# Turbo problems



## thehpman (Jul 23, 2010)

Hi all, I'm new to posting on here so bare with. I have bought a 2005 TT Quattro Sport today which I've now got a problem with. There seems to be a serious amount of Turbo surging and stuttering. The car has been at this garage for at least 9 months as I drove it 9 months ago and it was great so I'm not sure if all that time hardly moving has caused this. Sometimes when you drop it down a gear expecting it to just take off it hiccups along because the turbo comes in and out every 2 seconds. I have had this problem in the past with a 2003 180 Roadster but it was less noticeable on that car but we only covered 3000 miles per year so again it was hardly used much like the car I've bought today. The car is going back to the garage under warranty next week but I wonder if any of you experienced TT owners can help point the mechanic in the right direction. Thanks.


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## Hoggy (May 8, 2002)

Hi thehpman, Welcome to the TTF.
Could be just a failing coil pack or MAF, any faults showing up, if not needs VagCom scan.
Disconnect the MAF first & see if that makes any difference.
Hoggy.


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## thehpman (Jul 23, 2010)

Thanks Hoggy. The MAF was my first guess and coil packs 2nd so at least I was thinking along the right lines because I have replaced those 2 things on another car in the past. Is it easy to disconnect the MAF on a TT?


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## thehpman (Jul 23, 2010)

No Faults coming up on the dash by the way. Hasn't been checked on the diagnostic scan yet. Hopefully get that checked next week.


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## thehpman (Jul 23, 2010)

A local garage put the car on a Bosch diagnostic and it came up with "boost pressure exceeded" or something. He cleared that and I have driven about 50 miles today after putting some Millers Oils Eco Power in the fuel tank along with the Super Unleaded and the problem has varied. The turbo flutters a bit but not as bad as the hiccuping on Friday and it sometimes comes in and works fine and then it will almost go off completely.
I've seen on another post from 2010 that it may be the Waste gate Actuator. It will be worth checking the pressure valve first I guess but that's where I'm up to. It will be going back to the garage this week.


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## T3RBO (Dec 9, 2003)

Below guide shows maf disconnection

http://www.wak-tt.com/mafclean/mafclean.htm


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## thehpman (Jul 23, 2010)

Thanks TR3BO


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## Brucekent (May 29, 2011)

On my TT recently I was reading boost preasure exceeded on my vagcom. The car would have lots of boost, then change gear and the boost would either come in and die off or not come on at all. No lights on the dash board. It turned out to be the N75 valve causing the issue. Best bet it to get your car onto a vagcom and then have a look on the full description on ross tech's website


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## Brucekent (May 29, 2011)

Where abouts are you based?


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## thehpman (Jul 23, 2010)

Hi Brucekent,

Thanks for the reply. I think the N75 is was what my local garage was referring to as the boost pressure valve. He showed me where it was and it was at the front of the car opposite the bottom of the front grill and it had a screw on the top of it. Does this sound like the same part? It has a pipe leading to the turbo from it.

I am in the North East mate so not sure if that helps but the car is still under warranty with the garage and they have an Audi dealership next door so if I can give them some ideas it should get sorted fairly efficiently.

I don't think it's a MAF fault because when I've had these on other cars I have had other symptoms like stalling and idle issues. This very much sounds like the N75. I have read that other people have had other things effecting the turbo after replacing the N75 like EGT sensor faults but the diagnostic only picked up a boost pressure exceeded fault so fingers crossed it's a simple N75.

Thanks mate. I'll update the post when I know more; mechanic is calling me tomorrow when he's back from holiday.


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## Brucekent (May 29, 2011)

No worries, were aall here to help with our own previous experiences. To be honest, if you type n75 value 1.8t, it should be able to bring some images with the location of the valve. I was just thinking there must be someone local who'll be able to read your ecu a lot cheaper than a garage or dealership. Let us know how you get on...


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## thehpman (Jul 23, 2010)

Update; as mentioned in my earlier post I have put some 99 octane in the tank which has mixed with a quarter tank of 95 (already in the tank when I bought it) and I also added Millers Oils Eco Power in the tank which has mixed with this for the past few days. I noticed an improvement from when I added the Millers as the hiccuping stopped but the turbo would still sometimes barely spool up at all; however it was important to give it time to let the 95 get mixed and the overall octane raised from the 99 and Millers. I drove 100 miles yesterday and the turbo didn't spool properly on 2 occasions in the whole journey so it has improved significantly from when I first bought the car last Friday.
I'm starting to think this is all fuel related and the fact the car has been sat doing next to nothing on a dealer forecourt for 12 months certainly hasn't helped. Why on earth anyone would put 95 octane in this car is beyond me!
We'll see how it goes for the rest of this week. Anyone else had issues like this on 95 octane?


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## Charlie (Dec 15, 2006)

I hope it is just old fuel buddy and I suppose it is perfectly possible, the symptoms do seem to match up with a faulty N75 valve too. I had a similar problem and it was resolved by changing this part.

I have used 95ron in the dim and distant past and do remember that the car felt less powerful, but it did not result in any hiccuping.

Let us know how you get on and have you tried the MAF disconnect to rule that out or otherwise yet?

Charlie


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## E3 YOB (Mar 2, 2010)

PM me your address. I have a spare N75 which I can post to you which is in perfecting working order. It's no use for me so may as well get a good home, worth a try as it is easy to swap out.

Frase


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## TT51 (Feb 28, 2009)

When mine was holding back and also getting the same fault max boost exceeded it also turned out to be a faulty N75


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## thehpman (Jul 23, 2010)

Thanks Charlie, Frakay and TT51. Because everything has improved over the last few days I'm hesitant to unplug the MAF until I've given it another couple of days. Incidentally here is a link to my recent post on fuel octane levels; viewtopic.php?f=1&t=220075 I thought it was very relevant under the circumstances.

The problem with my TT is not just the 95 octane it's the fact that this fuel has probably been sat in it for best part of 1 year and as the Fuel report mentioned on the other post states; "All petrol fuels suffer olefinic breakdown where the inherent energy level drops over a period of time". This energy level may have got so low combined with rubbish in the fuel lines that it could easily have caused the hiccuping to occur. I have a feeling it's related to the N75 but want to rule the simplest cause out first. It's rare that you find a TT 240 sport that's been sat around for 12 months so it might be a unique issue.

I'll give it a few days and report back mate.

Thanks Frakay, I'll PM you my address mate just in case this problem doesn't rectify itself any time soon.


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## thehpman (Jul 23, 2010)

Frase, I cannot PM you because it says I'm not authorised yet as I need to participate more! Can I email you instead? Can you PM me with your email address or something, although I'm not sure if I can even open PM's either.

Thanks, 
Steve.


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## E3 YOB (Mar 2, 2010)

No probs, i'll stick it in the post for you. Unplugging the MAF is simple btw. It is just a plug on the maf housing you need to disconnect. You don't need to remove the MAF itself so takes a few seconds to test.

I would if it doesn't clear with better fuel then swap out the N75 as this is the likly cause.

frase


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## E3 YOB (Mar 2, 2010)

PM sent


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## thehpman (Jul 23, 2010)

Update; I started to get a 90%+ hit rate with the turbo coming in after a few days of a tankful of VPower and Millers Oils so I was quite pleased. I then booked my car in for the Coil Pack recall where they replaced all 4 coils FOC....that's great but 
the funny thing is that Audi came back with an estimate for other items that need doing and it totalled £850 (AC Compressor and Brake switch) but luckily it's under warranty with the dealer I bought it from.....hahaha, Audi were so desperate to find something wrong with the car and they did but they ain't getting the money......ohhhhh it felt goooood.
Anyway on top of this the turbo had then stopped working again.  I noticed that the trip computer and everything had been reset and I saw the boot lid up in the workshop so I assume they disconnected the battery (battery is in the boot on the sport) to fit the coil packs. I'm wondering whether this has set me back due to the ECU memory being cleared or something??
I put some Tesco momentum 99 in yesterday and it's been 40% at best. I've got it booked in at the garage I bought it from to get the AC Compressor and brake switch fixed and I've asked them to look at the N75 and MAF to get this sorted once and for all.
Any fresh ideas from anyone please? I guess I just need to wait and see what they find in a few days.


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## antcole (Apr 4, 2009)

thehpman said:


> Update; I started to get a 90%+ hit rate with the turbo coming in after a few days of a tankful of VPower and Millers Oils so I was quite pleased. I then booked my car in for the Coil Pack recall where they replaced all 4 coils FOC....that's great but
> the funny thing is that Audi came back with an estimate for other items that need doing and it totalled £850 (AC Compressor and Brake switch) but luckily it's under warranty with the dealer I bought it from.....hahaha, Audi were so desperate to find something wrong with the car and they did but they ain't getting the money......ohhhhh it felt goooood.
> Anyway on top of this the turbo had then stopped working again.  I noticed that the trip computer and everything had been reset and I saw the boot lid up in the workshop so I assume they disconnected the battery (battery is in the boot on the sport) to fit the coil packs. I'm wondering whether this has set me back due to the ECU memory being cleared or something??
> I put some Tesco momentum 99 in yesterday and it's been 40% at best. I've got it booked in at the garage I bought it from to get the AC Compressor and brake switch fixed and I've asked them to look at the N75 and MAF to get this sorted once and for all.
> Any fresh ideas from anyone please? I guess I just need to wait and see what they find in a few days.


Thats weird.... someone else on here was in for their free MOT the other day, passed and went back a couple of days later for some minor item... they also found 'extras' to be done... brakes etc.... quoted him exacly 850 quid too....

Is it a campaign by UK Audi dealers to get exactly 850 quid from otherwise perfect customers???

Sorry, its not really relevent to your question... just thought id add that!


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## R80RTT (Feb 5, 2011)

WAs this bought from Redline Racing?


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## thehpman (Jul 23, 2010)

R80RTT said:


> WAs this bought from Redline Racing?


Yes mate it was, why?


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## thehpman (Jul 23, 2010)

Antcole, I made a comment on this on page 42 of this thread.http://www.********.co.uk/forum/viewtopic.php?f=2&t=193537&start=615
I agree, it's a bit suspicious. It's almost like Audi have done the recall to get older cars in so they can get some out of warranty work out of it!!


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## R80RTT (Feb 5, 2011)

I nearly swapped that TT for another car... Turned up at the garage, has no MOT and had no Service. They then sent it off to be sorted. Your Warranty I believe is with Warranties 2000. Make Sure you take it straight back to get sorted.


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## R80RTT (Feb 5, 2011)

Sounds like they have done completly nothing on the car. I ve bought one before from them, a Subura Impretza paid top money, took it to Subaru, and everything was wrong with it. They do seem a good set off lads, but it does show, why people, part ex there cars.


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## thehpman (Jul 23, 2010)

R80RTT said:


> Sounds like they have done completly nothing on the car. I ve bought one before from them, a Subura Impretza paid top money, took it to Subaru, and everything was wrong with it. They do seem a good set off lads, but it does show, why people, part ex there cars.


It's possibly going in today to get sorted. The bugger was that Redline hadn't even bothered checking for any recall work even though the Audi garage is right next door! They should have known there would be problems with the car because it's been sat around so long on their forecourt. The N75 and AC Compressor are typical examples of thinks seizing up after not being used often enough. We'll see what happens after it goes in. I guess in theory I could have got this work done by my local garage and claimed under the warranty? Not sure If I had to take it back to them.


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## thehpman (Jul 23, 2010)

Update; I've got the car back today after the N75 has been replaced and it's great and consistent. It's now fairly obvious to me that the N75 was causing the turbo to over boost which was then being picked up by the ECU which then dropped the turbo completely for a set time period. I can now notice that when the turbo comes in now it's not boosting as much as before because it's not quite as quick but at least it's healthy.


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## landwomble (Feb 9, 2011)

I must say, the that was fairly apparent from your first post. Low octane fuel was a bit of a stretch...

Sent from my HTC Desire using Tapatalk


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## thehpman (Jul 23, 2010)

Yet another thing I had to have replaced was the battery. It went dead after only 1 month of long trips. Didn't hold it's charge (after recharging) for more than a day when not driven. Looked in the boot at the battery and someone at some point had put some cheap battery in it (make was Planet). I spoke to Redline who got me a genuine VAG one under warranty. All sorted again. So within 2 months I got;
4 new coil packs (from Audi)
N75 Valve
AC regassed
New brake switch
New battery
radio decoded they didn't have the code and as the battery went dead...........
New car manual - well this hasn't arrived yet as there wasn't one with the car.

Much of this list is down to the car been sat around for so long but you would have thought they could have been arsed to order the manual at some point over the 12 months it was sat around!!


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## Nick 225TT (Jun 6, 2008)

thehpman said:


> A local garage put the car on a Bosch diagnostic and it came up with "boost pressure exceeded" or something. He cleared that and I have driven about 50 miles today after putting some Millers Oils Eco Power in the fuel tank along with the Super Unleaded and the problem has varied. The turbo flutters a bit but not as bad as the hiccuping on Friday and it sometimes comes in and works fine and then it will almost go off completely.
> I've seen on another post from 2010 that it may be the Waste gate Actuator. It will be worth checking the pressure valve first I guess but that's where I'm up to. It will be going back to the garage this week.


This sounds very like the N75 to me I had the same issues see all of this post ....

http://www.********.co.uk/forum/viewtopic.php?f=2&t=218343

I got a replacement from ebay took all of 10 mins to fit and cost £40 delivered sweet

http://www.ebay.co.uk/itm/260840680580


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