Thursday 1st September 2011

PH Fleet Update: Infiniti G37 S Coupe

Why a fuel gauge can make you angry

---

L55 UST looking all innocent...

There are many facets of the PH Fleet Infiniti that I will defend to the hilt - I love its relaxed cruising gait, its air of quiet, unpretentious luxury (though some will disagree with that), and I'm constantly impressed at its ability to pick up its skirts for a twisty-road run.

But there is one thing that irritates me - its fuel consumption. Actually, scratch that - it's not the fuel consumption that's the issue (it'll do something between 24mpg and 29mpg, depending on how much stick you give it), so much as the fuel gauge itself.

Much as any sane human being I like a constant, measured range-meter - I want to know how far I can go before I fill up. For some reason, however, the G37's prediction of how much fuel it has left fluctuates wildly, depending on how you are driving at that precise moment.

...while this simple readout causes misery

Thus, when I left my house this morning it told me I had 43 miles left before I needed to find a petrol pump. This then went up to 47 miles before plunging to just four miles. With another 15 miles of my commute left to run. This, admittedly, was when I was haring around one of those endless curved sliproads that join to motorways (just to wake myself up, you understand), but the trip computer really should have been aware that I wasn't going to drive like I was escaping the police for more than a few seconds.

The computer then recovered its dignity over the next section of road - to the point where it told me I had 41 miles as I trundled into PHHQ. The most frustrating thing about all this is that the needle on the conventional dial follows the same path as its miles-to-empty digital cousin, meaning it's surprisingly hard to work just how much fuel you really have in the tank.

Now, I'm sure that there are all sorts of valid reasons - both physical and electronic - for this fluctuation. But the fuel gauges in most other cars I drive don't seem to be so sensitive - so why is the Infiniti's? It's maddening...

Previous Articles:
PH Fleet Update: Infiniti G37 S Coupe
PH Fleet Update: Infiniti G37 Coupe
PH Fleet Update: Infiniti G37 Coupe
PH Fleet: Infiniti G37 S Coupe

[MattDell]

I would like to add another layer of irritation to the fuel gauge (range meter)... it disappears altogether if you don't put wiper fluid in!

Edited by MattDell on Thursday 1st September 13:39

[Riggers]

MattDell said:

I would like to add another layer of irritation to the fuel gauge... it disappears altogether if you don't put wiper fluid in!

Well, the gauge doesn't - but the range-meter does. Though even then you can press the button to the top-right of the instrument binnacle and that clears any warning messages. I think.

[Ocho]

If it went down to 4 miles while you were blasting round a long bend, that almost sounds like all the remaining fuel was forced up the side of the tank and confused the hell out of the system that was wondering where it had all gone.

I thought that fuel gauges were a little more advanced than this and that this was a problem we left behind in the 80s, but it would appear to be a part of the issue here...

[71tuscan]

Sounds so very much like a 50 year old Smiths fuel gauge on a 60's fuel tank designed in a barn...
Apart from the fact that was 50 years ago and I suppose/hope the Japs don't have that much barns that are suited to design/build cars as ol' Europe/Britain has/had.

[toho82]

I had the same bugbear in the 370z!

One minute you're cruising alone the next you're desperately trying to locate the nearest petrol station. Was never really sure how much was really left in the tank and would drop off completely after 25 left which was a worry...

[Riggers]

Ocho said:

If it went down to 4 miles while you were blasting round a long bend, that almost sounds like all the remaining fuel was forced up the side of the tank and confused the hell out of the system that was wondering where it had all gone.

I thought that fuel gauges were a little more advanced than this and that this was a problem we left behind in the 80s, but it would appear to be a part of the issue here...

Exactly - a modern car brain really should know better... still, if that's all I've got to complain about (apart from the gearbox, which I don't like overly much)...

[pSyCoSiS]

Not as irritating as sitting in traffic in an old XJ40, seeing the fuel needle go down!

[louismchuge]

pSyCoSiS said:

Not as irritating as sitting in traffic in an old XJ40, seeing the fuel needle go down!

Ha, so true! And the range fluctuates wildly. Although I do like to see how low I can get the instant MPG readout!

[Rusty-C]

Riggers said:

MattDell said:

I would like to add another layer of irritation to the fuel gauge... it disappears altogether if you don't put wiper fluid in!

Well, the gauge doesn't - but the range-meter does. Though even then you can press the button to the top-right of the instrument binnacle and that clears any warning messages. I think.

While we're at it (and by the way, I do like the "Almera"), the serious lack of rear hedroom mean it is only really comfortable in the front for a 6 footer; no rear armrest seems like a strange omission, too. Apologies for the What Car? notes but alas, ive never driven it...

[Garlick]

Just put some fuel in it you tight bugger.

[Draexin]

Reminds me of a Peugeot 207 I once drove, it suddenly decided I had 0 kilometres range left... which is quite panic inducing when you're driving along on a busy motorway.

[Riggers]

Garlick said:

Just put some fuel in it you tight bugger.

No need yet - its still says it's got 41 miles left to go

[Guvernator]

Is this really that unusual?? Most if the cars I've driven which have a digital fuel gauge or mpg trip computer have done this including all the well known German marques. The MPG display gallops up if I'm sitting at 65 on a motorway but as soon as I turn off the sliproad and sit at some lights for a few seconds it plummets down again. Admittedly the fuel gauge disappearing is a bit unusual but I thought all the other symptons were par for the course on most cars equipped witha digital fuel readout. Afterall the whole point of the clever car brain is that it's supposed to work out how far you can go depending on how you are driving. Not really sure what the problem is here?

[Arun_D]

Guvernator said:

Is this really that unusual?? Most if the cars I've driven which have a digital fuel gauge or mpg trip computer have done this including all the well known German marques. The MPG display gallops up if I'm sitting at 65 on a motorway but as soon as I turn off the sliproad and sit at some lights for a few seconds it plummets down again. Admittedly the fuel gauge disappearing is a bit unusual but I thought all the other symptons were par for the course on most cars equipped witha digital fuel readout. Afterall the whole point of the clever car brain is that it's supposed to work out how far you can go depending on how you are driving. Not really sure what the problem is here?

You're comparing an instantaneous mpg readout to a range/distance to empty readout, though. The latter should be clever enough to give a fairly stable value, based on fuel level and average mpg.

[Riggers]

Arun_D said:

The latter should be clever enough to give a fairly stable value, based on fuel level and average mpg.

This. Nail, head, etc

It does seem to be a problem that affects most cars with a digital 'miles to empty' thingummy, but the G37 seems to me to be more sensitive than most

[jakesmith]

On my Boxster it doesn't give a 'live' MPG, just an average of the total journey, that way you don't think 'great I'm getting 40mpg!' for 1.6 seconds as you coast. The miles to empty uses an avearge MPG over the last 20 miles so doesn't fluctuate in this way at all.

[lionrampant]

Wait, so the actual fuel gauge itself changes level fluctuates like that too? Good god that has to be a known design flaw?

[Retset]

My E90 bases range over the consumption over the last x miles ... can't remember x! This makes the range a very useful thing to leave displayed. Sounds like Infinti have made the range reading instantaneous which is plain stupid.

[Ev_]

Interesting... I always thought it was a positive thing that the G37's predicted range responds relatively promptly to your current driving style. At least that way it's not being misleadingly optimistic if you decide to hoon around on those last few litres.

[Guvernator]

Ev_ said:

Interesting... I always thought it was a positive thing that the G37's predicted range responds relatively promptly to your current driving style. At least that way it's not being misleadingly optimistic if you decide to hoon around on those last few litres.

Exactly my point and I'm pretty sure most of the cars I have driven with computerised range meters have done exactly this too, for instance cruising on motorway might show 47 miles left but then if you come off the motorway and either get stuck in traffic or decide to go for a hoon on a B road, it very quickly drops down to 21 miles left or whatever as it responds to the way the car is being driven. Surely you'd want it to do this rather than mislead you into thinking you still had 47 miles left? I really can't understand the issue here??