Audi S3 - Turbo Issues

[scotty dugg]

Hi all,

Though this deserved it's own thread instead of being buried in my progress thread. Looking for some assistance on fault finding as trying to resolve this without going for a new turbo.

Car:
Audi S3 57' Plate 30k miles, car bought with no service history and had sat some time before purchase.

Issues:

• Car is under boosting .95 instead of 1.2.
• Car is boosting late @4krpm instead of 3krpm.
• As expected MPG is not great, barely breaching 29.0mpg on a long motorway run.
• Very apparent the car is not performing as it should be.

Also fitted a Revo CAI before I knew about this, which threw up sporadic EML's so this is now sold and the EML issue has gone with it after reverting back to standard engine cover.

Current fixes (so far):

• New PCV/PCV Gasket
• New turbo to exhaust gasket
• OBD and VCDS scans show 'Bank 1 Lean' when EML was coming on (only when Revo fitted).
• Cleaned MAF
• New spark plugs

Does it sound like the turbo is seized up from having sat?
Do the vanes within the inlet manifold seize up and cause similar issues?

Any help very much appreciated, this on top of needing a new clutch are really making me regret selling my old car. Just want it fixed so I can enjoy it!

Cheers all,
Scott

 

[S3Alex]

Doesn't sound like it's siezed as you'd get no boost at all.

The runner flaps do cause problems,but also will throw a warning visible on VCDS.

As it's running low boost,one possibility is the wastegate is partly open or the actuator is not functioning properly,and losing boost that way.
Also look at the N75 valve,and for any leaks along the piping to/from it.
Really needs a trip to a decent tuner,to log it and see what the car is requesting Vs what's being delivered,and to look at fuelling as well.

 

[audismart]

Coil packs could be an issue, but as Alex said, needs a decent tuner and mechanic to give the car a vcds check and start fault finding, or you could get lots of things changed and spend a fortune for nothing.
Had a guy on the other day with boost issues and it turned out to be a loose hose. Here is the thread.
Underboost issue? | Audi-Sport.net

 

[scotty dugg]

Doesn't sound like it's siezed as you'd get no boost at all.

The runner flaps do cause problems,but also will throw a warning visible on VCDS.

As it's running low boost,one possibility is the wastegate is partly open or the actuator is not functioning properly,and losing boost that way.
Also look at the N75 valve,and for any leaks along the piping to/from it.
Really needs a trip to a decent tuner,to log it and see what the car is requesting Vs what's being delivered,and to look at fuelling as well.

Thanks Alex, I think there was a pre-existing runner flap fault when we got it but it's never shown again since resetting. It's been scanned a fair few times since.

I replaced with a new revision diverter valve, with the little paperwork I got and looking at the wiring, this is an old unresolved issue. I've a receipt for turbo wiring being fixed last year but no more information sadly.

Is the N75 an easy swap? Looks about £30, one of the things we'd been looking into. Actuator/waste-gate easy changed as well?

Haven't the facilities myself to do a boost leak smoke test but a garage can borrow the kit for me to test it.

 

[scotty dugg]

Coil packs could be an issue, but as Alex said, needs a decent tuner and mechanic to give the car a vcds check and start fault finding, or you could get lots of things changed and spend a fortune for nothing.
Had a guy on the other day with boost issues and it turned out to be a loose hose. Here is the thread.
Underboost issue? | Audi-Sport.net

Thanks Audismart, I've had the pipework visually inspected but not smoke tested yet. Also the VCDS isn't throwing codes now the Revo CAI is off.

Really not sure who I'd take it too yet, the last mob were good but they were the one's saying my turbo could be partially seized.

 

[audismart]

The new revision diverter valves are more reliable than the old diaphragm version, but the do leak boost pressure, you might want to think GFB DV+ later down the line.
Wonder if it might be worth spraying some wynns turbo cleaner into the system?

 

[grainqey]

My money is on a pipe being loose/split like a vacuum leak, you get alsorts of funky fault codes and problems with that vacuum pipe disconnected on the side of the intake manifold so look round at all the vacuum hoses.

The wastegate is not really do-able with the turbo on the car as the driveshaft and turbo bracket/pipes are in the way plus its a mare to get the BCS pipe off of the wastegate actuator.

 

[scotty dugg]

Thanks guys, I'll get it booked in for a smoke test on the boost pipes then, may try some of that turbo cleaner as well for the sake of 8 quid.

Got side tracked and started reading about checking actuator movement and DIY turbo cleaning.

Is the N75 an easy change? (Is that the turbo actuator? if so Grainqey's already answered my question)

 

[S3Alex]

It's the valve that effectively controls the actuator and it's a pain to get to.

 

[audismart]

It's the valve that effectively controls the actuator and it's a pain to get to.

Its on the turbo itself isn't Alex?

 

[scotty dugg]

It's the valve that effectively controls the actuator and it's a pain to get to.

Its on the turbo itself isn't Alex?

Cheers guys, as feared. In the process of booking the car in for a boost pipework leak test. Will be towards the end of the week, I'll update with any results.

 

[S3Alex]

Its on the turbo itself isn't Alex?

Yes unfortunately

(But as you've guessed,not on mine LOL)

Seriously though good luck and hopefully just a leaking pipe.

 

[Smirky]

I had boost issues over boost though so much so that it was going off the map sensor ,
Tried the n75 valve and no joy according to amd the n75 valve is maybe 2 outta 10 the problem ,
Hefty labour charge to change it ,.
So I was left with changing the actuator or changing the turbo went for the turbo just to be on the safe side labour cost wise

 

[scotty dugg]

I had boost issues over boost though so much so that it was going off the map sensor ,
Tried the n75 valve and no joy according to amd the n75 valve is maybe 2 outta 10 the problem ,
Hefty labour charge to change it ,.
So I was left with changing the actuator or changing the turbo went for the turbo just to be on the safe side labour cost wise

Cheers Smirky, that's what I thought it might be, for all the effort to get the turbo out you're as well changing it for a re-conditioned unit.

I'll wait and see!

 

[Smirky]

Cheers Smirky, that's what I thought it might be, for all the effort to get the turbo out you're as well changing it for a re-conditioned unit.

I'll wait and see!

Yep turbo was just over 800 from Audi plus a bit more for pipes etc and ofcourse oil change