Audi turbo goes off when driving fast?

SwordofLight

I have a 2.0tdi A3. When I'm driving, the turbo does its job as normal, plenty of poke. Then if I drive it harder than normal, all of a sudden power goes from the pedal, and the turbo doesn't work. The coil/ glow plug light comes on, and it flashes.
If I turn the engine off and on again (while moving, dont try that at home kids) it seems to reset and the turbo works as normal again.
Anyone any ideas?
I'm thinking there is some sort of pressure/ heat sensor that protects the turbo by going into this 'safety mode' ('limp' mode I think).

demanufactured

Ovetboost.
Plug it in to a diagnostics system and run a scan.

SwordofLight

demanufactured wrote: »

Ovetboost.
Plug it in to a diagnostics system and run a scan.

I have the VCDS but nothing showed on the Autoscan?
What causes overboost? Should I change the actuator?

demanufactured

SwordofLight wrote: »

I have the VCDS but nothing showed on the Autoscan?
What causes overboost? Should I change the actuator?

Could be anything.
Could be the wastegate not opening.

rex-x

demanufactured wrote: »

Could be anything.
Could be the wastegate not opening.

No wastegate on these, vnt turbo although could be the vanes sticking

SwordofLight

demanufactured wrote: »

Could be anything.
Could be the wastegate not opening.

A lot of forum posts saying to change the map sensor? Anyway to know if the Wastegate is faulty? Turbo sounds normal when driving so am thinking no vacuum problems or air leaks although white grey smoke on startup from cold.

demanufactured

SwordofLight wrote: »

A lot of forum posts saying to change the map sensor? Anyway to know if the Wastegate is faulty? Turbo sounds normal when driving so am thinking no vacuum problems or air leaks although white grey smoke on startup from cold.

Could be a vacuum leak also.
Get into someone to look at.

Farfromhome02

Like said vanes could be sticking
Google the mister muscle clean on the turbo,goes in the exhaust side of the turbo,I took apart a vnt turbo recently and could see the carbon build up which would restrict the vanes from freely moving

Plenty of videos on YouTube about it
Be careful with that Mr muscle

The Red Ace

Your 2.0tdi audi has all the symptoms I had on my A6 two years ago, I even did the mr.muscle jpb on the turbo it helped for a while but eventually had to replace it as it nearly drove me mad if I had a long journey to do. I had close on 200k miles up before I replaced it and got varying quotes up to 1500euro. I got a rebuilt Garrett turbo from rebuilders in Co. Louth and fitted it myself, it cost 301e delivered and the cars performance is as new since.

SwordofLight

Going to try the Mr muscle treatment tomorrow. Also will clean the maf sensor again. Anyone know if there would be a map sensor somewhere also or is it one or the other.
Red Ace that's interesting did you get any smoke?
Also have a glow plug faulty but afraid to open that in case dirt gets into the hole. It's full of debris and the Hoover doesn't fit.

SwordofLight

No luck I'm afraid. Tried the Mr muscle for 2 hours in it then it drove really well for about 15 or 20 mins trying best to red line it and it was flying. Then just down at pretty normal revs coming onto motorway it just went again. So I reset it and kept driving it hard, thinking maybe carbon deposits take a while to go. But after 6 mins of more hard driving it went into limp mode again. Tried it twice afterwards with the same results. Should I give it another Mr muscle treatment?
Also have a new fault on it now -
MAF - "implausible signal"
And Oxygen (lambda) sensor B1 S1 "signal too high (rich)" intermittent
Any ideas?

9935452

SwordofLight wrote: »

No luck I'm afraid. Tried the Mr muscle for 2 hours in it then it drove really well for about 15 or 20 mins trying best to red line it and it was flying. Then just down at pretty normal revs coming onto motorway it just went again. So I reset it and kept driving it hard, thinking maybe carbon deposits take a while to go. But after 6 mins of more hard driving it went into limp mode again. Tried it twice afterwards with the same results. Should I give it another Mr muscle treatment?
Also have a new fault on it now -
MAF - "implausible signal"
And Oxygen (lambda) sensor B1 S1 "signal too high (rich)" intermittent
Any ideas?

It sounds very similar to what used to happen to the fathers 01 passat.

Driven hard it would go into limp home mode, ie no power when accelerater pressed. stopping and restarting the car would reset the problem.
VWs of that era were well known for MAF problems which was the problem with the fathers car.

Cleaning them rarely worked for long .

Supposedly if you disconnected the MAF it would run normally and that was the way to know if it was the MAF

The Red Ace

When I used the Mr Muscle I left it for 24 hours because if there is hard soot in there it wont do the job in 2 hours, also pull the rod that opens the vanes up and down and feel if it is sticking before you start it up after the cleaning process it will help to remove the carbon

raabbles

People have pretty much said anything I would think of as reason, but I just wanted to ask about the autoscan. Do you have a full paid version of VCDS or just the lite/shareware version? Only reason I ask is because the lite autoscan is very limited and doesnt check any sensors beyond a basic set, so it probably isnt checking what you need and giving you a "false positive" no faults reading.