Boost Issues

[K Simmonds]

Bit of a long shot but perhaps the N75 is playing up in some way, can you try another without having to buy a new one?

[K Simmonds]

Also check the pipe from the N75 too the wastegate,. another thing, did you disturbe the N75 whilst fitting your RS2 air-box? If so is it fited the right way round?

I have a good spare N75 you could borrow for postage costs.

[S2central.net]

This week I was working on a car with a failed N75... it was leaking internally so that air was bleeding from compressor port to BOTH other ports. That and another air leak made it run kinda ugly. It was a potentially dangerous fault too as the WG wouldnt open properly, but limiters in the ECU stopped it from self destruction.

Good way to test it is with ECU in output test mode when it is turning N75 on & off... while blowing air into the compressor port of WGFV - you can verify that the air path switches between the other two ports in response to on/off signal. Of course this is just a low speed test of N75 - it doesnt verify that it can follow the higher speed duty cycle (on/off) during normal operation.

[Le S2 Audi]

Also check the pipe from the N75 too the wastegate,. another thing, did you disturbe the N75 whilst fitting your RS2 air-box? If so is it fited the right way round?

I have a good spare N75 you could borrow for postage costs.

Thanks for the offer - I may take you up on that...

Where is it and what does the N75 look like... So I can check it out 1st...

[Jas11n]

Thanks for the offer - I may take you up on that...

Where is it and what does the N75 look like... So I can check it out 1st...

Three way solenoid valve located down behind drivers headlamp Ken.

[AndyP]

HTH

[andyg plym]

i know you said you can get boost for 1 second,but have you thought about knock sensors?

ive had this happen tome before

[Le S2 Audi]

i know you said you can get boost for 1 second,but have you thought about knock sensors?

ive had this happen tome before

Wouldn't that show on Vag Com thoo??

[dobbin]

when was the last time you changed the fuel filter, because you did run it out of fuel
and thats never a good thing , see the recent thread on fuel pump delivery and try this
test . your car now needs more fuel than it did when std

[Le S2 Audi]

when was the last time you changed the fuel filter, because you did run it out of fuel
and thats never a good thing , see the recent thread on fuel pump delivery and try this
test . your car now needs more fuel than it did when std

Not sure if Matt changed it yesterday... Will have to ask him..

Would this affect the boost??

[Le S2 Audi]

HTH

Thanks Kit & Andy..

Will check that as it's just where the air box fits and maybe I knocked it..

[prj]

They have never been touched car was/is stock other than Homfries & RS2 MAF & Box..

How does that relate to the fact that the diaphragm maybe torn?
You don't have to touch anything for it to tear.

Unbolt the cap and check the diaphragm, if it's torn, you will get overboost.

[Le S2 Audi]

How does that relate to the fact that the diaphragm maybe torn?
You don't have to touch anything for it to tear.

Unbolt the cap and check the diaphragm, if it's torn, you will get overboost.

I have no idea - as I'm not a mechanic - but thanks for the tip...

Are these units not pressurised in some way??

Does it damage them by opening it up???

[prj]

No!
Nothing will happen
Just carefull unbolt the screws around the wastegate cap, then hold the cap down, else it might pop off, make sure not to drop anything, the spring has stoppers on the top and bottom.
The diaphragm is the thing separating the upper and lower chamber.

Get your car tested for boost leaks as well, or rather vacuum leaks - pressure test from the MAF...