No Boost....

[Andy_GunMetalGolf]

So I'm on Anglesey in some pretty awful weather and on a back lane I came up against a flooded Road. It wasn't very deep and I went slow and steady but I did briefly get splash water upto bonnet height but only like hitting a puddle. Since then my car seems to lack boost and I'd say feels like it's a standard 2.0L. (mk5 gti, fsi mapped to 280bhp).

Can anyone offer a non mechanically minded owner some checks or things to look for? Can you actually see anything from the engine bay? It drove OK and got me back to my hotel but I still have 120 miles to drive home tomorrow. If there is a leak or split pipe is it still OK to drive if it feels like it's driving okay??

Cheers,

Andy

[muff1991]

if the car hasn't corrected itself yet.. then take the terminals off the battery and leave the car to stand dead for half an hour or more. this will reset the ECU and i'd pretty confidently say it will sort the car.

I had a similar thing way back on a different car.

[Andy_GunMetalGolf]

Thanks for the reply Muff i'll have a go at that. So the car went to my local garage where they couldn't find any fault codes and said the car was running fine. So i went and picked it up and it ran perfectly.... untill last night.

So last night i came back up the m6 and once again, turbo seemed to cut off, hardly any acceleration or power, but still drove and happily sat doing 70mph.

Pulled off the m6 down to a roundabout and it then wouldn't accelerate at all. Engine still running but the accelerator pedal would go flat to the floor and not rev the engine at all.

Hazards on...... turned it off thinking it was an RAC job. Turned it back on..... brilliant everything back to normal?!! Got home on full boost. Very strange.

So i'm going to say an electrical fault any idea of any sensors or valves that would cause this but not through up any dash or warning lights???

[The Red Warrior]

Just throwing this out there.... could it be the electronic part of the actual accelerator pedal. If that was worn or faulty then the car wouldn’t recognise when your putting your foot down (hence the no acceleration bit) and won’t allow as much boost from the turbo as it thinks your foot isn’t very far down on the accelerator pedal (ie driving like a nana).

I have heard of accelerator pedals going bad before on mk5 GTI.

[Dan_FR]

It's not the throttle pedal, it's a form of 'limp home' mode as the ECU is seeing something it isn't happy with. Car needs a fault code scan and datalogging

[Andy_GunMetalGolf]

Is the fault logger and datalogging something i can buy and do myself. Can someone point on what to buy. I'm planning on keeping the car, so happy to invest in the tools.

[pudding]

VCDS is still the most useful diagnostic tool for VW/Audi cars, but not the cheapest, and not the most modern of interfaces....... but it's solid and reliable, which is more important than pretty pictures on a tablet.

[ronaldRop]

I used the bottom bigger? nipple on the WG...think it matters?
 
and where can you get a filter...because my boost gauge flutters and its annoying.