Fuel economy dial thing...

[oktapod]

I've noticed that the little gauge/dial that shows fuel consumption has a disturbing propensity to spend its time at the far right nearly all the time - unless I'm being very gentle with my right foot and coasting. In fact, I'm obsessing about it. Trying to make that bloody needle move to the left.

My question is: is it in any way accurate? Trip computer reckons I'm getting 26.9mpg, occasionally 27.1mpg, based on 95% very boring, careful and economical driving and the occasional little blast. This seems a wee bit low, but then it has a 3 litre engine so I suppose I shouldn't be surprised.

What IS surprising me is just how little I need to accelerate at all for that dial to shoot to the right and stay there. EVen very very docile acceleration - say, 10 seconds 30 to 40mph in a high gear - and the needle tends to stick to the far right until my speed settles...

It's driving me nuts... is my car REALLY that thirsty?

None of this changes the fact I really like the car, even if (for three litres) it isn't the discreet flying machine I'd rather hoped it would be...

[Jespin]

That guage is for instant consumption not average so it will always read heavy whilst accelerating, no matter what gear / speed. As you say, when holding a steady throttle it is fine. Don't worry about it.

[Huff]

Think of it like an old-fashioned vacuum gauge (in fact it's a bit more sophisticated than that, because it's based on injector dwell time) - if you want to be economical it's an excellent guide, but not the whole truth. For example, I think its utility is in showing you how little you really need to modulate the throttle to make good-enough progess in traffic vs. what you might do otherwise.

And also truly hilarious when you 'press on' ( I run an E34 540...)

I've also found it's not far out at all if cruising, e.g motorways where you are likely to hold a near-constant speed (load) for miles.

[LordGrover]

If it's not firmly glued to the right you're doing it wrong.

[GreenV8S]

oktapod said:

It's driving me nuts... is my car REALLY that thirsty?

I think it's telling you the opposite. When you're holding constant speed the engine is just putting out enough power to overcome the drag and rolling resistance. When you open the throttle, it has apply enough force to accelerate the car plus the drag and rolling resistance. If you note how quickly the car would slow down if you dip the clutch, that tells you how much drag and rolling resistance there is at that speed. For example if it slows down by half a mile an hour per second, then when you accelerate by half a mile an hour per second you've just doubled the engine's power output.

[jdwoodbury]

I find the gauge totally pointless, it has 2 modes...pinned to the right below minimum reading or about 30mpg (545i)

[cushT]

It is best to ignore it whilst accelerating as the reading means bugger all, just use it when you reach cruising speed

[benny 61]

i watch my fuel gauge dial quite a lot but if a nice bit of road comes up i still accelerate hard you cant have it both ways you never buy a 3ltr engine for fuel economy do you ?

[dcb]

oktapod said:

I've noticed that the little gauge/dial that shows fuel consumption has a disturbing propensity to spend its time at the far right nearly all the time - unless I'm being very gentle with my right foot and coasting. In fact, I'm obsessing about it. Trying to make that bloody needle move to the left.

My question is: is it in any way accurate? Trip computer reckons I'm getting 26.9mpg, occasionally 27.1mpg, based on 95% very boring, careful and economical driving and the occasional little blast. This seems a wee bit low, but then it has a 3 litre engine so I suppose I shouldn't be surprised.

It's driving me nuts... is my car REALLY that thirsty?

Yes - you don't tell us what you've got, except for it's a three litre BMW.

You buy a 150 mph chariot and it will return 25-30 mpg in ordinary driving.
Less if you drive it in town a lot.

The only way I've found to get over 30 mpg consistently is to sit in lane 1
and drive it like a pensioner, which somewhat misses the point.

Perhaps sir would prefer a two litre BMW next time ?

[cushT]

dcb said:

oktapod said:

I've noticed that the little gauge/dial that shows fuel consumption has a disturbing propensity to spend its time at the far right nearly all the time - unless I'm being very gentle with my right foot and coasting. In fact, I'm obsessing about it. Trying to make that bloody needle move to the left.

My question is: is it in any way accurate? Trip computer reckons I'm getting 26.9mpg, occasionally 27.1mpg, based on 95% very boring, careful and economical driving and the occasional little blast. This seems a wee bit low, but then it has a 3 litre engine so I suppose I shouldn't be surprised.

It's driving me nuts... is my car REALLY that thirsty?

Yes - you don't tell us what you've got, except for it's a three litre BMW.

You buy a 150 mph chariot and it will return 25-30 mpg in ordinary driving.
Less if you drive it in town a lot.

The only way I've found to get over 30 mpg consistently is to sit in lane 1
and drive it like a pensioner, which somewhat misses the point.

Perhaps sir would prefer a two litre BMW next time ?

A 2.0 is just as bad!

[oktapod]

Haha, thanks for the replies. No, I didn't buy a 330Ci for economy, but I do keep an eye on these things. My annual mileage on the car will only be around 5k, so fuel economy isn't really an issue - it was more my idle curiosity and of course if it turned out my economy was particularly bad compared to other 330s, say, then maybe it could have been an indicator of a slight petrol leak or some other issue.

As I think I mentioned, I've not had the car long and I'm only just getting to know it, but the dial thing did sort of confuse me a bit...

[Carmo99]

My X5 has the same gauge and that also stays firmly in the right. My 330i (E92) has a temp gauge in the same place instead. I stupidly asked the garage why the difference. The answer? ..... If you care so much about ecomony buy the 2.0d. (it has it on the BC anyway but I liked the response)