VNT turbo actuator movement - loose then stiff

[Galaxy130]

sorry another question....TDI 130 55 plate having put on a new MAP sensor a week ago, everything has been running better than before though still not 100%. Yesterday I was driving quite hard in 3rd and the car went into limp mode for the first time ever (had the car 6 mths). Switching off and then on again either doesnt clear it or it clears it but limp mode comes back very quickly with normal driving. I'm awaiting codes to be read (I cant make my ebay VCDS lite work anymore!) . Meanwhile have been under the car to look at actuator arm etc. When I first pulled down on the arm it went down really really easily and smoothly and I worked it up and down with ease. I came back 30 mins later the arm is just about solid and I can hardly move it. All the pipes were connected both times. Is there a simple explanation for this difference or does it give a  clue as to what is wrong?!

thanks

[Galaxy130]

strewth has anyone ever got the circlip out of the actuator arm in order to see if the turbo arm moves freely without pulling half the engine to bits??!! I've now given up having spent the last 2 hrs trying to remove a single bolt that holds on the actuator bracket to the turbo......

[Chrispb]

It's fiddly but can be done as I've done it.

[Galaxy130]

did you do it by leaving the actuator body in place as you can only see the clip area with a mirror from beneath the car. I intended to undo the 2 bolts holding the actuator then somehow swing it to expose the clip but one bolt seized solid and now its rounding over - thinking of perservering with a ring spanner that will undo rounded bolts now. Cant get anything other than a ring spanner on it

got fault code P1556 charge pressure control negative deviation and am hoping its not sticky vanes......

[Chrispb]

Yes only accessible from below, deffo ring spanner job, the clip I managed with a pair of long nosed pliers.

[Galaxy130]

really good youtube vid here that shows circlip removal not required? just remove 2 bolts securing actuator then work lever by holding actuator body...

https://www.youtube.com/watch?v=o1Hvt2b7PL0

[Galaxy130]

well, if it is of interest, I removed bolts from actuator and was able to move the arm on the turbo with actuator attached and the arm was very obviously very loose and free moving so presume not a case of sticky vanes. Stuck a mityvac on the actuator and it moved to the stop from 3 to 18 setting as it should so no probs there and no vacuum loss. Removed pipe from N75 and attached mityvac to that end and no vacuum loss there at all. Underboost seems to have cured - no more limp mode. I dont really know what I have done to fix this!!! The only thing I can think of is when using a mirror to inspect the actuator rod, there only seemed approx 12mm of shiney metal showing by diaphram   whereas now its just over an inch so maybe I've freed the actuator up without realising.

[Mirez]

Quite probably, the actuator only sticks at one end of the travel and is generally very loose feeling throughout the rest. Good job