# Mk 1 tt idle problem



## myauditt225 (Nov 6, 2011)

Hi guys i just bought myself an 02 1.8 tt,first audi i have ever owned as i have always been been a vauxhall man (just got rid of my calibra turbo) so i thought i would join a forum just in case.
First thing i had done was the coil change at my local audi dealer FOC courtesy of the info i picked up on here and i have just changed plugs and air filter but this hasnt cured the fluctuating idle,its not that bad but i want to try to sort this out and was wondering what to try next as this car is a bit more advanced than the calibra i have sold.
cheers
colin
Oh great site by the way seems like theres a lot of people on here that know what they are on about


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## TT-1 (Oct 25, 2011)

I asked the same question after I bought mine a few weeks back. My idle is not rock solid, it moves ever so slightly. Apparently this is normal. The two TT I have drove on my test drives did the same also.


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## myauditt225 (Nov 6, 2011)

ok thanks for that.Its just a bit of a niggly thing really ,i thought it could be a vacuum pipe or idle valve,other than that the car runs fantastic,a bit better than the calibra :lol:


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## Hoggy (May 8, 2002)

Hi myauditt225, More likely the throttle body requires a clean.This "How To" is not for TT 225 but same procedure.
http://uk-mkivs.net/forums/t/127279.aspx
If this doesn't cure it disconnect the MAF, if that cures it replace the MAF
Hoggy.


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## TT-1 (Oct 25, 2011)

I bought a cable the other day that allows me to look at the idle speed and ignition advance along with hundreds of other things going on. I was quite surprised at how little ignition advance is dialled in at idle so I would think maybe with a little more ignition advance this could be improved. But you are right it a niggle. My previous car was a beamer six cylinder and that was rock steady even if you sat there switching on and off fans etc. But that said the 1.8 TT beats my 3.0 BMW hands down


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## TT-1 (Oct 25, 2011)

Hoggy said:


> Hi myauditt225, More likely the throttle body requires a clean.This "How To" is not for TT 225 but same procedure.
> http://uk-mkivs.net/forums/t/127279.aspx
> If this doesn't cure it disconnect the MAF, if that cures it replace the MAF
> Hoggy.


Thanks Hoggy, added to my todo list when I remove the inlet manifold to polish or spray it, haven't decided whether to go shiny or black.


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## Hoggy (May 8, 2002)

TT-1 said:


> Thanks Hoggy, added to my todo list when I remove the inlet manifold to polish or spray it, haven't decided whether to go shiny or black.


Hi TT-1, shiny would look best.. 
Didn't go much on your Ign advance answer..  :wink: :wink: 
Hoggy.


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## myauditt225 (Nov 6, 2011)

Thanks for the replies and info i might try a few things the weekend and im sure i will be posting on here again for advice .
I was wondering if its worth adding some injector cleaner to the fuel,if so can anybody recommend any brands i could use


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## TT-1 (Oct 25, 2011)

Hoggy said:


> TT-1 said:
> 
> 
> > Thanks Hoggy, added to my todo list when I remove the inlet manifold to polish or spray it, haven't decided whether to go shiny or black.
> ...


Yep but does it stay shiny for long 

Ignition advance at idle on mine was around 3degrees. Typical settings on cars I have tuned are 6-10degrees. My Westy is running 16 degrees but then it has a wild cam installed. But I know little about the VAG engine. Can anyone recommend a good source of information.


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## wazman999 (Oct 25, 2011)

Hi,

I had a similar problem. My revs would sit comfortably just below 1000. Then, all of a sudden, they'd drop to just above 500 and the car would feel like it's about to stall. Then they'd immediately pick back up to just below 1000.

I went to my local independant garage, and he reset the Audi settings ( as apparently they can be lost over time ) this meant the engine management knew again when to combine oxygen with the petrol in the combustion process and now it's good as new! Better still, the bloke did it for nothing!


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## Pj mac (Jan 10, 2016)

Hi, my mk1 tt 225,idle when warmed up idles from 660-720 which makes it sound a bit lumpy,disconnected maf made no difference, its returning by the dash 33mpg which I wouldn't hav thought it was maf too get that good mpg, replaced over last couple years all sensors, am I right in thinking if vacuum leak it will be around the intake manafold area


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## Hoggy (May 8, 2002)

Hi PJ, Erratic idle is usually caused by air leaks on pcv hoses below inlet manifold & hoses from cam cover causing weak mixture. MAF doesn't usually affect idle.
Hoggy.


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## Pj mac (Jan 10, 2016)

Cheers will have a good look over the weekend I have replaced most with silicon hoses,except the pain in the arse ones too get at


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## Van Well (Apr 8, 2017)

Hoggy said:


> Hi PJ, Erratic idle is usually caused by air leaks on pcv hoses below inlet manifold & hoses from cam cover causing weak mixture. MAF doesn't usually affect idle.
> Hoggy.


Yep, I second this. I checked and replaced all kinds of things chasing down my rough idling. I even repaired parts of the PCV system under the inlet manifold (Without removing it, which was tricky) but eventually when the inlet manifold was removed to gain total access, I found more split hard plastic hose. Check the entire vacuum breather system because there are many possible leak points, lots of check valves, etc. For example, the brake vacuum line which feeds off the hoses under the inlet manifold, goes along the firewall behind heat shield - there is a check valve under there that may fail.


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## Pj mac (Jan 10, 2016)

Had all pipe work apart under intake manifold, found surge pump was blocked on the take off too pcv valve, replaced with genuine part, new clips where needed, the 2 hard plastic pipes one has a check valve does that go into manifold or to servo as since started it up have abs light and traction lights on,cant seem to find any clear pics


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## davebowk (Aug 16, 2019)

The straight through goes to manifold the T off to brake servo.

Starting the job myself in about half hour


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