A3 CAYC Boost issue P2563 P2564

[nitemare306]

Hello and help!

I am having a little issue with an A3 mileage is 123924m and its in fairly good condition.

I am getting code P2563 intermittently with low power and P2564 which then seriously reduces power.

I just not really sure where to take the diag next, I have tested the vacuum coming out of what I think is the N75 valve and that is strong, apologies I have lost figures for it but I will retest if required. I have vacuum tested the vane position sensor and that appears to operate smoothly through its range (pressumably its full range) and holds its vacuum okay.
I have looked at all the wiring I can and all seems to be very well, I am unsure what voltage I should be recording at the sensor etc as I am led to believe that you can't get a repair kit for this one.

Am I right in thinking that it may need a reman turbo? I know a decent turbo specialist in Notts but I just wanted to make sure that I have covered all bases before comiting to it.

Also to note, there is some soot deposits around the cat and rear of the turbo, but no obvious signs of any blow? Could this have been caused by overboost maybe?

Thanks for anyone reading who might be able to help.

Mark

[Crasher]

If the turbo specialist is Midland Turbo there is no better company I know of, in fact they are THE best company I have ever dealt with for any service which reminds me I have to go there first thing in the morning to pick up an Audi S2 Liam there has built for me. The fault on yours is likely to be a punctured actuator diaphragm, disconnect the vac hose and apply a vacuum to the capsule, you should not be able to draw any air.

[nitemare306]

Thank you Crasher for the reply.

Yeah its Midland Turbo, are you Notts based then? I have to admit that I haven't used them for a very long time! I hardly ever fix buses or cars now a days (thank god! haha!)

I think I have tested the vacuum on there, I am getting to 400inmg and the lever is moving, once there it stays at 400? I will include a couple of pics if that's okay? Also, not sure if this is a valid test but I put my vac pump on the vac side of what I think is the N75 valve. That refuses to hold a vacuum at all, even if I block the pipe leading to the airbox. But when running it does draw the actuator valve up.


If any of that makes sense!

20240211_161320.jpg20240211_161735.jpg

[Crasher]

Midland Turbo are about two miles away from where I am sitting. If the capsule holds a vacuum then internal carbon build up Amy be causing a feedback error to the ECU or there is a wiring problem.

[mickeybo]

The gauge your using for the vac reading is showing 15 in/hg vac but has to show at least 26/27in/hg .Thats the very most likely cause of not boosting

[nitemare306]

That you Mickeybo, That wasn't measuring the vacuum produced by the car. That was just me pumping down the vane actuator to see if the diaphram was drawing atmosphere. It held pressure okay.

Thank you!

[nitemare306]

Well, absolutely gutted....
Turbo changed for a reman unit and fault is very much still there.

P2563 and flashing coil light. No other faults codes present. Engine isn't revving over 2700rpm ish on driveway. no road test yet.

any other ideas of where to look?

Many thanks

[Crasher]

Turbo by Midland? Take the vacuum source hose off the servo feed pipe and apply a vacuum to it, it must hold air tight.

[nitemare306]

Thanks Crasher,

No the reman turbo was from Turbo Surgery in Peterborough, However it had a new core and looked good at least!

So, it wasn't quite holding a vacuum. I found that it was sucking in through the N75 valve down the hose that leads to the airbox. That happens with the original N75 and a new one I ordered off ebay! BUT not on another one my friend ordered off Amazon! Could that be an issue? Do you think I might need a new Audi one?

Thanks again

[Crasher]

The system must be totally air tight or the ECU can’t control the capsule correctly.