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Flat Spot TT225


Braytak
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Hi

As a Cab owner I address the TT Forum with humility and mucho respect.After all we are all part of the Family..

Could you guys answer this question.

My Cousin has just purchased a nice 225 TT on a W plate.

The car is very fast but has a flat spot or hesitation at around 4000-5000 under acceleration. It then picks up again and flies basically.

Any help or advice gratefully passed on.

All the Best.

Gez notworthy.gifnotworthy.gif

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Hi mate,

From my previous experiences with the 1.8T engine it could be a duff DV or the inlet pipe on the Turbo itself has busted. Install a new Forge DV first and see if that is it.

Or could be the ECU itself needs reseting as been as it is a W reg and probably been fiddled with over the years as such.

Hope this helps as I am new to the TT too.

Cheers

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Hi Chad.

Thanks for the info, am I completely Dumb!....does DV mean (Dump Valve) roughly how much is one of these components and can it be owner fitted.

Do you mean the car could have been chipped before my cousin bought it or has someone possibly made other mod's.

Cheers.

Gez.......... confused.gif

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Flat spot between 4 & 5k sounds like it could be 'collapsing hose syndrome'.....4900 ish to be more precise.

That the car overcomes this flat-spot and then proceeds to rev again is less indicative of this problem. Get your mate to try it at full acceleration and then on a part throttle to see if he can rev cleanly through the 'spot'. If the problem arises on full throttle but not on a part-throttle then it may well be the hose.

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Gez,

Yes I meant Dump Valve, tell them to get the Forge aliminium one, if anything it will help, in that it will never break!

As for the ECU, well I have heard of peoples having to be reset over time, if indeed it has been chipped and the original has been put back in.

Saying that mine is a 52 reg (only done 1300 miles!) but some days feels sluggish between 3000 and 4000 revs.

Fianlly, heard one about a Throttle body reset on the TT, whereby you just turn the ignition on for 3 mins. This will reset the way the car has learnt how you drive, so if you are stuck in traffic everyday then the car will start to get more and more slugish due to the limited use of the throttle. After the reset you will again get the full throttle range so you get that just been serviced feeling. Mentioned this to a dealer expecting the blank Homer Simpson expression but instead got the reply 'yeah not everyone knows about that...'....

Cheers

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[ QUOTE ]

Fianlly, heard one about a Throttle body reset on the TT, whereby you just turn the ignition on for 3 mins. This will reset the way the car has learnt how you drive

[/ QUOTE ] oooo i never knew that either.... thought that resetting the ECU did the same job? i will try it out on my S3 tomorrow. beerchug.gif should be the same a TT.

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[ QUOTE ]

[ QUOTE ]

Fianlly, heard one about a Throttle body reset on the TT, whereby you just turn the ignition on for 3 mins. This will reset the way the car has learnt how you drive

[/ QUOTE ] oooo i never knew that either.... thought that resetting the ECU did the same job? i will try it out on my S3 tomorrow. beerchug.gif should be the same a TT.

[/ QUOTE ]

Yep, just make sure you only turn the ignition on and not the engine for about 3 mins. you might hear some clicking in the background, can't say I did.

Do not know whether it was psychological or what, but was pretty sure the throttle was more free reving than before, thus the car seemed more lively than before.

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Yeah, some people say it works, some don't. confused.gif

Very sceptical myself but it is so simple you just end up trying it!

My journey to work is relatively short but has a lot of stop/start mingingness to it, so guess my TT will get relatively sluggish over time. Gonna try this again at the weekend, before I give it a good run and see what it does.

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Am a bit sceptical about the whole thing.

I can't believe that if I tootle around for a few weeks and then suddenly put my foot down I won't get the full 225 horses.

I know engine wear and running in can affect this but that's over 10s of thousands of miles.

Apparently the throttle learns your driving habits but surely it doesn't withold power from you if you normally drive more slowly. confused.gif

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I dont think it actually reduces the bhp.

I think the car/ecu learns how you use the throttle (pedal) i.e. fast/slow etc and the VVT adapts to this.

So i think by resetting the throttle the ecu will relearn this again from scratch, what the means is that the accelerator is back to oem/max sensitivity..... once it picks up your driving style again the sensitivity will lessen.

Just a theory. pengy.gif

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Ok,

Here goes. Forgive the pigeon mechanics at work here. The throttle body adjustment will only make a difference if prior to the adjustment your throttle was actually in need of re-calibration!

IIRC correctly (i was told once) the drive by wire throttle has something like 256 different states that equate to 256 different throttle positions i.e. 0 closed, 256 full open and everything in between. If the throttle body has for whatever reason fallen out of synch it might be that you're requesting full throttle and the car is only computing position 245. Thus, the adjustment/recalibration process takes about 3 mins and slowly moves the throttle from fully open to fully closed and in the process sets the correct '0' and '256' once again. This should ensure that when you ask for 256 you get 256!

I'm sure thats what i was told!

Hope it makes sense. I'd laugh if it was entirely wrong though yelrotflmao.gif don't think it is mind.

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