Sudden Low Boost

[dunc12]

Hi all,

I'm having what seems like a low boost issue and am looking for some insight. Until recently, my 1.6TD would easily boost to about 12psi at very low RPMs and stay there until I let off.

Now, seemingly overnight, I can only achieve a maximum indicated 6psi or so. Boost will now only come on after a large delay, and will rarely reach even 6psi. I'm also getting more smoke at the top end, helping confirm that boost is much lower than it was.

I tested the BOV by plugging it and going for a drive, to no effect. I also removed the intake boot and checked the shaft for play or excess oil. I also checked my intercooler piping for security (it's all tight and secure) I suppose my next step is to test the wastegate. I can achieve this by plugging the upper deck pressure line leading to the actuator, yes?

Looking for some advice. Cheers.

[RabbitJockey]

What turbo? K14 or k24 gave very sticky wastegates

[golfmk1tdr]

Well I have similar problem driving me nuts right now, but you should look if all of your intake/exhaust manifold bolts are tight.
On my car exhaust manifold wasn't straight and 2 bolts came loose it was blowing exaust gas out BEFORE turbo. 
But I had that fixed and it was working now I have whe same trouble again I hope I haven't lost nuts because I put new stuff on.
Also if you can try blocking turbo at filter/intake side and blow some air into intake manifold.
If your wastegate is working it should open at certain pressure but hold pressure otherwise.
My car doesn't hold pressure on intake manifold I don't know if it should so please check if your is the same...

Hope we can both solve our issues, remember to post if you solve it!   

What turbo? K14 or k24 gave very sticky wastegates

How do you check for sticking wastegate? 
Is opening the turbo only way?

[air-cooled or diesel]

Also if you can try blocking turbo at filter/intake side and blow some air into intake manifold.

you dont want to do this,, for 1 thing you can easily collapse intake,

[golfmk1tdr]

Also if you can try blocking turbo at filter/intake side and blow some air into intake manifold.

you dont want to do this,, for 1 thing you can easily collapse intake,

BOV should release presure before it becomes dangerous,
even with blocked BOV I belive intake should take 1.5 bar easy.
Why should it colapse it's made to hold pressure is it not?
Did you see intake colapse like that?
Sorry to question you I don't really know just using logic if you have experience please help out.

[dunc12]

What turbo? K14 or k24 gave very sticky wastegates

Thanks for the replies. The car has a stock turbo, to the best of my knowledge. This would the KKK K24, yes? I have noted the "KKK" triangle cast into the housings. I'll check for loose/missing exhaust hardware as soon as the torrential downpour stops.

[RabbitJockey]

Wastegate is probably just stuck

[air-cooled or diesel]

BOV should release presure before it becomes dangerous,
even with blocked BOV I belive intake should take 1.5 bar easy.
Why should it colapse it's made to hold pressure is it not?
Did you see intake colapse like that?
Sorry to question you I don't really know just using logic if you have experience please help out.

1 thing there you say should. another if you block off wont pressure continue to build and push anything out/ on the opposite end you may find your air filter collapsed and go down the intake, along with your block *off there. the intake is made to hold a constant pressure Flow, no restrictions, there was more,
-&, i assume by bov you mean a blow-out-valve, 1 thing its main application is safety, protect intake,* * but still if theres a hitch, your going to have a mess. like 1 hitch is it wont release enough pressure for blocking pressure side for too long.
-edit, you better check and see if you even have a bov.