possible problems

[mike 850]

my t5 isn't holding boost properly, i've replaced all the vacuum line from the inlet to the turbo but still doesn't make any difference, i've had a quick look around the boost hoses but cant see any splits.
basically its been 280'd the gauge goes straight to the end without any probs then slowly drops to around 3/4 mark and holds there, still very quick but obviously i want it running right, im new to turbo'd cars but i dont think theres any probs with the turbo itself, no smoke or hesitation or any strange noises, any suggestions would be gratefully recieved
thanks

[Goof]

What speeds & in which gear?
Mine likes to give full boost (indicated) and maintains it in higher gears, haven't really had time to check in lower gears tho!

[spesh]

Could be a weak actuator? what milage is on your car?? high at a guess.

[mike 850]

its at 119k now, it had a new engine fitted by volvo at 75k but im guessing they probably didnt change the turbo, how easy is the actuator to change?
cheers for advice so far

[mike 850]

What speeds & in which gear?
Mine likes to give full boost (indicated) and maintains it in higher gears, haven't really had time to check in lower gears tho!

forgot to answer this one, it seems to do it in everygear or definatly 3rd upwards if your only on full boost for a short time its fine, just when your in that gear through the whole rev range

[craig]

same as mine and it turns out my turbo is on its last legs

[mike 850]

i really hope its not, just went out side armed with my hand pump psi gauge and the actuator arm starts moving at just over 2psi and wouldnt go past 3 so not sure how accurate my gauge is but i think i might have a tweak of the actuator tomorrow see if i can get it up to 4.5ish?

like i said earlier this is my first turbo'd car(so dont know much about them), i cant understand if its a weak actuator why it would reach peak boost quite early then drop off?? i just would of thought it wouldnt hit peak, correct me if im wrong, please