Just purchased 94 Audi 80 TDI Avant

[Dermo123]

Hello Folks,

Just purchased 94 Audi 80 1.9TDI Avant with 133,000 miles on the clock.
A couple of issues need resolving and the main one is the power. It drives like a standard non turbo diesel, i.e. is is a bit flat across the entire rev range.
So taking a look at the engine I noticed a pipe (about 0.5 inch diameter) from the top of the turbo body cut off and blocked up with a screw. I could not see where this pipe was supposed to go so I went looking on the web for a picture of this engine and found the one attached. The arrows show the pipe that is missing from my engine. Can anyone tell me if I need this pipe and is it the cause of the poor performance I have?

Other issues are ABS light stays on intermittantly, the wipers won't work on intermittant setting and stop in middle of window if you use the flick wipe function. Sunroof will not operate (Electric).

I guess the lack of power is what I would really like solved. Any ideas?

[micheal balbrig]

Hello Folks,

Just purchased 94 Audi 80 1.9TDI Avant with 133,000 miles on the clock.
A couple of issues need resolving and the main one is the power. It drives like a standard non turbo diesel, i.e. is is a bit flat across the entire rev range.
So taking a look at the engine I noticed a pipe (about 0.5 inch diameter) from the top of the turbo body cut off and blocked up with a screw. I could not see where this pipe was supposed to go so I went looking on the web for a picture of this engine and found the one attached. The arrows show the pipe that is missing from my engine. Can anyone tell me if I need this pipe and is it the cause of the poor performance I have?

Other issues are ABS light stays on intermittantly, the wipers won't work on intermittant setting and stop in middle of window if you use the flick wipe function. Sunroof will not operate (Electric).

I guess the lack of power is what I would really like solved. Any ideas?

Is your fuel pump the same as the one in your picture?
The 1z engine appears to have a different pump and the pipe you describe
can have its end blanked off.
Check for any splits in the turbo short rubber hose,normally underneath

[Dermo123]

Is your fuel pump the same as the one in your picture?
The 1z engine appears to have a different pump and the pipe you describe
can have its end blanked off.
Check for any splits in the turbo short rubber hose,normally underneath

You are correct, when I took the engine cover off I saw that it was a different fuel pump to the one in the picture so that is probably not it.
I will have to go routing underneath at the pipes I guess!

[Dermo123]

Had a good look around the pipes in the turbo area and all pipes, hoses clips looked and felt intact. Took out the air filter and housing to get more room to access. There was a good bit of dirt and grit in the intercooler intake under the headlight. Cleaned this out and reconnected everything.
Car still drove the same. I then unplugged the MAF and there was even less power. Struggled to climb a hill. It improves a bit when I plug it back in.
Does that eliminate the MAF as a possible cause? I can't find any other electrical connection or pipe that is faulty/misplaced other than the one I mentioned in my first post. Any further ideas?

[fourringsrus]

Fuel filter and lines being semi blocked can pi-- you about like this, not an expensive thing in order to illiminate ,seeing as you have just bought it

[micheal balbrig]

Had a good look around the pipes in the turbo area and all pipes, hoses clips looked and felt intact. Took out the air filter and housing to get more room to access. There was a good bit of dirt and grit in the intercooler intake under the headlight. Cleaned this out and reconnected everything.
Car still drove the same. I then unplugged the MAF and there was even less power. Struggled to climb a hill. It improves a bit when I plug it back in.
Does that eliminate the MAF as a possible cause? I can't find any other electrical connection or pipe that is faulty/misplaced other than the one I mentioned in my first post. Any further ideas?

The most likely hose to be split is the very short one that connects to the
inlet , only about 3 inches long, and possible to miss. remove and check the underneath of hose, if split it should be oily.
If your car has manual window winders the problem with the sun roof may be the large relay over your knee with panel removed.
If you dont find the cause of lack of power, it may be best to have fault code read as a faulty 3rd injector can cause problems, as indeed many other items.
Other things to check=Turbo lever can move freely with circlip taken out.
Next thing worth doing although a days work is removing complete inlet manifold and cleaning all carbon deposits and all oil from pipes and n 75 valve. Label all hoses before removal and if possible compare with a similar model beforehand in case they are incorrect at present

[Dermo123]

The most likely hose to be split is the very short one that connects to the
inlet , only about 3 inches long, and possible to miss. remove and check the underneath of hose, if split it should be oily.
If your car has manual window winders the problem with the sun roof may be the large relay over your knee with panel removed.
If you dont find the cause of lack of power, it may be best to have fault code read as a faulty 3rd injector can cause problems, as indeed many other items.
Other things to check=Turbo lever can move freely with circlip taken out.
Next thing worth doing although a days work is removing complete inlet manifold and cleaning all carbon deposits and all oil from pipes and n 75 valve. Label all hoses before removal and if possible compare with a similar model beforehand in case they are incorrect at present

Thanks for your help Michael, it may be a week before a get a chance to go at it again but I will let you know how I get on.

[Tobster]

The picture you posted looks like an 'MTDI' conversion; that is, fitting a suitable (or suitably modified) mechanical-type injector pump and accelerator cable, making the ECU, and all electrical sensors, completely redundant.

Just had similar done to mine (though waiting for another pump to be built because something's not right with this one, will report the results as and when...)

[Dermo123]

Finally got back to this and a local Audi specialist told me that my changeover valve needs replacing. It has a 1993 date code so more than likely it was never changed before. It has a part number 028 906 283 B. My local dealer can supply one but he says the B is an F. I assume it is the same? Can anyone tell me what the changeover valve does?
It is a small part bolted to the inner wing on the drivers side with 3 pipes going into it and one 2 pin electrical connection.

[micheal balbrig]

Finally got back to this and a local Audi specialist told me that my changeover valve needs replacing. It has a 1993 date code so more than likely it was never changed before. It has a part number 028 906 283 B. My local dealer can supply one but he says the B is an F. I assume it is the same? Can anyone tell me what the changeover valve does?
It is a small part bolted to the inner wing on the drivers side with 3 pipes going into it and one 2 pin electrical connection.

Sorry I cant tell what it does as mine never gave trouble.
I think from what you describe, that your model may be a 93
As far as I know the unit on the 94 model is attached to the air box.
Also on the 93 model there is a mini plastic pipe that goes from the intercooler (behind bumper to
Any 93 models I had have the fuel pipe on the top centre of the actuator.
The 94 model has pipe at rear end of it. Regards Michael.