A4 1996 Tdi 110 Turbo Cut Out?

[lscolman]

Hi,

Wonder if anyone is able to help. Bare with me, as it's quite convoluted.

Fault is when I give my A4 1.9TDI some welly in 3rd gear, I get to around 3,300 rpm and the turbo drops. If I leave my foot on the floor, it will sometimes kick back in at 4000rpm, but other times cut out all together. Only an engine restart will bring the turbo back.

I have tried the following:-
Replacing the MAF
Replacing the CAT
Cleaned out the manifold (which was caked)
Cleaned out the ECU to manifold tube (which had oil in it, as did the ECU)

Not sure if this is related, but I use a K&N oiled air filter, and this has been on the car since about 2001. I had read an article in an Audi magazine years ago about K&N filters causing a problem when oils comes away from the filter, but can't recall the details.

A couple of current theories are that the Diesel pump might not be delivered the goods, and also that possibly the oil that has gotten into the ECU has rotted the diaphragm which senses the air flow.

Does anyone with knowledge about ECU's know if a) there is a diaphragm in there, and whether it can be replaced?

Apologies about my lack of technical knowledge, and please please feel free to correct any of my misunderstandings.

When I put he car on fault diagnosis, I get two faults reported, which are not permanent, and can be cleared.

Abs Manifold pressure
Manifold pressure

Each of these faults occurs when the turbo cuts out.

Any ideas would be most welcome!

Cheers, Lee