CM870 High Pyro/Low Boost intermittent under load

[tree98]

Copied from the thread I linked Rawze said this.......

There are a few reasons for this derate.

Most of the time on the CM870's as a result of someone disabling the EGR in some way and not re-programming it (or not programming it properly) for such things. In this case, the EGT's are usually higher then normal. It sounds like yours are lower than normal.

It can also happen if the ECM fails one of the fueling, metering, or fuel shutoff solenoids. Usually, you get an intermittent/occasional code for one of these components this in the fault history, but on rare occasion, you only get the derate without the code. This can cause lower then normal EGT's as well, as the injection timing could be off.

Could also be a malfunctioning turbo controller. They are air operated on the cm870.