Fuel Consumption on 3.0

[patrickbateman]

usually get around 550+ from a tank

God, you may as well be talking about a totally different car. I've never seen anything with a 4 in front of it, let alone a 5.

Can anyone confirm what the tank in the MY2005/2006 Libs actually is? S&J suggested it was down around 50ish but I'm sure I put about 57 litres in last time I refuelled.

[3rspecb]

64ltr tank.

[J0HNATH0N]

I have put up 8,000kms on my sec b and average 9.8l on the trip. Real usage measurements is around 10.5-11. Can't really complain too much

[Nick770]

It doesn't matter where you are I reckon if your figures are >15 with normal driving the car has an issue that needs sorting out.

I agree, but then again, what is "normal" driving? I've noticed in this thread a few people talk about higher figures as though they are insane and indicate the car has a major issue, but then when you read further, these same people tend to be doing highway kilometres or driving around cities on ring roads or the like.

My usual commute involves no cruising at all. I.e., no phases of driving where the car is in 4th or 5th for longer than a few seconds. Probably a gear change every 15-20s on average, and either accelerating or braking perhaps 90% of the time (as opposed to maintaining speed).

So take a cold car, and drive while constantly up and down shifting at no more than 50km/h and with an average of around 20km/h, and eliminate all parts of the drive when you cruise to any degree. Then as soon as it warms up, turn it off until it's cold again. Then repeat. I'm starting to suspect a lot of people posting in this thread would find their mileage up around 15l/100kms in that scenario.

In short - one of the problems with working out if there is a problem is the inability to compare apples with apples!

Hi,

Thought I'd chime in here even though mine is a 2.5i auto wagon. When I first got the car i was horrified by the fuel consumption, and the more I read the posts of others to try and compare figures, the more depressing it was! I've noticed the car's consumption varies massively depending on the type of driving i do. I also calculate manually by k's driven and litres used rather than go by the display as the display is off by a little bit (display underestimates consumption in my car).

Anyway, pure highway driving with barely any stopping or speed fluctuations and i'll get around mid to high 7's at best.

Unfortunately this was on a trip away and my regular driving is short, stop start, no cruising at all. i work 7 k's from home and apart from being stuck in peak hour traffic for only about 15 minutes a day each way, the rest of my weekly driving is even shorter, to the local shops and back, to childcare, to my parents who live down the road etc. the car barely warms up during every trip. I don't drive like a grandma and will give it a bit every now and then, but nothing too excessive as I normally have a 12 month old strapped in the back. This type of driving gets me on average high 12's to low 13's every tank. My last tank was about 13.4L/100k's. People tell me how ridiculously high this is, but then others who do similar type of driving are getting somewhat similar results. The car has been serviced, the MAF was cleaned, O2 sensors tested and are working fine. It's just a heavy car to lug around over short trips and the fact that I have seen the display down to 7L/100k's i think shows that it is capable of good consumption under the right driving conditions, but obviously the daily driving I do does not produce this at all.

Anyway my point is, whilst i still find my consumption high, i've become a bit more relaxed and accepting of this due to the type of driving i do every week. It's still possibly excessive and there might be something wrong, but I haven't found a solution yet.

cheers
Nick

[jay.ritchie]

Can anyone explain why the fuel consumption would rise 1L/100km (AC not on) while sitting in traffic for 10 minutes?
Never noticed it before, thought it was strange.

[Blitzen06Wgn]

Consumption figure is litres used for every 100km driven. If you sit at the lights with the engine on you use more fuel but don't add to the km so the average consumption rises.

Try going down a steep hill with the throttle closed and the opposite will happen.

[jay.ritchie]

Consumption figure is litres used for every 100km driven. If you sit at the lights with the engine on you use more fuel but don't add to the km so the average consumption rises.

Try going down a steep hill with the throttle closed and the opposite will happen.

Yeah i get that, but does that also mean that while sitting stopped for 10 minutes, the car used 1L of fuel?

[KiDo_Tuning]

Calculation is injector pulse over distance travelled. Sinc the injector size is known, it can rise while sitting at the lights since the factory idle tables burn un-necessary fuel

[patrickbateman]

Appreciate the replies. Further investigations have provided me with a bit more data -

First, the digital display is definitely wrong. Based on litres going into the tank and kms done, my last tank of city driving went at 16 litres/100 kms. Meanwhile the display (which was reset when filled last time) reported 18.2 litres/100 kms. So I've 'found' an extra two litres right there.

Second, going for a long drive mostly at highway speeds over Easter, the car got down to 10 litres/100kms. That includes stopping a few times and some very solid acceleration in overtaking situations.

Third, a properly tuned 3.0r-b takes off like a jet plane in fourth gear at 100+ km/h... so satisfying! Love a car that still punches you in the lower back when you put your foot down at that sort of speed.

So with the recent tune and learning that the display is definitely wrong, I'm less unhappy than I was. 16ish litres per 100km in city driving is bad, but considering the conditions of that driving outlined above, perhaps within the realm of what you would expect. That figure included a bit of pre-tune driving and presumably a bit of the engine running while in at the shop, so I'm hoping the next tank goes at 15ish, which I could definitely live with (compared to 20+!).

[patrickbateman]

Consumption figure is litres used for every 100km driven. If you sit at the lights with the engine on you use more fuel but don't add to the km so the average consumption rises.

Try going down a steep hill with the throttle closed and the opposite will happen.

Yeah i get that, but does that also mean that while sitting stopped for 10 minutes, the car used 1L of fuel?

This is usually only noticeable after a trip meter reset, because smaller kilometres travelled produce larger changes in apparent usage.

If you've travelled 1km since a reset and used 0.1 litres, then the car would report 10 litres per 100/kms (0.1 litres per kilometre).

If you sit at the lights and it goes up to 0.11 litres used (because the engine is still running), then the car would report 11 litres per 100km (0.11 litres per kilometre).

[bretto87]

currently on 608km`s with it saying i have 70km`s left but ill be filling up well before then

[patrickbateman]

currently on 608km`s with it saying i have 70km`s left but ill be filling up well before then

What type of driving?

[RX25SE]

Towing a 750kg camper trailer from Melbourne to Wangaratta and back, the dash was telling me 12.8l/100.
If I could ever be bothered, I might check and see how accurate the trip computer is.

[KiDo_Tuning]

Forum member 6thgear has been averaging 8.8L/100Km's around town having fun with it. 650km's per tank around town is half decent for the H6

[RX25SE]

That's about 180km more than I average!
Do these things run that rich under load you call pull that much fuel out without melting the engine?