AAN engine problem???

[Orion]

The car used to run fine, then the induction kit came loose and after that every time I put my foot down as soon as the turbo really starts to kick in the power just goes and starts kangarooing.
I've changed the MAF and it hasn't fixed the problem
Now the error codes have changed to Maximum boost pressure exceeded and engine speed sensor faults. I understand there are 2 of these and they're about a 100 quid each and I'm not even sure thats the problem...
Any ideas?? cos i'm going

[HMS-S6]

The car used to run fine, then the induction kit came loose and after that every time I put my foot down as soon as the turbo really starts to kick in the power just goes and starts kangarooing.
I've changed the MAF and it hasn't fixed the problem
Now the error codes have changed to Maximum boost pressure exceeded and engine speed sensor faults. I understand there are 2 of these and they're about a 100 quid each and I'm not even sure thats the problem...
Any ideas?? cos i'm going

The speed signal fault always comes up when the engine is not running at the time of the scan mate

[HMS-S6]

Sure you've not knocked a hose off the N75 valve etc??

[Orion]

N75 valve?? Sorry to sound daft but I'm a VW lad. This is my first proper audi and I'm a bit clueless...

[Orion]

But pretty sure there's no hoses off, unless its on the bottom of the intercooler, cos I can't see it without taking that huge panel off the bottom

[HMS-S6]

N75 valve?? Sorry to sound daft but I'm a VW lad. This is my first proper audi and I'm a bit clueless...

No problem dude, everyone's learning!!!

Its a little 3 way valve just bellow and to the side of the induction hose, also check for splits in that big concertina hose to the turbo.

http://forums.quattroworld.com/s4s6/msgs/22625.phtml

Showen on here - brilliant site

Rich

[S2central.net]

If it has blown hoses off... that will cause air leak - resulting in excessive boost pressure fault - bet you have fuel cutoff at 4000rpm. The ECU stores this fault until it is cleared by diagnostics or you simply pull the 'motor' fuses for a minute. Then the ECU starts off with a clean sheet.

If you still have an air leak then the fault and 4000rpm cutout will return.

[Orion]

Yeah fuel cut off sounds right and yeah 4k sounds about right, but I've cleared the codes a few times. So u reckon it's gotta be a boost leak?

[HMS-S6]

Yeah fuel cut off sounds right and yeah 4k sounds about right, but I've cleared the codes a few times. So u reckon it's gotta be a boost leak?

That is usually what causes this yeh, or i think (maybe wrong) if one of those little hoses comes off the n75 can cause that too. Just thought of it since thats where you've been working - but yeh usually a boost leak

[S2central.net]

Yeah fuel cut off sounds right and yeah 4k sounds about right, but I've cleared the codes a few times. So u reckon it's gotta be a boost leak?

Definitely... some obvious places to check -

Main boost hoses
WG diaphragm
Bypass valve
WGFV (N75) cracked
Minor hoses often fray and split - and check all teh connections at rear of engine

[Orion]

Is that Wastegate diaphragm? I know where the wastegate is...but not its Diaphragm

[Sleeper_Avant]

id bet on n75 valve damage since its only happened since induction kit came loose, swop it for a "mates" off his urs4/6

[S2central.net]

Is that Wastegate diaphragm? I know where the wastegate is...but not its Diaphragm

Its the membrane that separates lower and upper chamber of the wastegate... a split here has the engine inhaling unmetered air and can give rise to boost cut as a result of excessive pressure on boost.

[Orion]

What would I do without you guys eh...? Thanks muchly everyone. Will go leak hunting tomorrow! Bit dark at the mo lol

[HMS-S6]

If you get nowhere by just looking, see if anyone one here is willing to loan you a boost check kit, used with an airline. And yeh those N75 valves can be brittle, i managed to break a brand new one once