig_99]

Hi All, Just want to say thanks in advance for anybody that can help me.

I have a CM870 that has been de-mandated and is running a fixed non vgt turbo.

The issue I am having is that the truck de-rates itself on long hills when it gets hot (Boast stays constant but feels like fuel is being cut). Its a 565 but has a signature 600 turbo on it. It makes good power and the boast gets up to about 34-35. No check engine light comes on and the oil and coolant temp are in line.

Any Ideas?

Quick Update; Using Insite. Looking at the User Fueling State: The sequence that comes up in "Altitude Derate"