C15 not getting boost

Have you tried plugging the waste gate?
You can use a small screw,like the side screw on a cb.
Need to pull the piping and inspect the turbo.

 

Most times my dad was having boost issues on his single turbo c15 it was the turbo/wastegate. They seemed to have a thing for turbos and broken rocker arms.

 

If plugging the waste gate makes a difference,check that line all the way around the motor for a hole or kink.
Is this a mbn motor?

 

Skip the bolt in Wastegate.

It's easier to take a pair of needlenose vice grips and clamp the rubber line hard, it'll pinch it off for the test...

 

just kink the hose and wrap a ziptie around it. did you take the intake hose and exhaust pipe off and inspect the turbo blades? before you pinch off the wastegate hose make sure the wastegate isn't stuck open.

 

is the engine stuttering or sound like it is running out of fuel? if so it maybe on fuel side. filters, plugged hoses, bad check valve, plugged tank vents.