3406 b performance

Check boost corrector line from manifold to injection pump. It it is bad engine runs like with no turbo.

Boost corrector is a small diafragm inside injection pump to limit rack movement if no enought boost pressure (to avoid too reach mixture and black smoke).

 

Yes it is the fuel ratio valve it runs from intake to top back of pump. Before you throw money at it have a tune up done on it by a sure nuff real cat man. There are so many little things that could cause this it ain't funny. I can tell you 1000 post turbo is a lot higher than I like to see one for sure. Mine is the opposite of stock but 750 post turbo is bout where she stays. If the guy is worth his sand on a Cat he will find the problem with a tune up. It could be anything from timing off which is my first thought to governor weight trouble. Be sure to do a bridge adjustment too

 

I'm guessing timing is off. The engine would not make 28psi if the diaphragm was leaking. For turbo I would switch to a modern BW replacement, a 177148 will work extremely well.

 

The timing spec is scribed on the end of the pump cam.

 

Definitely look at the advance, first . The 4mg advances that weren't completely updated, would disassemble themselves, and flyweight dowel pins going through your front gear train, ain't pretty.