Turbo on its last legs? (VAG TFSI K03 question)

[JB21]

I'm experiencing a weird boosting issue with the Skoda. It started a few months ago with an intermittent issue when on the odd occasion I wouldn't get full boost at WOT. It went away but then came back a few months later but this time I wouldn't get full boost if going WOT over 3k RPM, under 3k it was fine. Now I can only get full boost if I dip my clutch and blip the revs a few times past 5k RPM then if going WOT under 3k RPM I'd get full boost for a few blasts then its gone again, no ELM.

Ive checked the diverter valve, PCV system and all the pipework for boost leaks and all seems fine. Cant bloody log actual v requested boost via VCDS as I've forgot my password on my laptop but it feels like something is defo sticking, waste gate actuator maybe? Turbo is the original and is on 131k miles so its done a good job as its been mapped for 40k miles of that.

So question, can I check/move the actuator by hand on with the K03 to see if its sticking? Or is there a way to check the range of movement of the wastegate actuator in VCDS?

Anything else it could be that can be checked manually by hand?

 

[Rojer]

You could take the vacuum line off and use a hand pump or something to build some pressure and see if it moves. IIRC you should be able to move it by hand but may have to remove the vacuum line to prevent damage to it. As the actuator is cheap is probably wise to replace that first.

Not sure on the VCDS side of things as never really used it.

 

[Andropidis]

Another thing to check is the N75 valve. It can throw a fault code without triggering the EML, if you can get the car scanned. Not sure how else to confirm it's working correctly?

 

[JB21]

Another thing to check is the N75 valve. It can throw a fault code without triggering the EML, if you can get the car scanned. Not sure how else to confirm it's working correctly?

Working now trying to figure out how to unlock my laptop.

 

[JB21]

Managed to log specified v actual boost v boost pressure (waste gate duty N75). You can see in green (from 2k RPM) a good pull, bit of a delay hitting actual but gets there and pulls hard. In red (from 3k rpm) never hits the actual and the N75 readings are lower at the beginning of the pull. I also think 2300mbar (33 PSI) is way to high for a K03 stage 1 remap?

Anyone make anything of this?

 

[Rojer]

Can you send the info to the tuner?

 

[JB21]

Can you send the info to the tuner?

Don't think Shark Performance are around anymore.

 

[vroomtshh]

VCDS boost readings are total, so its 33psi less 14.7 (atmos pressure)

 

[Adey.]

VCDS boost readings are total, so its 33psi less 14.7 (atmos pressure)

was about to type the same thing

 

[JB21]

VCDS boost readings are total, so its 33psi less 14.7 (atmos pressure)

Did remember this for my MPS tuning days, something like 1013mbar. Car is running 18psi which is bang on for a stage 1 map.