Some help and advice please. Octavia vrs, 2019 petrol, 15,000 miles.

About 500 miles ago, the fuel consumption increased from average 38/39 to 31/32. Exactly the same journeys and driving style (I spend a lot of time doing the same journeys having to drive at 60 mph in motorway roadworks and driving also on rural roads). Accurately calculated several times by filling the tank and low mpg is the same as the electronic fuel readout.

 

Just been serviced by dealer and nothing wrong found. No loss of power noticeable or strange noises.

 

Any ideas what it could be or suggestions of what to look for. All advice gratefully received and thanks in advance.

Whatever is causing the issue is putting additional pressure on the engine.

 

Couple of things to look at:

 

1) check the brakes - are any of the brakes hot when you arrive your destination (ie dragging brake?)

2) A dodgy batch of fuel?

3) Tempertature makes a difference - but it should be no more than 4-5mpg (anything colder than 7C will make the car run richer)

4) Do some basic checks - make sure that oil level / coolant are correct.

5) Tyres - my dealer has an annoying habit of lowering the pressure back to standard pressures (which are too soft).  Check your tyre pressures.

 

See this thread

@purrlyne Welcome to the forum.

 

Be sure to ask on the phone or in person and also by email if the Tech carried out a Software Update on your car without you being told that it had been done.

Thanks for the suggestions

I will look at the brakes when I can. I have filled up with fuel from different garages to make sure it wasn't one dodgy batch.

 I got the car serviced yesterday to see if there was anything wrong and they found nothing, so timing, mixture, tyres, coolant all ok. If they did a software update it made no difference, because it is still using 25-30% more fuel than 500 miles ago.

1 hour ago, varaderoguy said:

Whatever is causing the issue is putting additional pressure on the engine.

 

Couple of things to look at:

 

1) check the brakes - are any of the brakes hot when you arrive your destination (ie dragging brake?)

2) A dodgy batch of fuel?

3) Tempertature makes a difference - but it should be no more than 4-5mpg (anything colder than 7C will make the car run richer)

4) Do some basic checks - make sure that oil level / coolant are correct.

5) Tyres - my dealer has an annoying habit of lowering the pressure back to standard pressures (which are too soft).  Check your tyre pressures.

 

 

?

Do you run it on 95 ron unleaded or 97 or 99 Super Unleaded?

 

It is still Winter Spec Petrol on sale in the UK until the end of March but that should make no difference if that is what you have been using since the end of October.

I have filled up with both types of fuel to see if it made any difference. 97 RON might be giving 1 to 2 mpg more, but no significant difference.

 

Brakes binding are all I have left unless someone has got any other ideas, but the dealer should have seen that when servicing the car.

Visual inspections are not necessarily going to pick up on binding brakes.

Maybe at Skoda Main Dealers they will be advising 80% wear on brakes and need for new discs and pads.

?

Did you pay for the brakes to be serviced, if not then maybe they need doing.

Thanks for the idea, but the car has only done 15000 miles and the dealer said the brakes were 20% worn. As this problem is only 500 miles old, the brakes could be binding and not yet worn.

 

I haven't got any other ideas as to what it might be.

Just a wild crazy idea.  But maybe it is the GPF and it wants to get it's self clean.

That is if your mileage and use has been lower with shorter trips.

 

I do mean GPF and not DPF. 

It's an idea and I will try running it at high revs to see if it makes any difference, although they are not supposed to need cleaning the way that DPFs do. Thanks for the suggestion.

Look in the Air Box and see that the Air Filter is clean.

That was likely not done at the service.

 

GPF's  are not supposed to need any actions by the driver, and what is actually the facts needs checking really.  

http://briskoda.net/forums/topic/476488-octavia-vrs-245-gpfopf

http://briskoda.net/forums/topic/466684-20-tsi-190-gpf-regeneration

http://briskoda.net/forums/topic/479195-car-bahaving-strangely

 

 

Read VW's advice on gpf's.

 

http://briskoda.net/forums/topic/456700-has-my-car-got-a-gpf

 

 

Edited 19 March, 20215 yr by e-Roottoot

Solved!! Many thanks to e-Roottoot. He suggested that the GPF could be clogged up and needed "blowing through". And indeed the increased fuel consumption was almost certainly due to the GPF. 

 

I have just driven one of my usual journeys of 54 miles. Before the fuel consumption increased the car returned 44 mpg. The last three times I have done it, the car did 31or 32 mpg.

 

Tonight I did the first 6 miles with the engine revs between 3 and 4,000 revs all the time and the rest of the journey at normal revs. Overall the car returned 42 mpg, including the inevitably lousy mpg for the first 6 miles.

 

All the information on GPFs say that they clean themselves automatically and do not suffer from the same problems as DPFs. They do not need blowing through. This may well not be true. I will make sure I give it a sympathetic thrashing every now and again to avoid this happening again.

 

Thanks again to e-Roottoot.

I'm sure e-Roottoot will appreciate the thanks. His time was not wasted as you took his advice.

 

I find increasingly that we give advice & suggestions & then hear nothing. Not even a "like".

 

If people bothered to use the search facility they would find answers to many of their queries, as the same problems keep coming up year after year.

 

Rant over

 

 

@ords Well said.

We will need to remember where this thread is so that it can get linked in the future.

 

The fuel consumption increases & the GPF issues are going to be something that will be getting many questions on this forum and others and at dealerships.

 

When the GPF's were getting introduced to all VW Group Petrol cars we were told they were not going to be a problem like DPF's, that they were totally different, were maintenance free, if needing replaced they would be cheap.

http://briskoda.net/forums/topic/473535-fitment-of-gasoline-particulate-filter-gpf-to-fabia-mk-iii

 

So we get towards 3 years on and gradually we start to find that can be true, but might not be true for all.

 

Basically VW Group need to have their Franchised Dealership Staff, and 'Factory Trained Workshop Staff, fitters, techs, master techs, workshop managers etc, and the service desk staff aware that GPF are not just there and nothing a owner / customer needs to concern themselves about.

 

Customers / Drivers can be wasting time and money to put TSI's from 2018/19 on into have checked because they are using too much fuel, just to be told there is nothing wrong.

 

Clearly there might well be 3,4,5 year old cars getting to the stage that if they were put through a retest of a WLTP / RDE the results would be very different from the vehicles the manufacturers had Certificated.

 

It might be yet another VW Emissions Scandal for the future as some cars that are so new use much more fuel than they did from new and while under warranty.

 

Owners might want to ask the cost of new GPF's fitted at Main Dealers just incase a car they have or a used car they buy will need a replacement.

 

Edited 20 March, 20215 yr by e-Roottoot

http://hypermiler.co.uk/emissions/the-gasoline-particulate-filter-faq

 

Fair comment from @ords. I did search before posting, for fuel, consumption, increase and other terms. The problem was that I didn't know that I needed to search for GPF. I suspect this will keep happening. Hopefully the conjunction of all these searchable terms in this thread will mean that people will find the answers quickly.

27 minutes ago, purrlyne said:

Fair comment from @ords. I did search before posting, for fuel, consumption, increase and other terms. The problem was that I didn't know that I needed to search for GPF. I suspect this will keep happening. Hopefully the conjunction of all these searchable terms in this thread will mean that people will find the answers quickly.

Just a general observation. Not aimed at any paricular poster.

Stumbled across this thread.

 

I didn't even know there was such a thing as a GPF! My previous car was a 14-plate 1.4Tsi Superb which I guess didn't have one anyway. Now have a 70-plate Octavia mk4 1.5Tsi which presumably does. Will keep an eye on fuel consumption which so far looks good (50-ish mpg).

 

Thank you to @e-Roottootfor sharing your expertise and to @ordsfor very valid comments about acknowledging help & searching before asking.

ive just found this topic as I have the same problem and have exhausted all other ideas. My car is back at the dealership under warranty in 2 weeks. I'll be mentioning this to them.

Ive never heard of a gpf. Thank you.