[Lioness]

I have got a 2013 HYUNDAI I30 ACTIVE BLUE DRIVE CRDI (109), it has 20,000 miles on the clock. I have filled it up once since I have had it and only got 365 miles out of the tank.

I am doing round town driving. I knew it was not going to be as expected, but I didn't think it would be that bad. My MPG was about 33.

Is something seriously wrong 

[Doggie 1]

Hello and welcome to the forum.

The only way to accurately test the fuel consumption is to brim the tank and record the kms & litres, then do the same next time.

What sort of driving do you do? Is it mainly stop/start or highway?

Is it a manual or auto?

I have a 2012 diesel manual and regularly get 1000 kms out of a tank with a mix of urban & extra-urban driving, so you need to measure and record exactly what is happening.

[asathorny]

MMMmm doesn't sound too good that...  As said, you'd need to do a proper test to be sure.  Can't really trust the on-board computer to be exact.

Let us know when you tested it fully, also be aware that diesel fuel efficiency tends to improve with age 

[Lioness]

Hi,

I have brimmed the tank and reset the mpg.

It is a manual and I do mainly start-stop driving, which would be very "urban" driving.

Even when I brimmed it the total miles for the tank was showing about 400 and something miles.

I thought considering the car has done almost 20,000 miles, it would be on point

[Doggie 1]

Give it a couple of goes and see how it averages out.
Maybe some other members will have other suggestions.

[Lioness]

I hope so, because I feel to contact the dealer that I bought the car from.

[AlanHo]

You need to take care that you really did brim the tank fully. Diesel foams as it flows into the tank and will take a little time to lose all the bubbles. When I brim the tank it takes me several minutes. The diesel will keep clicking the pump off and you need to wait for about 20 seconds before you can add more fuel. The tank is not accurately brimmed until you are able to see the surface of fuel static in the filler pipe such that if you added more it would over-flow.

Now make a note of the odometer (speedo) mileage and use the car until the warning light comes on. Now refuel it to the brim again (you will probably get about 55 litres or more into the tank). Make a note of the odometer reading and the litres added.

You can then do a manual calculation of the true mpg by dividing the distance between fills by the litres added and then multiply by 3.786 to give mpg.

I would expect you to be getting about 50 mpg during short distance town driving. However - read on.

Your car is fitted with a diesel particulate filter (DPF) in the exhaust pipe which is a legal requirement for new diesel vehicles in Europe. It is therefore not suitable for being used solely on short start/stop journeys.  The DPF filters the exhaust to remove carbon particles being emitted. This carbon builds up in the filter and has to be removed when the filter is full. This is done by extra fuel being injected into the engine to raise the exhaust temperature to about 600 degrees C and burn away the carbon deposits - a process called regeneration. The regeneration cycle takes about 20 minutes or 20 miles of fast driving with the engine revs above 2000 rpm.  My car regenerates about every 250 miles - but I do regular fast trips exceeding 30 minutes for about half the time. The other half being town driving.

If you never take the car on a long run regularly the DPF will have to try to regenerate more often to burn the carbon deposit off the DPF. If you are only using the car for short runs all the time it could be that the regeneration cycle is being activated almost constantly which would then result in poor economy. (When you stop the car in traffic does the engine stop - or are you getting a message in the instrument panel telling you that auto stop is deactivated. This message will appear when the DPF is regenerating which will give you an indication of how often it is occurring).

You need to look out for a warning light flashing in the instruments which indicates that regeneration of the DPF has failed and you need to take the car on a long fast trip to enable it to happen. This takes roughly 20 miles or 20 minutes.  If it is still flashing after this trip take the car immediately to the dealers for urgent attention.  If you fail to do this the cost of a replacement DPF is about £1500.

I don't intend to frighten you - but you need to be aware that your suspected poor economy may be a direct result of not ever using the car on longer trips that are necessary to give the DPF a chance of regenerating.

A sensible dealer will ask potential buyers what type of use the car will have so they can advise whether a diesel will be suitable.


Do please let us know how you get on.

[eye30]

Don't forget the car's ecu will have "remembered" the previous owner/drivers driving style.

It may be worth clearing the ecu's memory.
You do this by disconnecting the battery for at least 30 minutes.

Start again and see whether mpg improves.

[Asterix]

Hi Lioness

 

As said, the diesel is not suitable for short trips only.

I have a daily commute of 2x25 km. If I did any less, I would buy a petrol due to the DPF on the diesel.

Keep us posted on the consumption...

[Phil №❶]

Are you using the bluedrive option when driving. 

[Dazzler]

I have a daily commute of 2x25 km. If I did any less, I would buy a petrol due to the DPF on the diesel.

I doubt it, what would you use to pull the caravan? 

[beerman]

It also pays to know what constitutes 'urban' from http://www.dft.gov.uk/vca/fcb/faqs-fuel-consumptio.asp


    Urban Cycle
    The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).
   
The urban test outlined above definitely is not day to day stop start driving, hence there is no chance that you will achieve the same economy. That's before you take into account driving style, extra weight in the vehicle, tyre pressure, climate control use and a million other things that affect fuel economy.

[Asterix]

I have a daily commute of 2x25 km. If I did any less, I would buy a petrol due to the DPF on the diesel.

I doubt it, what would you use to pull the caravan? 

I would very much like this to be my Next car:

Skoda Octavia 1,4 TSI 140 HP/250 Nm

It's a petrol turbo with same torque as my i30 CRDi but the Nm's are present over a wider rev area; 1500-3500 revs. and there's more HP. The Price is about the same as the i30.

I can't get the i30 with a petrol turbo, so that's no option.

[Dazzler]

I quite like Skoda Octavia.. We rented one in Adelaide 1.8 TSi and it was very nice.

My friend got a 1.8 TSi and increased KWs to 245 from 118 (but not sure of the NM before and after) He spent over 10K on mods!

[AlanHo]

We did a return journey to Cheltenham this morning via the M42 and M5 motorways. It was a round trip of 119 miles with 2 miles urban near our home and 3 miles urban in Cheltenham.

It was a cold day and the car temperature gauge stayed at 3 degrees C the whole time.  I cruised the motorway at 55 to 60 mph.

I got my wife to record the odometer reading and trip average economy at certain intervals from which I have calculated the economy as follows :-

1st 14 miles before engine reached its normal temperature (5 bars) 56.2 mpg (5.02 l/100k)

Next 45 miles to destination                                                          68.6 mpg (4.12 l/100k)

Immediately after starting the return journey the DPF started to regenerate just as we reached the ramp back onto the M5.

18 miles during DPF regeneration on the M5                                  46.8 mpg (6.04 l/100k)

Then 42 miles back home                                                             69.2 mpg (4.08 l/100k)

Overall economy for the 119 miles                                               63.7 mpg (4.43 l/100k)

 (Overall would have been about 67.1 mpg (4.21 l/100k) if the DPF had not regenerated)

With my mix of roughly 50% urban and 50% motorway driving the car has averaged 52.3 mpg (5.4 l/100k) over its first 6500 miles.

Assuming it usually achieves 63.7 mpg on motorways I calculate that it must be averaging only 42.8 mpg (6.6 l/100k) during town driving.

[Dazzler]

Thanks Alan (that was interesting) 

[Phil №❶]

  Mrs Ho. 

[Tourer_Guy]

We did a return journey to Cheltenham this morning via the M42 and M5 motorways. It was a round trip of 119 miles with 2 miles urban near our home and 3 miles urban in Cheltenham.

It was a cold day and the car temperature gauge stayed at 3 degrees C the whole time.  I cruised the motorway at 55 to 60 mph.

I got my wife to record the odometer reading and trip average economy at certain intervals from which I have calculated the economy as follows :-

1st 14 miles before engine reached its normal temperature (5 bars) 56.2 mpg (5.02 l/100k)

Next 45 miles to destination                                                          68.6 mpg (4.12 l/100k)

Immediately after starting the return journey the DPF started to regenerate just as we reached the ramp back onto the M5.

18 miles during DPF regeneration on the M5                                  46.8 mpg (6.04 l/100k)

Then 42 miles back home                                                             69.2 mpg (4.08 l/100k)

Overall economy for the 119 miles                                               63.7 mpg (4.43 l/100k)

 (Overall would have been about 67.1 mpg (4.21 l/100k) if the DPF had not regenerated)

With my mix of roughly 50% urban and 50% motorway driving the car has averaged 52.3 mpg (5.4 l/100k) over its first 6500 miles.

Assuming it usually achieves 63.7 mpg on motorways I calculate that it must be averaging only 42.8 mpg (6.6 l/100k) during town driving.

Very good numbers indeed.

Does the economy decrease much if you run along at say 65mph?

[AlanHo]

Very good numbers indeed.

Does the economy decrease much if you run along at say 65mph?

Yes, previous tests with my last two i30's  - both GD diesels - indicated that on a long round trip of more than 300 miles, mainly on the M42 and M5 motorways, cruising at about 65 mph produces economy of around 58 mpg overall - especially because a DPF regeneration normally happens in this distance.

[ttc]

I have an app on my phone called Fuel log, it gives me more accurate figures than the car does.

[AlanHo]

I have an app on my phone called Fuel log, it gives me more accurate figures than the car does.

How does that work.

[ttc]

you install it, then you fill in the details for each fill up.
it asks for km, L, price per L, and it works out how much it costs, and it keeps records for you.
You can add in services and stuff as well, for example I logged the accent for 15 months(447 days it says), Best fuel consumption was 4.5, average was 5.29, worse was 6.4l per 100km
Avg cost per km was ten cents, $3.9 per day, 27.32 per week, 118.73 per month, and 1424.59 per year.
I did 16,650km and used 916.7 litres.
Filled up 26 times and spent $1401.27 on diesel.
Fuel was on average 1.53 per litre..

There's more stuff I couldn't be bothered to write it all..

[AlanHo]

Thanks for that - it looks interesting. I presume you have to brim the tank on every fill in order for the economy calculation for each tank to be correct.

There seems to be a discrepancy between the overall average given by the App at 5.29 and a manual calculation based on total fuel and distance.

I make it 5.51 litres/100km using the total fuel and distances you have quoted.

[eye30]

Of course you are all assuming the ode reading in correct and not either over or understating.

[ttc]

There is an anomaly in the graphs from where I had to guess from the diesel algae episode, so that probably threw it out.
I do agree that does add up more to your figures than theirs though

[AlanHo]

Of course you are all assuming the ode reading in correct and not either over or understating.

I don't make that assumption with my car - as posted here previously - I have taken the trouble to check it against my sat-nav and the kilometre posts over a long distance on the motorway.

The odo in my previous 2012 GD i30 hatch read 1.8% under
The odo in my present 2013 GD i30 Tourer reads 1.13% under.

[Just Rick]

I'm with you Alan,I constantly check mine against the sat nav Bruce is 2% under and Cyril is 3 % under.
As stated,400 miles is 640 K's for us,this could be possible if you are continually doing stop start and a lot of idling time and very short runs

[Doggie 1]

Of course you are all assuming the ode reading in correct and not either over or understating.

I don't make that assumption with my car - as posted here previously - I have taken the trouble to check it against my sat-nav and the kilometre posts over a long distance on the motorway.

The odo in my previous 2012 GD i30 hatch read 1.8% under
The odo in my present 2013 GD i30 Tourer reads 1.13% under.

But that is presuming the satnav and the km posts are correct.

[Phil №❶]

Pretty sure the satnav tracking in 3 axes to multiple decimal places using atomic clocks for timing, would be fairly accurate.

Km posts inserted by DOT workers, I'm not so sure. 

[AlanHo]

We travel down to Cornwall every couple of months or so, which takes us along the M42, M5 and A38 or A30 depending on final destination. I have measured the distance three separate times between kilometre boards near to junctions J4a and J31 on the M5. I am satisfied that the motorway distance boards are accurate because I  checked this with a friend who was project construction manager on a long section of the M42 who confirmed they use GPS to position them to within plus/minus 5 metres.

According to the Kilometre posts the distance is 233 Km - my sat nav measured 233.1, 232.8 and 234.1 kms respectively. An average of 233.3 km which is a difference of 0.12%. The car odo measures in miles which converted to kms gave distances of 230.2, 229.7 and 230.5 kms respectively - an average of 230.1 kms.

Hence the difference between the car odo and the km boards is 1.13% slow and with the sat nav 1.14% slow.