All,

I have an older A4 1.9 TDI (R Reg - 1998) which has a recurring but intermittent problem with the turbo.

The turbo seems to cut out on journeys above roughly 10 miles. I do a lot of miles and so, as you can imagine, this is getting quite irritating!

The engine still runs but there is a total lack of power or accelleration when this occurs.
No warning lights appear at all.
If I stop the car and leave it for a about 30 minutes, the turbo kicks in again but will often cut out shortly after.

So far, the Idle speed valve and air flow meters have been replaced without resolving the problem. The engine mapping sensor has also been checked and is working fine.

Have any of you encountered similar problems? If so, what was the resolution?

Due to the mileage 179,000, I am reluctant to spend much more money on the car but this is the only issue with it and if it can be easily solved, it would be worthwhile getting it sorted.

Cheers,
Simon

 

I have no experience with TDI, however, it sounds like the car is in limp mode.

While not throwing a CEL there might be some stored codes in there.

Check the DV, & make sure all the vacuum hoses & boots are tight & sealed.

Any way you can get any data logging of the boost curve?

 

Cheers for that. All of the hoses seem to be tight enough.
It has been into the garage a couple of times and had the funky diagnostic thingy attached to it to check for error codes. None of these have pin-pointed the cause as yet.
It is strange that the turbo works for the first few miles and then cuts out.
I have noticed however that when the turbo is working and I accellerate hard in 2nd or 3rd gear, there is a fair amount of black smoke emitting from the exhaust.
Could it be that the turbo is just coming to the end of it's natural life? If so, how much is that likely to cost?!!

 

not likely the turbo, and as far as i know black smoke usually = running rich doesn't it??

 

It does sound like the car is running into limp mode for some reason and black smoke usually means it's running rich.

 

2k it's a diesel, there is no diverter valve, uneeded, diesels don't have a throttle body which in turn kills the idea of vacuum hoses because it doesn't really make any vacuum without the restriction of a throttle body. Sounds similar to a complainton a jetta tdi I had.Take off the intake boot and make sure the intake manifold is clean and clear. After the years carbon had built up in the manifold and in the egr cooler restricting air flow. As far as power for ten miles, maybe it is going into a limp mode.

 

Thanks for your responses.
A number of you mention limp mode. What is that? How is it triggered and what can be done to prevent it from doing so?

 

hey persins, this site deals mainly with the performance of gasoline audi's. go to tdi club with your problem and you will likely find more knowledge there for you ride! click on this, good luck!
http://www.tdiclub.com

 

Hello,

did you check the EGR (Exhaust Gas Recirculation) valve ?
I have a friend with a TDI engine that complains about that a year ago.
He went to the service and they made him an EGR cleaning (air, sprays, ultrasound cleaning) and the engine is working smoothly now. (replacing the part is an option too)
You may also checkthe sensors from the exaust, air intake and some other that I forgot it, that "tell" to the EGR how much to open/close.
More informations about EGR here

Hope I told you something you didn't knew,

 

Hello!
MAy have your solution, because it seems that you have my problem that I had a year Ago... When there is black smoke, you should control the intercooler Hoses (big ones) that one of those may have holes.

I have an Audi A4, 1.9 Tdi '96 110bhp. I have problem with my Turbo, I cannot hear the turbo "whistle" and when I drive, I have not enough power, It cannot pass the 3000 Rpm. I have read on internet that I should change 1 thin hose from the Exaust to the ECU, I have cleaned this hose and seems Ok, I don't know which may be the problem, because this happend even the past year and I have tested the MAF with computers but it was Ok and I don't know which may be the problem, Please if someone can show me the right steps for solving definitively?

Thankyou all!