FLD120 12.7 LOW POWER

White smoke usually indicates water getting into the combustion chamber, check head gaskets maybe?

 

How much boost at the turbo?

 

white smoke possible boost sensor issue i know old detroits loose a lot of power from boost sensor

 

First off I'd check fuel pressure under load.
If that checks out put a sight glass in the return line and check for air.

Could be compression getting into the fuel rail.

White smoke doesn't always mean a head gasket or water issue. Fuel injected at the wrong time will cause white smoke also.

 

I would not discount that air cooler leak causing the problem. One time my hose was loose on the air cooler & that was the problem when climbing hills.