mpg/miles to the tank/fuel gauge

[T-Bag]

Not had the 172 so just a quick question about fuel usage.. I have searched but not found what I want, no doubt missed it like... sorry if it's asked all the time.

My mpg seems pretty respectable on my daily commute. Filled the tank at the start of the week and reset the mpg etc. I have managed 150 miles, 37mpg yet my tank is nearly empty !? The first 60 miles used half a tank, Is this right ? I'm 1 notch about the red at the mo and its claiming there is another 120miles left.

Is the fuel gauge just crap or what ? It's still costing me a fair whack to fill it up so it does seem to be using a lot, but my mpg is okay? My old Golf only did about 34mpg, same sized tank (from what I can gather) but did twice as many miles before needing to be filled.

 

[Griff]

The fuel gauge isn't linear which makes it look like you've used loads of petrol and have hardly any left.

 

[SC03OTT]

that seems right to me (i dont have a 172 though). i get 300-320 miles to a tank, so 1/2 of that would be 150ish

 

[Ian_182]

Something doesnt sound right

 

[SC03OTT]

i misread the original post, sorry

 

[d-anie-l]

the computed mpg is out by around 2mpg. I have tracked my mpg over approx 5000miles and know exactly what my REAL average over that time is versus the onboard average.

You should be getting around 320-340 miles to a tank when your onboard mpg figures shows 36+.

 

[-Leigh-]

The tank is 50 litres. At 37mpg you should be getting about 320 miles to a tank before the light comes on I'd imagine.

I can do about 160 miles until the needle sits at half way. I normally get about 280 miles to a tank.

 

[pete_clio]

i just filled mine up there, got 270, just above the red line, took 40.44 litres to fill. similar last week and that was 33mpg.

 

[T-Bag]

Alright cheers, if the 'miles remaining' is actually correct then it's not far off. It's just slightly discouraging watching the needle go half way in 60 miles or so

 

[-Leigh-]

I find I do more miles to the first half of the tank than the scond half!?!

Expect they're all different lol

 

[Fletcher]

^^^^me too.

 

[Noodle999]

I know the Clio fuel gauges behave a little strangely but the needle going down from full to half in only 60 miles does sound a bit abnormal to me. To give you an example I filled up yesterday and then did around 80 miles which took me to a tiny bit above 3/4 on the gauge, I wasn't hanging about because it was late at night so the trip computer read a fairly poor 25.5mpg afterwards.

So for my gauge:
50 litres = ~10.99 gallons, so 1/4 tank is 2.75 gallons, 2.75 * 25.5 = 70.1 miles, which is inaccurate but not far off the 80 miles I did.

...but for your gauge:
1/2 tank is 5.5 gallons, 5.5 * 37 = 203.5 miles, whereas you only did 60 miles until the needle had fallen to half, a disagreement of 143.5 miles.

Even if we consider my gauge being out 10 miles at 3/4 tank means it'd be out maybe 20 miles at 1/2 tank, yours is still around 120 miles more inaccurate than mine, and in the opposite direction. Like I said we all know the gauges behave a bit weirdly but this still seems a bit iffy to me :S As others have said what I find with mine is I do more miles with the first half of the tank than the second (as demonstrated by the calculation above for my journey last night).

What I'd do if I were you is keep an eye on it, you can monitor your car's current measurement of fuel more closely by entering the diagnostic mode on the instruments (with the ignition off, hold down the trip computer button on the end of the stalk and turn the key to position 2). Once you're in the mode where it's making a silly noise and the instrument needles are dancing around press the stalk button again and you should see a reading in litres which is exactly how much fuel your car believes it has in its tank at that moment. To return things to normal turn the ignition back off.

 

[BMark]

I know what you mean about the reading being a bit funny. My needle read empty for about 20 miles before i filled up last time and the trip computer said i had 30 miles left. The light hadn't come on though and I only put 45 litres in so it did have a bit to go.

 

[bmh.01]

I've just done 300 miles to my last tank and I think thats pretty crap tbh! I find the first 1/3 of the gauge shoots down really quick then it takes ages to go through the middle.

 

[Russ_16v]

im gettin about 250 miles to a tank atm ! not good!

 

[skinner]

Yours does sound worse than most.

Mine does 100 miles to the first half and 200 for the second half.

 

[T-Bag]

It does normally do a bit more than that on the first half to be fair.

I filled up today and did a manual calculation based on how much fuel I had put/miles since last refil in and I worked it out that I was getting closer to 25mpg.

I'll just see how it goes, I wasn't expecting super fuel economy or anything

 

[BMark]

I worked out what I did from the last tank and it was 29 mpg. Considering I got it about a month ago and i'm now getting much more used to the car and driving it pretty hard everywhere I don't think that is too bad.