Any ideas. Temp low miles per gallon

[andy187781]

Engine temps anything to do with low mpg. See pic of temp and average mpg 

[penguin17]

Does the engine temp increase when you're stationary or moving? 

 

EDIT: My initial thought is the temp sensor/thermostat.  Often a problem on VW Groups cars of this vintage and when the cars where new/still in warranty, VW group replaced the units FOC as they knew they weren't fit for purpose (and yes, if the temperature readings are incorrect then a side effect could be poor economy)

Edited 19 December, 2019 by penguin17

[Liverpool-Lad]

As above - common issue.  Advise buying genuine parts or you may be doing the job again before long :)

[andy187781]

Yeah I'll replace them both ASAP..also it does warm up slowly when idle. One other thing. I used a turbo cleaner additive last fill up. Seemed to work..until earlier on where it's gone back to being low powered when driven for a while..don't know if it's because this time filling up I added an injector cleaner also .wasn't even a long drive? 

[mac11irl]

CTS not heating up fully makes engine over fuel.

Also, in cold weather fuel is also more dense so you use more anyway, and different companies add "winter mix" additives to help prevent freezing etc in very cold weather which also going to drop the mpg.  Add all the above together and suddenly...

 

Separately...

If the turbo is full o' gunge, look for the mr muscle job thread and give a read. Most fuel additives do very little for engine cleaning tbh...

[KenONeill]

In which context, a fuel additive in a VAG TDi these days is injected to the combustion chambers, so can't clean the compressor and will have been burnt before it gets to the exhaust port. It might still clean the injectors and/or combustion chambers, but not the bits that really get gunged up.

Edited 19 December, 2019 by KenONeill

[Ootohere]

Nonsense on the Winter Spec Diesel IMO & IME and that is over years of watching MPG's.

If the weather is the same in November as in September a diesel vehicle goes as far then as it did before.

Actually from the first tank of Winter Diesel i put in each winter for the last 2 winters my range per tank went up from 630 miles to 730 miles.

But then that was the same trips and the weather was colder and TDI's love cool air when the engine is up to temp so on longer journeys.

 

http://omv.com/en/blog/winter-diesel-diesel-that-doesnt-get-cold

 

OT, 

But UK winter spec petrol and super unleaded that comes in sometimes from Europe can be lovely stuff with the Min octane of 95, 

or Super 97 or 99 ron Minimum.

It can be as good as Continental 100+ winter fuel, because sometimes it is, and sometimes past March that is still coming into the UK.

Edited 19 December, 2019 by Roottootemoot

[andy187781]

seriously thinking of just moving on to a different car TBH. i can see it being a bit of a money pit. Cars are i know, but .....I'll tinker and tweak here and there. if no joy i'll move on. it got quite a few issues. Mostly age related.  Rev above 4000rpm it stalls usually, driver door switch not working(No Lights on warning or light coming on inside), lots of minute scratches on the windscreen, Reverse Parking beep is almost inaudible but works. Speedo sometimes jumps a bit on idle. Rear wiper works for five mins and stops. Its getting a little bit noisy over bumps and the Liverpool roads not helping

[mac11irl]

Get a new cts and it will make a big difference.

 

Unplug the maf and see if the stall at 4k is cured.. it mightnt, but it will rule it out and its free...