2006 ISX CM870 High Pyro, surging under load

[sickoftrucks]

2006 ISX CM870 High pyro reading, surging under load. it is a known truck to me, tri-axle dump. KW T800. It was brought to me with high pyro reading, and black smoke, low boost. 1100-1200F. we found the turbo unison ring stuck and broken in the turbo. Replaced the turbo, it runs great, has boost, but still high pyro, 1000-1100f. and it surges under load and boost fluctuates with the surge, it is cutting fuel back. turbo and egr test good in insite, took out the egr valve to inspect, it looks ok. it feels to me like it is overfueling, and the ecm is cutting the boost to protect the engine. also, no codes, we have insite pro. Help