# LOSS OF POWER WHEN ACCELERATING.ENGINE HESITATES



## zook (Aug 4, 2008)

Hi There,

I've just bought a used TT and so far its been great, theres just one problem I need some advice over and thought this was a good place to start to get some ideas!

The acceleration has always seemed quite poor since I bought It and there has never been that much power when accelerating/speeding up. More recently when I speed up in first and second gears the engine starts to accelerate and then seems to drop out and lose power temporarily then kicks back in again.This seems to happen more often when I'm driving it for the first time in the day. Also when I start my engine it seems to chug a little and revs on its own until it becomes constant after that it seems to balance out a stabilize.

Does anyone have any ideas as to what the prob might be and if so Is it something I can fix myself? Some ideas I have had (coil pack? Mapping? Spark plugs? Exhaust?)

Any feedback would be greatly appreciated.

Thanks

Zook


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## anty1985 (Oct 5, 2007)

I would say n75 valve or coilpacks issue. Someone will be along soon to confirm my thoughts 

Not that expensive to fix thou


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## Harv3y (Jun 2, 2008)

I would think either as anty said coil pack or N75 they are both prone to fail..

Have you checked all your hoses for splits or leaks may be a boost leak??

I hope you dont put your foot down when the engine is cold....

Do you have VAG COM to run a diagnostics?


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## VinTT (Sep 10, 2007)

> Also when I start my engine it seems to chug a little and revs on its own until it becomes constant after that it seems to balance out a stabilize.


Is this normal?? I also noticed this on mine when starting the car from cold. Will take about 20secs to stabilise?... :?


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## joesefk (May 28, 2008)

i think its more likely to be the Air Mass meter, try disconnecting the wiring from it and drive the car, if it drives smoother, then this is the most likely culperit


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## ttsteve (Nov 1, 2007)

I think it's the MAF.


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## goodbrand (Mar 19, 2007)

could also be ur dv is sticking!!


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## joesefk (May 28, 2008)

Never heard of a DV sticking before [smiley=book2.gif]


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## Motorhead (Mar 25, 2007)

joesefk said:


> Never heard of a DV sticking before [smiley=book2.gif]


They can stick, however this is usually in cold climates..


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## goodbrand (Mar 19, 2007)

Motorhead said:


> joesefk said:
> 
> 
> > Never heard of a DV sticking before [smiley=book2.gif]
> ...


I thought as much  Glad someone proved me right :lol:


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## joesefk (May 28, 2008)

Not possible with a Forge DV,

Cant see how the original Bosch unit with a Rubber Diaphram can 'Stick' [smiley=gossip.gif]


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## goodbrand (Mar 19, 2007)

joesefk said:


> Not possible with a Forge DV,
> 
> Cant see how the original Bosch unit with a Rubber Diaphram can 'Stick' [smiley=gossip.gif]


he said he has just bought it 2nd hand, so chances are he doesn't have a forge DV, and will have the bosch rubber/plastic oem one!! Like the one I am about to replace for a Forge DV for the same reason!!!

I have checked wih VAG-COM for faults such as MAF and other sensors...


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## zook (Aug 4, 2008)

Harv3y said:


> I would think either as anty said coil pack or N75 they are both prone to fail..
> 
> Have you checked all your hoses for splits or leaks may be a boost leak??
> 
> ...


Thanks for the advice guys... 
could be the N75 or coil pack then.

Do you guys know how much it would cost to repair N75 or coil pack or are they easy to fix myself?
and how much would the parts cost??
Where should I look for a boost leak and split hoses?

Also just checked out the VAG COM online.Looks like it could be quite a useful tool!
Do you know how much it costs/the best place to get one? Is it worth buying one?
Is it easy for a novice to use? and would it give me a definite answer to what this issue might be?

Thanks again! (quite a few questions I know!)


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## zook (Aug 4, 2008)

joesefk said:


> i think its more likely to be the Air Mass meter, try disconnecting the wiring from it and drive the car, if it drives smoother, then this is the most likely culperit


Hi Joesefk, Where is the Air mass meter located?? Anywhere I can find a photo to see where it is???

Cheers

Z


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## Adam RRS (May 25, 2006)

On the side of the airbox with a plug going into it.....

The symptoms yr car is showing is EXACTLY what happens when the MAF is faulty!

£75-80 to replace on an exchange basis with Audi/Euro Car Parts/GSF etc


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## Rosskie (Jul 31, 2007)

Zook,

I had those symptoms and replaced the MAF with an Audi part, and its still the same.

Could well be another faulty MAF... It not N75, thats also been replaced.

Have to look at DV too.

Unlikely to be coils as it always happens at a very specific point in the rev's. You should be able to rule them out if your hestitation is at the same point.

You an APX or BAM? Remapped or Stock?


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## joesefk (May 28, 2008)

It would be worth having the throttle body cleaned out and then VAG COM connected to do a throttle body reset and do a 'factory settings' reset,
Also dont forget to change the sparkplugs if they aint been changed, NGK are recommended.
All else fails i think i could be a start of one of the coil packs going down


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## zook (Aug 4, 2008)

Adam TTR said:


> On the side of the airbox with a plug going into it.....
> 
> The symptoms yr car is showing is EXACTLY what happens when the MAF is faulty!
> 
> £75-80 to replace on an exchange basis with Audi/Euro Car Parts/GSF etc


Thanks for that. Is there a way I can tell its faulty or not by taking it out and looking at it??


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## LuTTon (Jul 18, 2008)

zook said:


> Thanks for that. Is there a way I can tell its faulty or not by taking it out and looking at it??


Nah 'fraid not but I've got exactly the same problems (started playing up just before I went to the Ace cafe meet so thanks to the guys there for the advice) and I've just picked up a replacement at my local GSF ( http://www.gsfcarparts.com ) for £58. They will charge you an extra £20 and then refund it when you give them your old faulty sensor, I've just fitted the CDA airbox so I quickly took it all out there and then so I didn't have to worry about going back!

Does anyone else know if this will cure the problem instantly or will it take a few runs to sort itself out?


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## LuTTon (Jul 18, 2008)

zook said:


> Thanks for that. Is there a way I can tell its faulty or not by taking it out and looking at it??


Actually I may be wrong, if you know what your looking for you can tell if its not functioning correctly using VAGcom (I think)

I've also been told that its worth-while keeping a spare coilpack handy since they seem to go on a regular basis!


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## joesefk (May 28, 2008)

There isnt a 'one' fault that fixes this fault on every TT, there is so many different diagnostic result interpretations, that every car needs so be looked at as an individual. Air leaks in either the boost side and or the breather system seem to also a common cause [smiley=book2.gif]


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## zook (Aug 4, 2008)

Thanks for all the feedback, I've got alot to go on now.

Cheers

Z


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## SaintScoTT (Jun 27, 2008)

I've had something similar go wrong with my TT too 

At first I thought it was some bad petrol but its happened twice now, once tonight and once roughly six weeks ago. Its really strange - girlfriend describes it as 'its chugging away quite unhappily'. Go figure. I couldn't accelerate at all, it was doing steady 4k.. I put the accelerator all the way down and .... nothing. Nothing happened! :evil: About ten seconds later it cleared and then it happened again .. pulled over and the idle revs dropped to ~400 when the car started shuddering .. put accelerator down .. nothing.. then five seconds later the revs went up like nothing went wrong in the first place! Pulled out, got it to about 40kph and then it happened again for another 5-10 seconds, then .. good again.

Got home and its fine again. First time I did it I took it straight to the mechanic and naturally it was fine again. sigh!

Would a faulty MAF be like this? Bad then good again? Its only happened twice in six weeks  Had timing belt/water pump changed about 2 weeks before it happened the first time? possibly related?


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## iangoddard (Nov 27, 2007)

Had the similar problem with a different car (focus st170)- ended up that the car was running in 'safety mode' for some strange reason and would not let me go about 3500 revs. Chugged around like this. Some days it was fine and others not. Dont know if there is a similar thing on the audi's. I think there is on vw's, Who knows
May just be speaking a load of crap - just thought it worth a mention!


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## iangoddard (Nov 27, 2007)

Had a scout round the net after my previous post. Safety mode on the ford is know as limp mode for audi. this is the explanation it gives

_*Limp Mode is a default set of values stored in the ECU non volatile memory. If the ECU senses a sensor value missing or out of programmed range, the CEL will illuminate and the ECU will shift to these values to allow the engine to run at reduced power to "limp" to a service facility without further damage to the engine.*_

Like i said not sure if this is of any use. Other sites mention faulty valves etc. Are the cars that are having a loss of power running an engine without mods?


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## SaintScoTT (Jun 27, 2008)

only performance mod I've done is a K&N panel filter.. thats about it :\

hasn't happened again  maybe its the MAF? I dont know!


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