Can anyone help with this problem my Son has with his Octavia,  he drove to Devon the other week and when going up telegraph hill lost power and went into limp mode.   But later every thing seemed ok turbo cutting in etc,  came back home a few days later no problem.  Our garage checked it and cleaned the vanes etc, then everything was ok.      He's gone to Devon again now for a week,  guess what the same thing has happened again.  Any ideas what may be causing this to happen on long journeys?

Heat acusing the vacuum pipes to collapse possibly combined with a very minor vacuum leak downstream of the collapse resulting in the turbo actuator releasing.

 

It will only happen on a long journey under sustained load, a hot day, large hill, towing a trailer will all contribute to making it happen, simply cycling the ignition even on the hill will often re-esatblish the vacuum but it may drop out again.

 

The pipe or pipes will be degraded in the areas of closest proximity to the exhaust and turbo.

Edited 15 July, 20196 yr by J.R.

How did the garage clean the vanes? Putting in a fuel additive turbo vane cleaner may not be enough as a one shot.

Try moving the vane operating rod to check for lack of smooth movement.

The garage used some system called:   Pioneer Hy-Carbon Engine Cleaning Technology!  That's all I know as its my son's car,  I think what J. R. has suggested might be the problem as the symptoms are the same as my son described to me.  But I still welcome any thoughts on this subject.

Googling the HyCarbon thing, looks like they inject Hydrogen into the fuel system so it combusts and forms water, which steam cleans the internals. Not sure how effective that would be on the turbo, but I'd wager it would be better than "in tank" turbo cleaners.

 

Definitely worth seeing how much travel the actuator has to see if the vanes are seized though. What engine is it? There's always the Mr Muscle technique, which usually gets pretty good results at least for the time being.

I didn't have one then but have bought a Mytyvac now so that I can test the actuator, lines and operating valves if I get similar problems in the future.

 

the way your son can be sure is if the boost comes back if he cycles the ignition and falls away again if the hill is long enough, it may be a case of loading the car up, finding a really long hill and attacking it several times with the engine really hot, in my case it would be towing a heavy trailer up a long autoroute incline in summer.

As J.R. said/implied, what you need is a high torque situation. On my Mk1, it would go into limp mode by accelerating hard in third gear to join a fast dual carriageway where there was a short on-ramp to join. Equally, trying to go up a steep hill in fourth would do the same.

 

The Skoda garage confirmed the diagnosis using a hand held vacuum/pressure pump to attempt to move the vane actuator rod over the full range.

 

So the garage has said that the actuator is at fault on my sons car,  does that mean he has to have a new turbo?