Q: Since I bought the 06 f250,from time to time, it would not build any boost. Then it would work great for weeks, then no boost again. It would start boosting again on its own. Now it has 0 boost for over a week. I've changed the MAP, cleaned the turbo vanes, changed the solenoid, checked all pipes,changed oil and fuel filters. Still no boost.the ring in the turbo was stuck badly, I had to use a hammer and chisel to get it off. But once I cleaned everything, and put it back it was moving freely.
A: First thing I would do would be to check if the turbo actuator is working or not. You can do this easily with the truck at idle. If you listen to the exhaust note, it should change as you unplug then plug in the turbo actuator. If it is changing tone, then we can assume the turbo is moving inside. If it doesn't, you may want to recheck the unison ring for proper installation or change the actuator. If all that seems good, the obvious comes to mind also. Check the hose between the intake manifold and the map sensor for tears or breaks. If that hose does not give signal to the computer, the truck will not produce any boost. I would also check the intercooler boots and intercooler itself for leaks.