WTF?! Boost Problem Help

[93jdmlaser]

I finished the car up today and took it out. Well we take it out and runs good. Have 17psi. Come back empty the shit from the trunk and went to take it out got 10psi give or take a pound. Well ok we try tunring up the mbc alot still the same. Take out the mbc and run the line thats tapped at the bov to the wastegate still the same. Then we took the line off the wastegate so it should stay closed and its still the same. Since I have an internally gated vtrim that has the adjustable actuator we thought maybe it was blowing open so we adjusted that and still got the same. We couldnt find any major leaks but Im guessing something has to be lossing boost real bad. I have no idea why its only at 10 now.

 

[ddavisaf]

There are only a few reasons why this might happen.
1) You have a boost leak.
2) Your wastegate arm is not fully closing. This may be due to a crack in the turbine housing, or a bad wastegate.
3) Your turbo has enough shaft play to hit the housing and limit the amount of boost it can produce.

You should first run a boost leak test. You want to hold 20 psi for a minimum of 30 seconds. Anything less than that is unacceptable.

If your boost leak test is good and the problem persists, check for shaft play by pulling off the intake pipe. Move the bearing up and down/side to side and see if it hits the housing. Then pull it in and out. There should be no in and out play and little side to side play.

If nothing is wrong, pop off the turbo and check for signs of cracks or splits in the turbine housing.