Car accelerates as I come off the gas!!???

[VWellsy]

Anyone give me a few clues on this one....(hope it's in the right section )

The car is a 55 plate GTi running REVO Stg 1 (B8 T4 F8), and a full Induction system. It's still on the old DV (which i'm planning on upgrading soon when I get my Turbo back exhaust fitted  )

Also I only use Shell V-power so fuel quality shouldn't be an issue.

What I've noticed is if I boot the car on full throttle then it picks up nicely and seems to accelerate quite hard. Then if I'm catching up the car in front I start to ease up on the accelerator and the car feels like it's accelerating even harder until I lift off a bit further on the accelerator!!!!

Feels a bit odd but I swear the seat of the pants feeling is spot on, haven't got any technical data to back up my hunch though 

My thoughts:

Could it be the DV not holding the boost?
Is the REVO Boost setting to High?

Or is something else max'ing out and causing the ECU to pull back a little???

Just want to see if you guys have had anything like this and what is the likely problem.

[gti265]

i belive i have the same thing, i just assumed it was the dsg gearbox doing somthing but iv never realy worryed about it just got used 2 driving with it, dnt notice it anymore, but if someone knows the reason that would be great :)

is yours dsg vwellsy??

tom

[Top Cat]

Anyone give me a few clues on this one....(hope it's in the right section )

The car is a 55 plate GTi running REVO Stg 1 (B8 T4 F8), and a full Induction system. It's still on the old DV (which i'm planning on upgrading soon when I get my Turbo back exhaust fitted  )

Also I only use Shell V-power so fuel quality shouldn't be an issue.

What I've noticed is if I boot the car on full throttle then it picks up nicely and seems to accelerate quite hard. Then if I'm catching up the car in front I start to ease up on the accelerator and the car feels like it's accelerating even harder until I lift off a bit further on the accelerator!!!!

Feels a bit odd but I swear the seat of the pants feeling is spot on, haven't got any technical data to back up my hunch though  

My thoughts:

Could it be the DV not holding the boost?
Is the REVO Boost setting to High?

Or is something else max'ing out and causing the ECU to pull back a little???

Just want to see if you guys have had anything like this and what is the likely problem.

If you have a DSG box, then what you are describing is the kick down feature. If you put your foot all the way to the floor it gets to the bottom and then clicks a little bit more, Basically it will accelerate fast in the gear you had it in all the way until you click it that last bit, at which point it automatically drops the car down to the lowest gear it can do safely, giving you maximum available speed.
This feature is for overtaking really in D-mode.
You are probable tootling along in 4th floor it and without noticing the DSG has dropped you into second, so when you then ease off a bit you now 3/4 throttle in second at about 5000 RPM.    thats why it is accelerating fast.
To simply avoid this, dont push on the pedal to hard near its full travel.  

And if you dont have DSG i havn't got a clue.  

[VWellsy]

Yep I've got the DSG gearbox but it's not the kickdown feature TC as i'm pretty familiar with that...

Perhaps I've not explained myself very well    I can push the pedal down all the way until it reaches the stop (just before the kickdown happens), and if I lift off the accelerator slightly from that point I can then feel the car start to pull a little bit harder again.

It's as though on full throttle (without kickdown) something has reached it's limit and the car holds back slightly - not as you can really tell at this point cause it goes pretty well anyway. But as you start to lift off slightly (say at 80 - 90mph (on a road in Germany....Uh Ummm  )) then you feel a bit more of a push before you come further off the throttle and the acceleration eases off.

Don't tend to use the kickdown feature as I use the paddles or the gearstick in +/- most of the time.

All of this is only subtle but I can definately feel something is going on, so just wondered what the thoughts were and if there is something worth checking.


Hope that explains a bit better

[Top Cat]

This is just a stab in the dark, but isnt there some sort of throttle angle sensor that can be reset. Maybe its something to do with that. 

[VWellsy]

Thanks TC, that's well worth a look. 

Gonna try and pop down to my local(ish) tuning company APD and see if they can find anything.

If it was the DV starting to fail what symptoms would I get.... Can't wait to get that replaced

Thanks for your help

[Top Cat]

It certainly wont be going faster with a fooked DV. 

Symptoms of the DV ripped are loss of boost over 3000rpm or just general sluggishness, a lot of people dont even know its split. 

[VWellsy]

Cheers TC, good info... 

Not convinced it's the DV then cause it certainly doesn't feel sluggish as it pulls through the 3000 mark. 

Will try and get it checked out later this week and post the results

[Richn83]

This is just a wild guess, but could it simply be that at full throttle you arent able to get enough air through for the amount of fuel you are injecting, so your AFR might be sub-optimal, and once you back off (but still have your foot 3/4 planted) the AFR then reaches a more optimal level and this is giving you the power surge?  This is just a completely out there suggestion, so please feel free to shoot it down. 

[john_o]

ok Ill have a stab
needs logging with VCDS
Id also be seeing if the symptom happens in stock REVO mode
you can check throttle angle (2 sensors in the pedal) to confirm/rule out the pedal itself

I would be thinking
a) REVO settings if it happens in mapped but not stock mode
b) pedal or maybe something like a leaking fuel injector if it happens in stock mode too

other thing to consider is that its nothing to do with the engine(which is running fine)
but the 'effect 'you feel is knackered engine mounts allowing excessive rock ???

[TonyZed]

Thanks TC, that's well worth a look.  

Gonna try and pop down to my local(ish) tuning company APD and see if they can find anything.

If it was the DV starting to fail what symptoms would I get.... Can't wait to get that replaced

Thanks for your help

Have you any news on this? I have exactly the same symptoms. It is a really weird feeling.

Also, although I'm not sure it is connected, when pulling away from cold in the morning the car hunts a bit. Both of these things are quite recent, at least I have only noticed them over the last few weeks. Any ideas out there appreciated.

TonyZ

[waring192]

Possible clutch slip? I know im running a group buy but one symptom is coming of the peddle the clutch has a chance to engage better...

[TonyZed]

Possible clutch slip? I know im running a group buy but one symptom is coming of the peddle the clutch has a chance to engage better...

DSG

But no it really doesn't feel like clutch slip anyway.

Thanks for trying though.

TonyZ

[VWellsy]

ok Ill have a stab
needs logging with VCDS
Id also be seeing if the symptom happens in stock REVO mode
you can check throttle angle (2 sensors in the pedal) to confirm/rule out the pedal itself

I would be thinking
a) REVO settings if it happens in mapped but not stock mode
b) pedal or maybe something like a leaking fuel injector if it happens in stock mode too

other thing to consider is that its nothing to do with the engine(which is running fine)
but the 'effect 'you feel is knackered engine mounts allowing excessive rock ???

Ta John o, that seems like some good suggestions there, i'll check with the REVO setting over the weekend as I've not had chance to get to the garage yet and get it looked at. I also really want to get it logged to see what that throws up!!!

Would knacked engine mounts really have that effect? (I honestly don't know )

Also Richn83, I hear where ur coming from, and that's not a bad suggestion either - not enough air for fuel.

Along those lines I was wondering if I was running to much boost with our summer temps ( it'll even reach the mid 20's in Sunny Bournemouth  )

I'll keep you all posted and thanks for your help and ideas