6nz 475 turbo question

Tried the search feature to no avail, so I will ask here. Friend has a 2001 Pete 379 with a 6nz 475 Cat. He just had the motor rebuilt in the last 5,000 miles, replaced the turbo. He says that the turbo will not make more than 20 lbs of boost, no matter what gear, loaded or empty, foot to the floor, only 20 lbs. I suggested pressure testing the air to air, checking the clamps, etc. I was wondering if there is anything in the ecm or any sensor that might cause this to happen. Any suggestions?


Thanks


Shogun

 

He bought the truck from a bank repo, had barely driven it before he found a pitted liner, so he doesn't know what boost it should make. ECM has not been reprogrammed, and like you said, his friend has a motor just like it making around 27 lbs of boost on a stock turbo.

 

2001, so far it has been getting 6.0 mpg pulling a hopper bottom grossed out at around 68 mph, but it falls flat on any hills. He says he is going to take it to the shop Monday, I was just curious if the computer could be the culprit since it is the same every gear and every different variable applied.