cummins isx new turbo and thrownig code

Fire that mechanic. You need that sensor for your engine has to monitor EGTs to prevent piston melt. Cummins sees that and kiss warranty goodbye. You don't want that with a new turbo. That sensor helps control fuel flow. If EGTs are too high, fuel flow drops some to lower combustion heat. Yes the sensor is pricey, almost $150, but it's really important.

 

He is talking about pyrometer probe - it is not connected to the engine, ISX has its own Exhaust Pressure Sensor located on the thermostat housing. It's probably Volvo truck and dashboard computers are throwing those codes. Still, pyrometer readings used to be the most important info for a real trucker

 

The thing about PYROMETER is that if you drive your own truck for longer time (like few years or so) and you learn to pay attention to that gauge over time - you will notice if the readings go higher or lower then they used to be. It will indicate problems with air/fuel ratio. On ISX it might be first indication of VGT Turbo going bad or EGR malfunctions, sometimes even before Check-Engine light comes on. Problem with the Volvo dashboard is that the gauge is very small, but still, this gauge is the most important diagnosing device if you care about your motor. The reason why your mechanic and your trucker friends don't see it that way is because times are changing and even truck owners don't pay attention to their equipment like they they used to - which is also why the gauge don't even exist on most cheap trucks, it becomes an optional add-on, even on new Peterbilts.

I would recommend you buy aftermarket pyro and learn how to use it - Teltek makes nice one

 

I agree with the previous poster. Fire the mechanic. He is wrong about the pyro , and wrong about unplugging the EGR. If you're going to run without the EGR , you should have an EGR delete done. $$$$$
in the meantime , unplug it correctly. Wait until engine is cold , turn the key to ON , but don't start the engine. Walk around to the EGR , and unplug. You're now good to go.

 

Do you have a single exhaust , with the stock muffler ? That noise you're hearing could be the restrictive sound of too much gas , trying to get out of too small an exhaust system.
I know I've heard some of those single stack jobs , under load , and yea , they sound terrible.