# TT POWER LOSS



## H52 (May 2, 2010)

Hi Everyone

Had an EML on in dash, took it to the guys at a well known Audi specialist. They found it had a problem with the thermostat (spelling lol), booked the appointment to get it done a few days later (they had to order the part). On driving home from the datalog test my 2001 225 TT, remapped, lost its power. I couldn't get it over 50 and when I put my foot down  the TT just held back, almost dying on me, then it would pick back up again but not to it's full power, it then continues like this for the rest of the drive. [smiley=bigcry.gif]

Went back to the well known Audi specialist to get the thermostat replaced and mentioned the power loss to them, they then put it back on the datalog, after replacing thermostat, to check if any other fault codes came up. No fault codes came up so they did a smoke test to check if any of the hoses were leaking etc, but that came back ok. They then said it could be the lumber probe pre cat, but they are not sure so would have to delve deeper to find out what the problem is. Now if it's not the lumber probe I don't want to be left out of pocket with my TT still having the same problem. The guys said the problem is not the remap or the turbo (thankfully). So I thought I'd post here to see if anyone had any advice.
I have read the posts regarding power loss but they don't seem to apply to me as this problem of mine isn't just when the car is cold.
Oh and I am using 99 petrol, if that makes any difference.

Would appreciate any help and advice.

Thanks

H52


----------



## y3putt (Mar 29, 2008)

Ask them to check both the MAF and coilpacks..

Mark


----------



## denimblue225turbo (Aug 28, 2009)

Power loss in a TT is the most common problem but unfortunately it has no definative answer. MAF, MAP, coil packs, boost leaks, N75, D/V, N249, throttle body, dodgy remap the list goes on and on!!! If it's on conciliation mine has started running in limp mode everytime I go to drive it and the air bag light comes on because of the cold weather, so I use vagcom to clear the codes then it's fine again until the next day, luckily I only drive it about once a week :?


----------



## Charlie (Dec 15, 2006)

Sounds like coilpack to me and I have had 4 go in 3 years. It could also be the MAF as Mark suggests and various other things to, the N75 is another contender.

The MAF you can check by unplugging it and if the car starts to perform well then you know to change it (don't drive too long with it unplugged as it will run rich)

The coilpacks are about £37 each from Audi and are a fairly straghtforward DIY job (1/2 easy 3/4 slightly more fiddly)

N75 is about £70 from Audi and a 3 minute job to change.

Charlie


----------



## H52 (May 2, 2010)

Hi
Thanks to all that have given me some advice.

I'm not very technical so please could you explain what the MAF and the N75 is 

Thanks
H52


----------



## Charlie (Dec 15, 2006)

H52 said:


> Hi
> Thanks to all that have given me some advice.
> 
> I'm not very technical so please could you explain what the MAF and the N75 is
> ...


Basically the MAF relates to airflow into the engine and the N75 relates to boost control, if you use the search function you will find many threads on the subjects and also pictures of where they are and how to change them 

If you get really stuck then give me a call in the week on 07814 365147 and I will talk you through exactly where they are and what to do (be standing by your car with the bonnet open if you call me )

Charlie


----------



## H52 (May 2, 2010)

That's brilliant thanks Charlie


If it's connected and if it makes a difference, I have had the Air Mass Meter replaced


----------



## Charlie (Dec 15, 2006)

H52 said:


> That's brilliant thanks Charlie
> 
> 
> If it's connected and if it makes a difference, I have had the Air Mass Meter replaced


I think that air mass meter is just another description for the MAF - did you notice any difference once it was changed? or was it done before you got the car? (if so when was it changed)

Could be N75 - for me when a coilpack has gone, the car has become pretty much undriveable and I have had to limp the car home.

Charlie


----------



## H52 (May 2, 2010)

The problem has only started in the last week, I had the air mass meter changed back in the summer. Only had it changed as it was showing faulty, although had no real problems before or straight after the change.

I think I might look into the N75 problem.

Thanks again for your help


----------



## tony_rigby_uk (Nov 27, 2008)

ok ok ok....

1) DV - my first question is have you changed this to a 007p? you've had a remap, only seems logical it's perished and the diaphram is shot to peices, after all i'm guessing it's a 52 plate thats just had a map... so first place to look is there.
2) MAF - you say it's been changed... by who? how much was bill? cheap MAF's or mass air flow sensors are floating about everywhere, and to find one fail a couple of months after having it replaced doesn't surprise me unless you've paid full price for it..(cheap is exactly that)
3) N75 - this little puppy can cause massive issues. usually followed no specific engine lights on the dashboard, but usually logs a code, (especially if hit into limp mode) by the sounds of it your car could possibly be hitting limp mode and then back up to power...(limp being a low power get me home setting on the engine)
4) N249 - usually associated with turbo noise.. it basically keeps the DV open and loses all your boost.. it may also be flapping on and off causing power loss then power back.. 
5) Coil Packs - may be intermittently losing a cylinder, i would also suggest spark plugs in this category..

so how to check... well...
1) DV test.. take it off push the diaphram up but keep your finger on the nipple at the top.. this should create a vacum and keep the diaphram open when you stop pushing.. if it falls straight back down then the diaphram is leaking.
2) MAF test.. unplug it and go for a spin, (this is the car running on default) if it feels better than with the maf plugged in then your maf needs changing.
3) N75 test - usually done by real time driving logs (N75 duty) but can be very helpful if a boost gage is fitted to see where it's losing power.
4) N249 test - take the pipe off the top of the dv, and follow it to the inlet manifold. once you've found these locations get yourself a peice of 4mm hose and attatch at the 2 locations found.. this will then bypass the N249 and will feel much better if it is the N249 at fault.
5) Coil pack test - engine running, pull them up one at a time, if the engine note changes put it back in.. the failed coil pack is the one that does make a difference.. also i have experienced a coil pack show signs of failure visually... (3 will be silver, 1 will be brown.. it'll be the brown that needs replacing...)

I hope that is of use to you and is in no particular order... my first guess would be coil packs as there very common.. but if it's been looked at by a garage i can't see how thats been missed... all i can suggest is try the ones up there your comfortable doing... and report back... at least we can start to eliminate some of the faults then....


----------



## Wak (May 6, 2002)

H52 said:


> The problem has only started in the last week, I had the air mass meter changed back in the summer. Only had it changed as it was showing faulty, although had no real problems before or straight after the change.
> 
> I think I might look into the N75 problem.
> 
> Thanks again for your help


Where are you based? 
You could end up spending a lot on parts not needed which it sounds like you already may be... Better to go to somewhere that knows what they are doing.


----------

