Bad mpg, hissing noise, lacking power

[magic123]

hey guys ive got a 2.0T audi a3 quattro on a 56 plate currently on 43k mileage, its getting i think pretty bad mpg, i drive 12miles to work one way and about 10miles of this is on a A road so can sit at a constant 70mph, whatever i do or however i drive i get 320 to a tank, it says 21.3mpg and on a run at 65mph for about 70miles i was only getting around 24mpg, when i put the clutch down to change gear i get like a twshhh noise almost like a dump valve twshh noise but not as agressive or loud, sounds like its coming from behind my steering wheel almost, it can lack power too afew tiems put my foot down and theres hardly any power, even if its at around 3/4k of revs, feels like im in a 1.0 sometimes, ive been told to check the PCV valves, DValve/divert valve and a customer (i work in insurance) said about the 02 sensor, any ideas or suggestions very welcome

 

[TDI140]

Boost leak mate im having mine sorted tomorrow on my 2.0tdi the intake hose which connects onto the inlet of the turbo has perished and melted away due to using a jubilee clamp to hold it on, i found out with having a boost leak test done so i recommend finding someone with a smoke machine to test the hoses for splits/leaks

 

[magic123]

Boost leak mate im having mine sorted tomorrow on my 2.0tdi the intake hose which connects onto the inlet of the turbo has perished and melted away due to using a jubilee clamp to hold it on, i found out with having a boost leak test done so i recommend finding someone with a smoke machine to test the hoses for splits/leaks

cheers, mines the petrol but sure its all a similar thing, my mate works for ford whos gonna plug it in in afew weeks and see what happens but nice to know what to look out for cheers

 

[TDI140]

Sounds like boost leak i know the tfsi engines have a standard dump valve but i do t think it should make a noise like your describing, i say take it to get smoke test done to see what hoses are leaking it only costs £10 so worth it ill upload a pic of the part later on today to show you what was wrong with mine

 

[magic123]

CHEERS IS THERE ANYWAY TO SEE PHYSICALLY? SORRY FORCAPS ON MOB N WNT LET ME REMOVE

 

[Ash187]

you could take the under tray off the car and pop your head under to see if there is any oil on the end of any boost pipes.

 

[magic123]

haha sounds hard! where would i do that?! plus i am a girl! lol

 

[magic123]

any easy or quick way to check that TDI?

 

[MrLapou]

If you are clueless and unable to to basic investigation; for safety reasons, take it to a specialist garage.
Sounds like a boost hose / connection has given way.

 

[TDI140]

Doesnt matter if your a girl get your hands dirty lol girls working on cars oooooh lol, just need to find a garage that does boost leak tests,
look at this picture the hose on the left is old and the right is the new one and die to that not being on my turbo compressor housing properly as soon as i put new one on turbo blew up
View attachment 14688

 

[magic123]

Doesnt matter if your a girl get your hands dirty lol girls working on cars oooooh lol, just need to find a garage that does boost leak tests,
look at this picture the hose on the left is old and the right is the new one and die to that not being on my turbo compressor housing properly as soon as i put new one on turbo blew up
View attachment 14688

oh wow definately a change you can see! i dont mind working on cars, ive got a horse so used to being or getting messey lol i meant how am i meant to get under it at home!

 

[TDI140]

You need to jack it up and get couple axle stands underneath it so its safe then remove your under tray and check all boost hoses to see if they are secure also check if they are split so best to take them off and check also clean them as they may have oil in them, not sure how many hoses on the TFSI engine but check them for splits and wear and tear if you see any damage on hoses order a new hose the standard hoses are a bit weak so i ordered FORGE ones from forgemotorsport.co.uk and replaced all the hoses for silicone ones but if you dont want to soend alot them hust go for standard ones,
thats it really and whilst your under the car i say check the turbo hoses make sure they are all connected to the turbo as the one i have shown in the inage above caised my turbo to overheat and when the new hose was put on the turbo popped within seconds of being on the road :-(