Sticky actuator?

[GazzaA3]

Afternoon all, so issue I have at the moment is boosting.
It will boost ok then when let off/change gear it struggles to build boost back up!

Recently had it smoke test which I replaced a few pipes etc, and diagnostic read which didn't show anything.

Also, a friend had a few hours on my car, he discovered the actuator was nearly hard to compress I think he said, used some wd40 and seemed fine, well until now!
This was done about 3 weeks ago.

So could I think maybe the spring is worn?


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[Solberg]

Unplug the vacuum hose to the actuator on the turbo. Then drive safely, wastegate will now be permanent closed so you will run max boost, probably 1,8bar(26psi) ++ so be careful.

However if the wastegate actuator is "sticking" it wil not boost, if you take off the vacuum hose and see only say 0,3bar boost its faulty. On the other side if your turbo does a spool from hell assoon as it boost (1,8bar(26psi) ++) your wastegate is not faulty. Be very careful with this, if you are on stock rods you could end up braking your engine, just unplug vacuum and try give it a little boost just enough to get a feel if the wastegate is opening or not (yes you will notice).

You could also use an air compressor and put air into the actuator nipple and see if the wastegate arm is moving.


If the turbo holds boost this way I would move on to the N75 valve.

 

[GazzaA3]

Right, I will give that a go soon! And will report back what it does!


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[GazzaA3]

So iv just taken it out for a quick spin.
Unplugged the hose connecting onto the actuator and it boosts better.
I didn't go full throttle, only up to 20psi ish


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[Solberg]

which means its prolly not sticking.

i put my money on faulty n75 valve then. Uf you know someone with a 1.8T you could try theirs to double check.

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[GazzaA3]

which means its prolly not sticking.

i put my money on faulty n75 valve then. Uf you know someone with a 1.8T you could try theirs to double check.

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I have spare N75's off of my old A3 but I guess there be wrong?


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[Solberg]

I have spare N75's off of my old A3 but I guess there be wrong?


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Same thing just try it and see if its boosting right.

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[GazzaA3]

Will give it a go


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[GazzaA3]

Afternoon, so yesterday I tried a different n75 sensor with the same effect as before.

Will boost fine instantly but if let off/change gear boost is either nothing or very slow to increase with rev range


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[GazzaA3]

Right, so I un bolted the rod onto the waste gate.
Un hooked it and the arm was hard to move the butterfly. That's the best way I can explain it.
A blast of gt85 and was freed up, put back together and it seemed to of solved this issue.
I know the gt85 won't last long cause of the temps.
So what he failed here or what can I put on to lube it up.
The picture shows what part of the turbo I mean.


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[GazzaA3]

From a old turbo


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[Stuart B]

I think moly grease takes a lot of heat (its designed for CV joints) - I didn't know you were supposed to lube the outside of this part.

 

[GazzaA3]

Afternoon all, so after some time I need some guidance.

I unbolted the arm and 'wiggled' it back and forth with gt85 and seems better. All back together is fine, until I put it under a lot of load.
It will drive fine boost fine for days until I do that, even with applying 10 sometimes 15psi of boost for short period it would still be fine.

Any guidance on this would be helpful


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[wr6warren]

Sorry for the thread revival, but did you ever get to the bottom of this? I have a TFSI octavia with identical issues.

cheers!