ISX15 CM2250SN surging whilst at speed/load

[Aj1189]

Hi,

Have been coming across a slight issue with the Australian ISX15 CM2250SN euro5 engine. Drivers are making complaints of a surging whilst travelling at speed and under load. Seems to be prevalent with the DS10001 & DS10003 cal files (600hp/2050ftlb-600hp/1850ftlb). May happen with other cals & hp ratings but due to size of loads quite uncommon to see other ratings so can’t comment if it does or not. Also does not seem to be calibration revision specific either.
Doesn’t seem to be OEM specific with the issue and has come up in both Kenworths & Weatern stars. Vehicles in question all run road train config pulling 3 x twin deck livestock crates, empty weights between 55-70 ton (150000-155000lb) and gross weight when loaded between 120-140 ton (265000-305000lb). No complaints of surging whilst empty only when loaded and travelling at speeds between 90-100km/h. Has been recorded on video monitoring the Murphy gauge & road relays that boost pressure & hp used drop for a split second then come back in like a silent derate is activating but no codes or faults present. Does not seem to be any uniform pattern when the surging happens and can come in any time/temps/road conditions.

Wastegates have been checked and happens at different levels of wastegate settings from 210kpa-220kpa-240kpa-260kpa. Fuel systems have been checked and verified rails holding pressure, no leaking of injectors, pass throughs, rail relief valve.

Wondering if anyone else has come across this before or if anyone might know where to look in calterm to prevent this happening.. Have got a video of it happening and have got a couple insite images & Xcal saved from vehicles where this is happening..