[noob]

Hello everyone,

My 2011 i30cw auto diesel has just passed its first year. I did a sum up of fuel consumption in the last year. It's about 7.85L/100KM. The figure is much (35%) higher than the official 5.8L/100KM (Combined), and slightly (9%) higher than the official 7.2L/100KM (Urban).

After that, I did a full refill and cleared the trip meter in order to see how far it can run with a full tank. When the fuel meter reached the center, it has run 290KM. It means 580KM for a full tank. Since the fuel tank's capacity is 53L, it means fuel consumption is about 9L/100KM. This is even worse than the 7.85L/100KM.

I'm lost. I've heard about other people's cars doing a lot better than mine.

Here is my situation. I'm in Melbourne. I live in Camberwell and work in Fitzroy. The main use of the car was for work, in which I drove alone. There haven't been many traffic jams. In the weekends, it has been on travels to shopping centers (regularly) and beaches/mountains (from time to time), in which 2.5 adults including me were in the car. I seldom drove in/to the CBD.

My questions:
- What do Combined mean? What does Urban mean?
- In my situation, does it count as Combined or Urban?

I had learn some green driving skills before I started to use the car. I seldom applied hard push on accelerator or brake. I tried avoiding using brake as much as possible. I don't keep unused stuffs on car. I seldom refilled up to 2/3 of the tank in order to save some weight. (I don't warm my car before driving though.) The driving style didn't seem to help the fuel consumption. Or, if it did help, it means that the real fuel consumption figure can be even worse. By the way, I'm not an experienced driver and I know little about cars. But I think I'm quite good at driving.

My questions (continued):
- Is there anything I can do to reduce fuel consumption in regarding to driving style?
- I did use air conditioner from time to time, but far from often. Can it totally explain the high fuel consumption?
- The official fuel consumption data (5.8 for Combined and 7.2 for Urban) are for single person driving without air conditioner. Right?

By the way, the car sometimes trembles when I apply accelerator and release accelerator, especially when the speed is low. I can feel some dragging resistance but the time is short. The 12-month service (and earlier services) didn't find any problem. The foreman went for a ride with me for this problem and said it's normal for auto transition cars. I'm just paranoid to suspect it a cause of the fuel consumption problem.

My ultimate questions:
- Is there anything (possibly) wrong with my car?
- What can be wrong?

Any comment will be appreciated.

Cheers,
noob

[Phil №❶]

Welcome noob,

Firstly, don't try to achieve the quoted figures on the manufacturers sticker. They are obtained in a test facility using dyno rollers and not even driving on a road. They are rubbish, for that reason. Autos do use more fuel than manuals. Ensure that your tank is filled to the top, which will require careful, slow filling to avoid smelly splash back on your hands and clothes. Diesel fuel foams, unlike petrol so wear a latex glove if you're not confident.

 If your car is fitted with the trip meter fuel functions, set it to display instantaneous fuel consumption and reset it at every tank fill. This will show you what kind of driving causes bad fuel consumption. Try to avoid that type of driving if possible. Try to avoid peak hour driving and  80-100 on the highway provides the best country economy. Hope these tips help. 

[Doggie 1]

I don't think it's too bad for an auto.
My manual used to constantly give me 6.2.
For some reason it's now down in the 5's.
But there are so many variables.
The only way to really know is to "brim" each tank full and see what you get between fills.

[Dazzler]

Hi Noob and Welcome..

Combined means a good mix of Urban (city) and Country driving.

As Phil says few cars achieve these figures and they are only for comparison purposes. Our previous manual CRDi i30 was rated at 4.7 and we could manage only 5.4 LPH (which I was still happy with)

Our current Camry Hybrid is rated at 6.0 but returns 6.3 in warmer weather and up to 6.5 LPH in winter. This is from the trip computer which in both cases is probably .1 or .2 optimistic.

You can't use half a tank to judge mileage as most cars do less miles on the the lower half of the tank (if you brim the tank to start with)

Your mileage for an auto seems ok to me too.. (a lot of other auto cars would be worse) The 4 speed in the FD (series 1) i30 is  a bit antiquated. The 6 speed in the Series 2 is  a bit more efficient 

[noob]

Thank you all for the replies.

In my understanding, Dazzler considered my situation as Urban. If that's the case, my 9%-more-than-official-data doesn't seem too bad compared to Dazzler's two examples, which are 15% and 6.7%. I'm just not so sure if driving around CBD driving is Urban. Sorry, but I'm not native English user.

I guess you all consider my fuel consumption normal. The reason I freaked out was that I saw people talking about 10xx-13xx KM a full tank and 5.x-6.x LPH (Liter Per Hundred km?) many times, though I haven't spend lots of time in this forum. Both my full tank KM figure and LPH figure are much worse. Maybe what I saw was i30 rather than i30cw? I don't know.

Here comes my simple questions:
- What's the normal/representative KM-a-full-tank figure range of an i30cw diesel?
- What's the normal/representative LPH figure range of an i30cw diesel?
(Auto preferably, but manual is still welcomed.)

Thanks.
noob

[beerman]

G'day mate

2010 I30 CW auto here.

I have never achieved 1000k from a tank in the CW. The closest I got was on a trip down south to Sydney, and cruising around the suburbs where I got 998.

I spend most of my time on the freeway at 110-120k/h and I get between 5.8 and 6.2 from it.

You will be lucky to go close to the sated figures as they are under simulated conditions on rollers so that every car tested has the same base level.

Unfortunately I have never run my car in stop go traffic for any length of time, so I am unable to assist there. But it pays to remember that if the car is stopped and the engine is going, your fuel economy when measured in l/100k will suffer.

[Ugly Mongrel]

Hello and welcome, noob. I also have an auto CW diesel.

Nearly all of my driving is in city traffic and I get between 6.9 & 7.9 litres/100 km. I filled up today with 56.7 litres with 800 km on the trip meter. As suggested by other members, you need to brim the tank right to the top of the filler pipe. The weight saving by only partially filling is minimal.

As previously posted, the distance you get from the first half of the tank is a lot more than the second half. It must have something to do with the shape of the tank.

On a recent highway trip, I filled before I left and immediately on my return. The fuel gauge was on 3/4 full and took 26.43 litres. The trip meter showed 444 km. The consumption was 5.95 lt/100km, which I thought was terrific as I was doing 110kph for a lot of the trip and over 200kms was in very heavy rain.

I wouldn't worry too much about your fuel consumption figures as I believe they are normal.

[constipated]

Noob, does your car have a trip computer.

If so try to post what your average speed per tank along with your fuel consumption figures.


Dazzler, when you said you could only ever achieve 5.4L/100km, was that with the lowest figure even on the highway?

[Dazzler]

Dazzler, when you said you could only ever achieve 5.4L/100km, was that with the lowest figure even on the highway?

It always seemed to come back to that average ...

I recall getting say 5.0 or 5.1 for short periods but couldn't maintain it (I tend to sit on 110kph by the GPS where I can)

[noob]

Thanks for the replies.

There is a trip computer, though I barely used it. And I just found out that it might be broken. According to the PDF manual I downloaded from this forum, in which the first page says it's for i30 Elantra Neos (I guess it applies to i30cw as well), short presses (less than 1 second) on Trip button will switch between 4 different types of display and long presses (longer than 1 second) will reset tripmeter. For mine, though long presses work, the short presses don't work - there is no response. My car is basic version. A quick question would be: The Trip button and trip computer are the same on basic version as higher (more expensive) versions like SLX, right?

I noticed the difference between the first half and the second half. As mentioned above, when it's 1/2 tank, it had traveled 290KM. Now it's close to 1/4 tank, it's traveled about 400KM. Following this road, it will be about 500KM for a full tank. Well, since I haven't brimmed the tank, it's 500KM for almost a full tank. Does it sound normal to you?

By the way, I've had this question in my mind for a while. How do you guys test driving a full tank? Do you drive the car till it cannot move? Do you prepare and carry some fuel on the car when doing that? Otherwise, how do you get your car to move after it runs out of fuel and shuts down? The reason I'm asking this is that the zero position of the hand isn't overlapping with the zero scale mark so I can hardly tell when it's close to zero fuel. Maybe the trip computer can help here?

[beerman]

G'day again,

If your I30 is a SX (base model) you do not get the trip computer. It is as simple as that. If it is an SLX you have a problem, but the SX only has a trip odo.

I don't like to go much over 900k in my CW before refilling, usually I have 4-7l left (brimming the tank which takes it close to 60l and by brimming I mean I can see the diesel (not the bubbles) at between 5-10cm from the opening.

Though as stated I spend most of my time on the highway, according to the GPS my average trip speed for a trip to work is 95 km/h. Though I do kill the economy a bit with speed (I dropped from setting the cruise at 120 to 110, it made a difference, but not enough for me to keep doing it).

I suspect your fuel economy is being impacted by sitting still in peek hour. If you have a GPS and it can do an average trip speed, check it out and see.

Otherwise, take a nice long trip on the highway at the posted speed, brim the tank, and do the same at the end. See what figures you get. If I can do 998k with a loaded (and I mean loaded) car, 2 adults and 2 children on the Brisbane - Sydney trip, you should be able to do the same on the open road. I suspect it is the conditions you are encountering on your commute rather than the vehicle that kill your economy.

[Dazzler]

  

Thanks Beerman (nice explanation) 

We try to avoid running out as you risk sucking dirty fuel up from the bottom of the tank.... and although i think the diesel is self priming it would take a while to get it started when you refill 

[Doggie 1]

 

Thanks Beerman (nice explanation) 

We try to avoid running out as you risk sucking dirty fuel up from the bottom of the tank.... and although i think the diesel is self priming it would take a while to get it started when you refill 

Speaking from experience, it's not self-priming.
It's something that you just have to do manually.

[Phil №❶]

How long does it take to prime. db08 

[Doggie 1]

It's very easy actually.
When I ran out of fuel, while I was waiting for a friend to turn up with the fuel, I read the owner's manual and it explained very simply what I had to do and it was all done within a couple of minutes. 

[Phil №❶]

I had read about it but didn't know how quickly the juice got sucked up to the filter, thanks 

[Doggie 1]

Yeah, almost instantly. No problems at all.

[ausi30]

Hi,
we have a 2010 slx cw auto crdi with 34000 ks on it
just completed a round trip  Brisbane to Stanthorpe and Tenterfield with a mix of good highway driving and mooching around the wineries. Before leaving I brimmed the tank(bp) .  we travelled 830 ks with 3 up and a bootfull of wine and had just under 1/4 tank left on getting home. Computer showed average of 6.1 l/100 ks. Refilled with 44 litres back in Brissie, same garage. Our average around town(wife is main driver) is 7.5 to 8.5.
Only problem we had was with starting the car in the morning. just did not like to fire up even after 2 operations of the glowplugs. but is was cold getting down to -3C...
Don

[Dazzler]

Thanks for that Don (interesting) Bit surprised about the starting though (even at -3) 

[TazManiac]

I did a sum up of fuel consumption in the last year. It's about 7.85L/100KM.

I'm not sure why my 2.0 petrol is getting better economy than your diesel... I did 644km from a tank of petrol and it worked out to 7.53L/100KM.

[noob]

I suspect your fuel economy is being impacted by sitting still in peek hour. If you have a GPS and it can do an average trip speed, check it out and see.

My GPS navigator cannot do average trip speed. However, I have an app named Sports Tracker on my Android phone, which is supposed to be used for sports but can calculate average speed. I ran it this morning. The result is an average speed of ~20KM/h for a ~9KM trip. The full distance from my home to office is about 12KM by the way.
Is the speed (way) too low for a good fuel economy?
Will try the app more times to make sure it works correctly.

[Phil №❶]

IMO that is very low. At 20 kmh the car theoretically is never in top gear. Because it's an average, naturally you do reach 60 kmh but it must be very briefly. An average of 50 would make a huge difference to your fuel consumption. Is there anything you can do to lift the average, eg leave at a different time etc.

[noob]

There is actually no need for more testing of the app. Normally the 12KM trip took me about 30-35 minutes when there is no traffic. This is about 20-25KM/h.

Traveling earlier can only avoid traffic. I guess it's the red lights causing the average speed to be low. I cannot think of a way to avoid that.

[Phil №❶]

That is terrible traffic flow, where are you located 

[beerman]

You use a lot of fuel getting the car to move from a stop. You may see improvements by rolling up to lights etc. But this may prove impractical in heavy traffic.