Octavia 2.0 TDI Increased Fuel consumption 20% higher, 6 speed manual

[Hanifk]

I have a 2015 Octavia Estate with 200,000 Kms ( 120,000 Miles).  Engine code is CKFC. 150Bhp Manual 6 speed gearbox 

Bought the car used in Germany with 90,000 kms. I have driven 110,000 Kms in 5 years.  

The car is used on local roads for 50% of the journeys between villages (50-60Km/h speeds) and on Highways at 100 to 130Km/h speeds for the remainder of the journeys. Usually without any load and only returning back with grocery shopping.. something we have done for 5 years.

This has been the norm for the past 5 years with exceptions of touring journeys across the continent once a year with 3,000 to 5,000 Kms per trip. 

Using manual calculations with an established driving pattern and known fuel consumption, I have noticed an increase in the fuel consumption calculated at 20% higher in the past few months. Using the same fuel stations as before, regularly serviced before the due mileage with recommended oil and all filters, fuel filter replaced every 2 services. 

Use injector cleaner on average once a year. 

Tyres are maintained and replaced with the same Michelin model each time with pressures checked regularly, also has pressure sensors so get warnings in case it drops, changes made for winter and summer tyres with 2 sets of alloy wheels to have stability in all seasons. 

Having no changes to the driving pattern and annal maintenance habits I cannot understand the increase in fuel consumption? 

Due to have a clutch change resulting from an increased rattle from the DMF.. Clutch is fine and not slipping, otherwise nothing unusual which I am able to think about effecting fuel.. 

 

Any suggestion which I can look into and review other options which need further investigation. 

Much appreciate any advice. 

Thanks Hanif

[Ootohere]

Re your fuel station and the same fuel.  Do you not get Winter fuel in Italy each Winter, which is not the same as Summer diesel.  It will be the same energy for the money and then the same each winter you have been running the car. 

 

I assume that you check your air filter and know you are running a fresh / clean one all year.

[Hanifk]

No we don't get a winter fuel as the temperatures don't go too low unlike Scandinavia.

Yes the air filter is cleaned mid services and replaced each year. 

 

[KenONeill]

3 hours ago, Hanifk said:

Use injector cleaner on average once a year

Why? No, really why? Why are you wasting money on snake oil and then complaining about fuel economy?

[Hanifk]

24 minutes ago, KenONeill said:

Why? No, really why? Why are you wasting money on snake oil and then complaining about fuel economy?

Using Injector cleaner / snake oil as you describe it, has not effected my fuel consumption in the last 5 years. 

it is recently that I have seen a 20% drop in fuel economy. These 2 are not correlated if you read my full description. 

 

[Cap44]

Snake oil.   When last in Spain in our Fait 2-8 Motorhome A can of Wynn's Injector Cleaner every 3rd tank paid for itself in increased fuel economy with the add on off certainly having  more power on long hills.     

[fr1nklyn]

I don't think your DPF is clogged by your type of journeys, but on 200k km it certainly does regenerate more often which increases the fuel consumption with ~0,5-1L/100km. Again this isn't what you're experience as this isn't 20% consumption increase.

 

I believe you know what "Italian tune up" means, you can try doing it  

[Hanifk]

4 hours ago, fr1nklyn said:

 

 

I believe you know what "Italian tune up" means, you can try doing it  

I agree my DPF is not clogged up as I have noticed it on times when I have driven a lot at lower speeds and shorter journeys the car has done the Regen and its noticeably different to what I am experiencing consistently now. 

 

Regarding the 'Italian tune up' I have done this in the past inadvertently, but recently this has not been done.. 

I guess I should make a conscious effort on this to see if it works.  

Thanks 

 

 

 

[Hanifk]

On 05/05/2023 at 06:12, fr1nklyn said:

I don't think your DPF is clogged by your type of journeys, but on 200k km it certainly does regenerate more often which increases the fuel consumption with ~0,5-1L/100km. Again this isn't what you're experience as this isn't 20% consumption increase.

 

I believe you know what "Italian tune up" means, you can try doing it  

 

 

Update:

The car has had a "tune up"

Some cobwebs were cleared. could not drive it to its full potential as I have a weak DMF, just managed to get the complete LUK kit ordered today due to stock issues. 

Once its fitted I can give it a thorough tune. 

 

I had intended to clean the throttle body as there are many indications on my mileage that this does get clogged. Looking everywhere under the bonnet for the same pipes etc as I have seen online in Youtube videos. 

Only to find a completely different system is installed, which is a water cooled intake system. OEM Valeo system. Photo attached. 
I have seen very few references to this part and issues, except when there has been an internal water leak. it also seems to be fitted on other engine types as there are few references to CKFC engine code I have. 

Due to the complex cooling and air system inside I am somewhat hesitant to open it for a clean out, or to use a cleaning solution to spray inside. 

I am sure its needed as it seems to struggle 'breathing properly'.

Until I can get more supporting feedback from experienced drivers who have this same intercooler I will be cautious. A replacement part only price is more expensive than a complete clutch DMF system fitted. 

 

 

 

 

 

 

[J.R.]

I was going to suggest the throttle valve being crudded up.

 

Yes that is very different and may not suffer the same fate, does it even have a throttle butterfly in there and is one of the pipe stubs for the EGR gases?

 

You could try looking inside with an USB endoscope.

[SuperbTWM]

As has been disussed previously, this engine has 2 EGR systems high and low pressure  complete with control valves and coolers for each, it still has the same throttle butterfly but with an additional throttle butterfly in the exhaust as well for added backpressure for even more EGR goodness, this might be worth a check to make sure is not suck but im sure the car would let you know via the EML.

 

The majority of the EGR flow comes from post DPF so intake should be relatively clean compared with pre 2015 Euro 5 variants. I agree a cheap endoscope would be handy to have a look inside and up at the cooler, would be interesting to see how much build up there is.

 

I am sceptical that this sort of build up would cause any sudden economy issues though, it would probably be much more gradual and not noticeable. Have you scanned for fault codes recently?

 

Have you jacked up each corner to make sure the brakes are not binding or felt for excess heat after a long drive?

 

 

Edited 13 June, 2023 by SuperbTWM
terrible spelling

[Hanifk]

10 hours ago, SuperbTWM said:

As has been disussed previously, this engine has 2 EGR systems high and low pressure  complete with control valves and coolers for each, it still has the same throttle butterfly but with an additional throttle butterfly in the exhaust as well for added backpressure for even more EGR goodness, this might be worth a check to make sure is not suck but im sure the car would let you know via the EML.

 

The majority of the EGR flow comes from post DPF so intake should be relatively clean compared with pre 2015 Euro 5 variants. I agree a cheap endoscope would be handy to have a look inside and up at the cooler, would be interesting to see how much build up there is.

 

I am sceptical that this sort of build up would cause any sudden economy issues though, it would probably be much more gradual and not noticeable. Have you scanned for fault codes recently?

 

Have you jacked up each corner to make sure the brakes are not binding or felt for excess heat after a long drive?

 

 

HI, 

 

Thanks for all the tips, I had seen these descriptions you mentioned of  2 EGR systems but no images which made it hard for me to find my way around the engine bay when All the images and videos were for the more common single type. 

I have no error codes showing and last summer the brake disks were changed with new pads along with wheel bearings and 18 months ago all the front suspension bushings, ball joints, track rod ends anti roll bar rubbers were all replaced. We have very bad roads so this happens every 3 years on average. New springs and shocks were replaced 20 months ago.

I regularly check the brakes when we change from winter to summer tyres, I have 2 sets of alloys which makes it easier and I am able to check the condition of the wheel area, brakes and suspension in Mid April and Mid November.  There is no excessive wear on the pads or disks, they are in excellent condition.
These are all fine, which is why my research was in other areas. 

 

My location is in a small village about 25Kms from the nearest small town and 35kms from a decent hospital, It is important to me to have the car in optimal condition at all times. With family back in the UK we have sadly had to make an emergency drive to the UK. Knowing the car is optimal condition gives me the confidence that I can go anywhere at the drop of a hat. 

 

I will look into getting a endoscope to see what can be discovered and will try to get images to control the situation. 

I had seen in another post yesterday where they had a leak in the intercooler, there was a build up of soot however it was congealed with the water and coolant leak, so the actual condition without the leak could not be ascertained.

 

Will keep posting updates as I make progress. 

 

Ah just had a notification as I type that my  DMF clutch kit is not in stock and even though it was paid for its cancelled.. Back to square 1. 

 

This is a year of poor luck with getting car parts for me. 

 

[SuperbTWM]

This gives a fairly good overview of all the main control and emissions systems:

 

https://pics.tdiclub.com/data/517/820433_EA288.pdf