Audi 80 TDI Loss Of Power.

[jacksticks]

Hi all.

Our audi 80 tdi used to have a great boost in power when accelerating - presume it was the turbo. This seems to have gone and i am finding myself with my foot flat on the floor in second into third gear to get any power - the turbo seems to have vanished. We have also noticed the car when idling will suddenly jump up in revs - from 1000 to 2000 rpm then back again. This could be something to do with it? Almost like a vacuum leak that suddenly throws more air into the engine. Any help, as always greatly appreciated!

[micheal balbrig]

Check the short rubber hose close to the turbo, there may be a split in the underside of it.

[jacksticks]

OK, will do.

[frielp]

Brake Pedal switch

[jacksticks]

Will check the hose tomorrow - I may take a photo as not entirely sure where it is!

[jacksticks]

Is this something I could diagnose? Thanks

[micheal balbrig]

The short black rubber hose is approx 3 inches long, 1and a half inch diameter. It is on top of engine and connects to an aluminium type flange at turbo.
Sometimes it develops a slit underneath which you cannot see. It is the first thing to check before moving on.

[jacksticks]

Ok great, thanks.

[jacksticks]

Sorry this has taken me so long to reply, I have been working away etc. The hose is ok so I can rule that out. What I have found is the problem (intermittent revving on its own and lack of turbo boost ) only occurs when the car is up to temp. I have been doing some research and some people have mentioned the boost pressure control valve, or the charge pressure valve? Could these be the problem and are they easy to test/change? My other worry is that engine timing/cam belt have been mentioned in google searches, but surely I would know if the timing was out?

Thanks in advance.

[micheal balbrig]

First, no point in worrying about timing etc,as it can be checked,probably manually first and then I think it can be fine tuned with vcds,on a graph. You could not know if it was incorrect by a small amount.
Also have a full scan done with vcds it may help find a reason for lack of power,and the best option at present
Keep a look out where you may locate spares in case you may need items like what you mention or maybe the number three injector.
Also talk to a diesel specialist about rev. issue. Diesel Bobs name often appeared in posts.

Some further items to check are all the mini vacuum hoses, they can become soft and not do their job. They can also fill with oil,as can some of the valves,certainly the one forward of turbo.
There is also a very small one near brake m/c servo.

Engine is sure to have high miles and may benefit from a good clean out of inlet manifold area

[jacksticks]

Right, thanks. Will check those hoses. Engine done 173,000, not even worn in! How would I check the engine codes etc? Is there anyone in Stockport/Manchester area that could do that?

[micheal balbrig]

Hopefully someone that reads your post may volunteer to help you.
The vcds needs a two pin adapter to suit the 80 tdi.
The adapter fits a two pin connectot in your fuse box,side nearest o/s wing
On another note , there is a small bore mini plastic pipe coming from the intercooler,which is hidden behind the front o/s wing,check that is not damaged at this point and along its circuit