I have the typical loss of turbo syndrome and have been through it before and it turned out to be a faulty MAF sensor which was making the turbo work sometimes and not other,but a quick purchase off Ebay £35 solved the problem.

Now 2 years later I have no turbo at all the car runs ok but lacks power and slows down to 50 up hills and there is no turbo boost.I have changed all vacuum pipes with no joy,the vacuum pipe(I think it should be a vacuum)to the turbo vane actuator had broken off and was replaced,no change.

I bought a replacement N75 valve that operates the vane actuator(wastegate?)and the similar N18 valve that operates the AGR valve etc.No change.I have been under the car for some 3 hours today trying different things.

I have bought a Mityvac vacuum tester,I have attached it to the turbo actuator that operates the rod that moves the vanes inside the turbo,on applying the vacuum the rod does not move at all the only way I can get it to move is by using a long dent fixing tool much like a long screwdriver(2ft)the funny thing is the movement is making the rod move out of the actuator body and on release it goes back into the actuator body(I suppose there is a return spring inside)I find it funny because I would have thought the vacuum would "suck" the rod into the body then return it outwards when the vacuum was lost?All the videos on youtube for actuator testing show the rod being drawn into the body of the actuator under vacuum(using a hand vacuum pump like mine)

Am I going bonkers?I have tried to remove the actuator with no luck today.Any Help advice?Has the actuator failed?

Does the actuator hold vacuum? If not the diaphragm might be broken. If so the actuator will need replacing.

Does the actuator hold vacuum? If not the diaphragm might be broken. If so the actuator will need replacing.

Yes the actuator does hold the vacuum(but doesn't move and the vanes/arm are not stuck as I can move the arm)it is obviously broken or is it?In my original posting I have put I can move it with a long tool but the arm moves out of the body of the actuator and back(under spring tension?)But all the actuaters I have seen move the arm into the body?The vacuum connection is on the right of the actator body which sugest it sucks the arm into the body of the actuator?See my conundrum.

The actual driving description sounds more like a failed MAF to me (or less likely the CTS).

However if you are not getting full smooth movement on the turbo then a vacuum is applied then that points to sticky vanes, is the movement smooth for the latter part of the travel of the actuator control rod?

Edited 10 June, 201115 yr by mbames

(double post)

Edited 10 June, 201115 yr by mbames

Do you get a fault code if you scan the car?

I have applied my mityvac hand held vacuum pump directly to the actuator while I was under the car and full vacum there is no movement of the actuator.I have taken both bolts out of the actuator and swung it down and the rod moves freely operating the vanes so no sticky vanes.I have replaced the MAF and N75 and N18.It looks as thought the actuator internally has broken as applying vacuum directly does nowt.While the actuator is attached I can move the arm with a long tool and there is resistance from the actuator(the spring inside)but the arm does move.What I am asking is should the arm move out of the actuator body when a vacuum is applied(I would think the vacuum draws the arm into the actuator body)so has the diapram or whatever inside the actuator body collapsed/broken?Basically the actuator is not working whan a vacuum tester is attached.

No fault codes.I did have one before I swapped N75 valve.Car runs like a car with no turbo.

I have applied my mityvac hand held vacuum pump directly to the actuator while I was under the car and full vacum there is no movement of the actuator.I have taken both bolts out of the actuator and swung it down and the rod moves freely operating the vanes so no sticky vanes.I have replaced the MAF and N75 and N18.It looks as thought the actuator internally has broken as applying vacuum directly does nowt.While the actuator is attached I can move the arm with a long tool and there is resistance from the actuator(the spring inside)but the arm does move.What I am asking is should the arm move out of the actuator body when a vacuum is applied(I would think the vacuum draws the arm into the actuator body)so has the diapram or whatever inside the actuator body collapsed/broken?Basically the actuator is not working whan a vacuum tester is attached.

If the vacuum actuator is not moving the rod against the spring when vacuum is applied, then it is faulty.

The actuator is not available as a separate part from Skoda. I suggest you post in the items wanted forum. Someone may have a broken turbo with a working actuator.

You didn't specify the year/engine so can't be any more specific

If the vacuum actuator is not moving the rod against the spring when vacuum is applied, then it is faulty.

The actuator is not available as a separate part from Skoda. I suggest you post in the items wanted forum. Someone may have a broken turbo with a working actuator.

You didn't specify the year/engine so can't be any more specific

Ok I have a 1999 T Reg 1.9Tdi Octavia AGR engine has anyone got a working actuator for sale?

I would still like to know which way the arm is meant to move out of the actuator body or into it?Thanks Simon

In this case, the rod is pulled towards the actuator as vacuum is increased.

You can find vacuum actuators that push, pull, rotate or pivot.

Very interesting, so why does mine only move outwards using a tool has internal spring collapsed with the diaphram ?I will look to purchase another as car performance is great as long as I avoid hills!

So if my actuator is broken it has pulled the rod fully into it's body what does the turbo do?Not work?over boost and shut off?Are the vanes at full angle to spin the turbo at its fastest or the opposite?This is what I need to know to calm my mind.Thanks Simon

So if my actuator is broken it has pulled the rod fully into it's body what does the turbo do?Not work?over boost and shut off?Are the vanes at full angle to spin the turbo at its fastest or the opposite?This is what I need to know to calm my mind.Thanks Simon

Check out some of this guy's videos:

http://www.myturbodiesel.com/1000q/multi/limp-mode-TDI-fix.htm

Without seeing the position of the lever on the turbo, I can't say what it's doing.

Take a look at http://www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/body_vnt15-turbo.html

Ok I have seen a similar one before,I still don't know which way the actuator arm should move under vacuum(out of its body or be drawn into its body)?

see post #12

The rod should move into the actuator under vacuum and the spring should push it out when vacuum is released.

Ok the saga continues.I have removed the turbo wastegate actuator with reasonable ease after the second attempt.I have attached my vacuum tester and the arm won't move,So I attached the pressure/blowing(the opposite of vacuum)side of my tester and the rod moves outwards up to 6mm and when I release the pressure it moves back in!So the actuator appears to work,the connection to the turbo vanes moves easily( I have been running on veg oil for over 80,000 miles and have used cleaning additives regularly so it should be nice and clean and not sticky vanes)

I have to find out now what is meant to apply pressure to the actuator to make it move out,maybe the pipes are connected wrongly from the N75 valve?

Ok the saga continues.I have removed the turbo wastegate actuator with reasonable ease after the second attempt.I have attached my vacuum tester and the arm won't move,So I attached the pressure/blowing(the opposite of vacuum)side of my tester and the rod moves outwards up to 6mm and when I release the pressure it moves back in!So the actuator appears to work,the connection to the turbo vanes moves easily( I have been running on veg oil for over 80,000 miles and have used cleaning additives regularly so it should be nice and clean and not sticky vanes)

I have to find out now what is meant to apply pressure to the actuator to make it move out,maybe the pipes are connected wrongly from the N75 valve?

The actuator operates on vacuum not pressure.

Checked all pipes and they are all correct.I have run the engine and pulled off the pipe from the N75 that provides the pressure to the wastegate actuator and there is a "litte"bit off air being pumped out,you can just feel it if you put your tongue against the pipe end,it doesn't feel strong enough to move the actuator as it is quite difficult to do it by hand.I know the engine is not running on load so maybe the pressure builds up?I am going to test that the system pressurizes and there are no leaks(I have seen it done on Youtube)other than that I am stuck,is there any way I can tell if the turbo vanes are actually working/spinning?The car still runs ok but no boost,I don't know if the turbo is doing anything?There are no fault codes on vag com.I have just down loaded the lite software to see if that does anything but can't affor $99 dollars to register.Any further information would be good,I live in Birmingham and may have to take to a turbo speccialist or can somone recommend a mobile mechanic?

Checked all pipes and they are all correct.I have run the engine and pulled off the pipe from the N75 that provides the pressure to the wastegate actuator and there is a "litte"bit off air being pumped out,you can just feel it if you put your tongue against the pipe end,it doesn't feel strong enough to move the actuator as it is quite difficult to do it by hand.I know the engine is not running on load so maybe the pressure builds up?I am going to test that the system pressurizes and there are no leaks(I have seen it done on Youtube)other than that I am stuck,is there any way I can tell if the turbo vanes are actually working/spinning?The car still runs ok but no boost,I don't know if the turbo is doing anything?There are no fault codes on vag com.I have just down loaded the lite software to see if that does anything but can't affor $99 dollars to register.Any further information would be good,I live in Birmingham and may have to take to a turbo speccialist or can somone recommend a mobile mechanic?

The N75 is a changeover valve. If it were just an open/close valve, once vacuum was applied to the actuator it would never move back.

In the off position, the N75 connects the actuator to the air filter. The vacuum is 'lost' so the spring moves the rod back out.

In the on position, the N75 connects the actuator to vacuum. This pulls the rod in.

The N75 duty cycle determines the boost.

If you apply vacuum to the actuator with your Mityvac and it doesn't pull the rod in, then the actuator is not working.

Ok so my actuator is broken as it does nothing when a vacuum is applied to it via my myty vac hand vacuum tester it on responds to a positive pressure from my myty vac(it can provide a vacuum(suck)or pressure(blow) ie if I were to attach a bicycle pump to it and pumped away the actuator arm would move out of the body,from your reply my actuator arm should move into its body when a vacuum is applied.Is it possible to explain why my actuator is working the opposite way(apply positive pressure not a vacuum and the arm moves outwards,remove positive pressure slowly and arm moves back in?I am also sure I should get some boost even if the actuator is not working?Thanks for any help Simon

...Is it possible to explain why my actuator is working the opposite way(apply positive pressure not a vacuum and the arm moves outwards...

The rod is attached to a diaphragm in the actuator. Whilst it is designed to be pulled by vacuum, there is nothing to stop it moving the other way under pressure.

I take it you are testing the actuator with a piece of tube that came with the MityVac. If not try it, to eliminate the vacuum pipe from the N75 (it could be collapsing under vacuum).