Poor Mpg 2.0 TFSI..

Tfsi gone

Well-Known Member
At the end of the day. A few miles per gallon saving is nothing when compared to screwing the guts out of the TFSI engine. Depends on how old and boring you are ;)
 

TimWills28

Well-Known Member
VCDS Map User
Fitted thermostat last night, RIP my back, legs and hands. Reset DIS, now have average of 30ish mpg when crushing and 26mpg when in city :)
 

S3Alex

Rarely neutral
Gold Supporter
Good result.
We had some sensor problems with mine a while back and the mpg suddenly slumped.

Turned out the thermostat had packed in,the MAF was clogged and the lambda probe was intermittently giving bad values.
All that got fixed and the real problem was a faulty throttle body.

And the car still worked.

Anyhow it sometimes turns out that mpg changes are useful as it shows up a problem.
 

TimWills28

Well-Known Member
VCDS Map User
I've gone from an SE trim to SPORT. So didn't have DIS before, kinda looked forward to having then to find out current mpg never is steady and have to use average all the time. But yes shows if something's not running normal which is good :)
 

S3Alex

Rarely neutral
Gold Supporter
I've gone from an SE trim to SPORT. So didn't have DIS before, kinda looked forward to having then to find out current mpg never is steady and have to use average all the time. But yes shows if something's not running normal which is good :)

That's it.

I'm not too bothered about 20mpg vs 30mpg etc but I would be looking for a cause if the average drops for no good reason.
 

TomSx

Registered User
Also change your PCV. Just done mine and it's quicker and getting 5 more mpg on my run to work.
 

TimWills28

Well-Known Member
VCDS Map User
Also change your PCV. Just done mine and it's quicker and getting 5 more mpg on my run to work.

Was on my to do list..how could I tell if my current pcv is knackered?
 

DriverN00B

Registered User
One way is with engine running remove the dipstick, if it starts running lumpy and sound like it's going to stall, the PCV is fine.

If the engines still running smooth, its knackered.
 

TimWills28

Well-Known Member
VCDS Map User
One way is with engine running remove the dipstick, if it starts running lumpy and sound like it's going to stall, the PCV is fine.

If the engines still running smooth, its knackered.

Will check this tonight before I leave to go home...
 

RosscoJr

Registered User
I was told another trick with the PCV to remove the oil cap while running, if there is suction its gone....but that cant be right of course there will be a vacuum. I can only imagine the dip stick is going to be the same?
 

TimWills28

Well-Known Member
VCDS Map User
One way is with engine running remove the dipstick, if it starts running lumpy and sound like it's going to stall, the PCV is fine.

If the engines still running smooth, its knackered.

Done this morning, pulled out dipstick and Engine running rough which means it is fine?
 

Mario8P

Registered User

TimWills28

Well-Known Member
VCDS Map User

Spatula

A4 B6
Other way round I think. If engine starts running lumpy when you remove the oil cap, usually a sign your PCV is knackered. Just changed mine today. £38 from Audi parts and 10 minute job.

EDIT: There shouldn't be a strong vacuum when trying to remove the cap.
 

TimWills28

Well-Known Member
VCDS Map User
Other way round I think. If engine starts running lumpy when you remove the oil cap, usually a sign your PCV is knackered. Just changed mine today. £38 from Audi parts and 10 minute job.

EDIT: There shouldn't be a strong vacuum when trying to remove the cap.

Could not remove oil cap only dipstick. It was too tight ... Hmm ...
 

Smirky

Registered User
Your oil cap was to tight? Never heard that before
 

TimWills28

Well-Known Member
VCDS Map User
It was okay not too tight it was tight on with engine off as well. Did it this evening an engine ran rough...is this bad or good?
 

Spatula

A4 B6
I literally did mine yesterday. Symptoms were slight whining/squealing noise like a belt was on its way out, eratic revs on idle and when changing gear would sometimes jump up when I put clutch in, engine management warning light finally came one. These symptoms on became apparent when the engine was at temp.
Got it on Vag-com and came up with system too lean. Checked for air leaks, nothing. Tried the old tested way or removing oil filler and there was a huge vacuum and it was really hard to undo, then once it was off idle went to pot and almost stalled.
Replaced PCV (10 min job) and all problems were fixed. Oil filler now has barely any vacuum, if any.
 

TimWills28

Well-Known Member
VCDS Map User
I literally did mine yesterday. Symptoms were slight whining/squealing noise like a belt was on its way out, eratic revs on idle and when changing gear would sometimes jump up when I put clutch in, engine management warning light finally came one. These symptoms on became apparent when the engine was at temp.
Got it on Vag-com and came up with system too lean. Checked for air leaks, nothing. Tried the old tested way or removing oil filler and there was a huge vacuum and it was really hard to undo, then once it was off idle went to pot and almost stalled.
Replaced PCV (10 min job) and all problems were fixed. Oil filler now has barely any vacuum, if any.

Car idles fine and no codes in dash so I don't think any symptoms are present and my mpg has gone up since replacing thermostat
 
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