Cummins ISM not reading boost correctly?

[Mikesuburban1]

(02-24-2017 )in2trux Wrote:  Scan gauge boost is electronically calculated, not actual.
Did you replace delta P (pressure differential sensor?)? The one with 2 tubes on the intake manifold.
Those tubes are notorious for clogging on the Isx and Ism. You can't clean the sensor, only replace.
It's a key sensor and can throw ecm function. Does it cough or sneeze? I don't know how else to describe it,
thats what it sounds like, very quick interruption in power. Some call it turbo cough.
I had that problem with the Ism I use to run, egr tune up cured it.
I put new exhaust back pressure sensor and made no difference. Removed one end of the cooler and exhaust flows good. Took the diff tubes off and cleaned them they really werent that dirty. Removed delta p sensor and it wasnt clogged or anything but there was moisture in it is that normal? I have a buddy coming over tomorrow with his insite is there anything i should be looking for with the sensors?
While your at it, exhuast gas pressure sensor should be replaced too.
They're about $80-90.
Other than that I would check for leaks in CAC that my be showing at high boost.