Turbo - need some help (2.0 TDI)

[Lion Heart]

Hi guys!

Hoping you can help as need a little!!

Having some rough idling issues, especially noticeable when revving between 1,000 and 2,000 RPM's (stationary for testing).

I've had a look at the Turbo, more specifically the actuator that sits on top, and the arm (piston) that pushes downward from underneath.

So I got under the car and got my partner to rev the engine so I could watch what was happening. Basically the actuator arm is locked in the full downward position. Whilst the engine is running I cannot manually push it back up. With the engine off I can push it up manually.

I tried the test where you shoot a bit of air from a compressor into the actuator to see ifthe arm moved, it didn't move at all.

When revving HIGHER 9nearing red line) the arm moves a little bit. You can also see when revving lower that there is pressure where the end of that arm bolts on to the arm to the turbo as you can see the pressure release as the arm relaxes, but the arm does not actually move (unless higher revs and then only a little bit).

What is confusing me is in the YouTube video's I found it seems that the 'normal' state is the actuator arm in the up position, and when activated it pushes down. But mine is locked down if that makes sense.

Is it meant to move up or down on the 2.0 TDI?

And any clues to what might be happening with mine??

 

[Pyeman]

Actuator is a common fault on the PPD140 and 170

 

[Lion Heart]

Yes, I thought it might be. I'm goigto buy a cheap pressure tester kit from eBay (£12) and use it to see if that arm on the actuator will move whenmanual vacuum pressure s applied.

 

[Baka]

Is the car spooling and holding boost as it should when you're actually driving? You probably won't get the waste gate to move with no load on the engine.

 

[Pyeman]

Yes, I thought it might be. I'm goigto buy a cheap pressure tester kit from eBay (£12) and use it to see if that arm on the actuator will move whenmanual vacuum pressure s applied.

You can't, so don't waste your money!!

Its electric and you can only test with VAS, VCDS etc

However if the Actuator was at fault, you would get a fault code for either under or over boost and the engine would go it to limp mode.

Its a fairly easy job to diy.

For rough idle, I would look at the egr valve first. I may be coked up and not shuting correctly.

 

[Lion Heart]

I saw this video online and so thought it should be easy to test?:



Skip to 1:55 in.

The car seems to drive ok, although it's a new car (to us) and so nothing to compare to.

The EGR valve is definitely ok. I've removed that, it was pretty clean to be fair, cleaned it up anyway, tested that it opens and closes using VCDS, and the EGR valve is definitely working ok.

Noted when stationary and engine cold if I raise the revs from 1,000 up to 2,000 instead of being nice and smooth it stutters back and forth itself on the revs kicking in around 1,600 upward. So something definitely not quite right there.