A3 2.0TDI Power Loss

[csducks]

Right firstly..

if it goes into limp mode while ya driving just turn ya key off and back on it resets the.. whatever the hell its called... you dont have to stop. its been a few months now and its not done mine no more damage.. however...

on the VCDS test it will come up as error overboost etc etc

after trying to sort this out as for one thing i dont wanna fawk out for a new turbo if its just something which is easily fixed. So i have narrowed it down to a number of things.. if its what i think it is based on 6 months off ground work..

what happens, is the turbo waste gate - sticks in one position. its not actually a wastegate as such. its the rod which controls variable turbo vane geometry. it allows a huge amount of boost upto a certain rpm or speed - and can give no more - as it is fixed in a specific position due to jamming. this then flags a code on your ecu, and sometimes u may have symptoms such as total lack of power due to the ecu shutting down turbo control completly.

the remedy is - a new turbo assembly afraid


thats worst case scenario..

or if you take it to a shop that re maps your motor im told they (mos of em) strip down turbo unit and clean off all the carbon which if none of the coild inside are damaged remedys the problems completely as this is what causes the problem in the first place, costs about 30-50 pounds and takes a qualified mechanic around 1 hour t trwo ohours. what i have found out is DO NOT take it to any garage even an Audi one as you will, as you have already found out to your cost be charged based them checking ya car with cable and not really knowing exactly what the prob is.. majority of the time i get you need a new turbo, but not one of em can tell me why, well thats not good enough for me, im not willing to pay that much when it could be something that with a little bit of knowledge time and effort put in could be something really small.. so this is what else it could be..


this following advice as come from other people who have had the same problems..


i'd also recommend removing the vacuum line from the actuator to the N75 and inspect it.
It gets very warm around that area and the rubber pipe can get damaged.
I remember mine was in a bad way so I replaced it with silicone tube from Forge



The vanes usually sticks causing over boost when your cruising at 70-80mph.
You will not get rid of the problem by spaying wd40 on the actuator the problems lies inside.
If you suspect you have a fault with your turbo use vag com go to engine and then into basic settings and select channel 11,
this will work the actuator and it should travel about 25-30 mm and return back to the bottom smoothly.
When there is a problem it will stick or not move the full distance.
You can see the actuator arm if you remove the engine cover.
I have actually got a turbo to work again by doing this and using forte fuel flush but this is rare.

N75 may need replacing

Over boost is normally caused by a clogged N75 valve or sticking vanes in the turbo.


This is what i have found out over the past few months, i could have just wrote the above in 4 or 5 lines but thought you would appreciate an full explanation as it seems thats something allot of garages fail to understand.

if you find out more about this, especially how to remedy please do post as it seems like a common problem and the more we know about what seems such a common problem with Audi motors the easier it will be for anyone else reading this. regards

[v11kal]

Update:

After taking my car back to Audi for the 2nd time they then decided to run diagnostics against the car, which all passed!!!

I took a visit to the flagship dealer and after a number of phone calls - Audi ave me a replacement car ad replaced the turbo unit and only charged me £150 as a contribution fee.

Drive to London from Birmingham last night "first long drive since replacement" everything seems fine, power distribution seems a lot better than it was when it was working!!

So without being any expert, i would say if anyone encounter this problem, its a new turbo job.

Thanks
KH

[leedspaul]

Hi Guys.

After reading all your threads and your problems, it seems you are all experiencing the common Audi over boost problem. (my problem as well). Together you have all come to the conclusion that it is the turbo. (£1200ish at dealers).

To cut a long story story short guys, you don't have to spend anything like that kind on money. I got myne done at Turbo Clinic UK. for a couple of 100 quid, and its run perfect ever since. I hope this thread will be of some use to you guys.

[csducks]

oh right, what was wrong with it then, what did they replace, and how much did it cost you? what car do you drive?

cheers

[leedspaul]

They told me they replaced the stuck variable vain system and then reset it up.

[stu1267]

Hi All, I have an Audi A3 8v 2.0 tdi, I have power loss, it dips in power at different speeds, I have the engine light come on and the glow plug light flash, I turn the car of and then on and engine light is still on but glow plug light is off. would it be dirt in the Turbo or worth replacing the ECU? thanks in advance, do let me know