loosing boost at 3500 revs

[alex 80]

hi after somepointers on where i should be looking to fix my fault
i have a pd150 05plate leon thats cover 40k with full vag history and completely stock

when stretching its legs in 3rd or higher gears as soon as it hits 3500revs it loose all turbo boost and the turbo will not work untill the car has been switched off and on again (i assume it resets something)

anyone point me in the right direction to solve this problem??

 

[Muttley]

Sounds like limp mode, which is usually due to sticky turbo vanes in these cars, although not at such low mileage. Is it mostly driven on short journeys or at low speeds?

One other possibilty is a stuck EGR valve.

First step is to get the fault log read, at a dealer (not cheap) or with VCDS (post in the VAG-com section to see if anyone can help)

 

[alex 80]

had it on vag com other week fault reads
charger pressure positive devation can't remeber the fault code though.
the car before i brought spent its life on the isle man so yer short low speed trips all the time

 

[BenG]

Sounds like overboost triggering limp home mode (no boost), which is consistent with sticking turbo variable vanes.

Might be a good idea to try a turbo clean (e.g: the Innotec kit) to see if you can free off the vanes. http://innotecturboclean.co.uk/

 

[Muttley]

All points to limp mode due to the turbo vanes sticking on carbon deposits.

One way that some have used with success is described as the "italian tune-up" - more accurately, get the turbo hot enough to start burning the carbon off. The process assumes that your car is otherwise in good condition, oil and water levels are good and the fluids and filters have been changed in line with the service requirements.

You need a section of dual carriageway, preferably uphill, where you can drive at 70mph in third gear so that the engine is at high revs. A few minutes of this will get the turbo properly heated up (not overheated, but towards the high end of its range) which will encourage the carbon build-up to either burn or flake off. Some have reported seeing sparks in the mirror as bits of carbon leave the exhaust pipe.

Obviously don't overdo it, and once complete carry on driving normally for at least another 5-10 minutes to let the turbo cool again.

 

[sssstew]

yep agreed with muttley. either try clearing it yourself as per above, or you will need to drop the turbo off and clean it up.