boost problem

[martyno]

hi people im new to the audi game and have a bit of a problem! i have tried searching but cant seem to find anything.
i have an a3 '99 1.8t quattro and when i put my foot down it doesnt seem to respond that well all the time. sometimes it is fine but others it just seems like im hitting a brick wall and i have hardly any boost then it suddenly kicks in. any ideas folks? be GREATLY appreciated. cheers, martyn

[20vtel]

my guess would be the n75 valve which controls boost. they are around £60 from audi dealers. check that all boost hoses to an from the n75 valve are not leaking first. the n75 valve is located just after the mass air flow sensor on the turbo intake pipe. it has a 2 pin plug.

good luck.

[robetere]

I had that problem with mine.

The ECU cuts power to protect the turbo when it detects to much airflow.

Short term if you half accelerate through the 3K - 3.5K rev range the car shouldn't jerk about.

Long term:

If you do a VagCom you will probably get the fault code.

00544 - Maximum Boost Pressure Exceeded
35-10 - - - Intermittent


Then it should be as the above guy said: either N75 Valve, Mass Air Flow Sensor, Or a leaking/broken pipe.

In my case it was the pipe.

If you do a resistance check across the 2 pins of the valve you should get 25 - 30 ohms

The attached picture item 4 shows the location of the N75 valve under the bonnet.

[martyno]

Thanks for the info people, great help!

[AwesomeSarah]

Hi
I would say boost hoses too
Do a full check of the hoses
Another one would be the DV , as they are not very strong either
A full VAG COM check would be in order too
Sarah