Is the MPG indicator on the dash accurate?

[Balboa]

I was wondering if you guys are using the MPG indicator on the dash when calculating your MPG or if you are going by the number of miles you get per tank. Have you guys compared the two and perhaps find the mpg indicator on the dash faulty? Right now I am getting 51.4 mpg for the last 200 miles. I've gone about 300 miles total and the tank is approximately 65% full.

I'm starting to think the fuel indicator is incorrect because if it's 65% full and I've gone 300 miles already, that means I'm going to get at least another 300 miles and some change...meaning I'd be averaging over 60mpg for street use. Seems off to me considering that I've been mostly street driving.

Most of the driving I have done is street driving with hills. I've been revving high, using a lot of assist, and enjoying it as well.

Did oil change, air filter change, valve clearances, cleaned egr, and spark plug change since I had it.

[Eli]

The fuel gauge is never linear in any automobile. Usually the last half disappears much more quickly than the first half, and this is definitely the case with the Insight.

On average, the FCD is extremely accurate. Depending on your tank MPG though, it can be of by several percent.

FCD     Actual
44.1	43.153
47.2	46.321
49.1	47.582
44.8	44.328
50.7	51.102
59.2	55.113
79.4	84.427
70.5	70.471
55.9	50.836
65.0	69.913
81.7	83.924
69.0	62.597
57.3	58.068
52.6	48.406
65.3	63.342
46.0	45.633
42.7	41.820
41.8	38.809
45.3	43.731
70.2	76.185
50.2	42.899
81.3	82.601
73.7	74.933
66.0	63.984
66.9	66.519
61.8	57.690
61.8	66.929
Average:
59.3	58.65

Mine actually reads high by 1.1% on average.

In general, it reads high at ~50MPG, is spot on at ~70MPG and reads low at 80+MPG.

[gilbertguy]

Same here, the first half of the tank seems to last forever, from half to 1/4 tank speeds up slightly and the last 1/4 tank to 1 bar drops like a rock. I'm usually starting to think about filling up when I hit 4-5 bars left on the fuel indicator.

[madmanmostafa]

It's relatively accurate. Usually I fill up by my mpg and miles driven. So if my FCD reads 54, I know I have a bit more than 540 miles per tank. Since it's a 10.4 gallon tank.

On my fuelly, I have been logging what mpg I get on the fcd and what my actual mpg is. Sometimes it's off by a lot and sometimes it's dead on. Overall, it beats all of the other cars mpg readouts. They're usually optimistic by 5mpg

[Varak]

It is definitely the fuel level indicator being nonlinear that causes the confusion.

In my car, the FCD MPG is consistently about 1-2% higher than the calculated MPG.

This is confirmed by my MPH indicator being about 1-2% higher than what my GPS and roadside radar signs.

It is just calibrated slightly wrong.

[jerrydelrey]

How is the gas tank shaped, is it a trapazoid?

If it's larger at the top then that will explain it.

[Eli]

It's an oval rectanglish deal.

[Balboa]

Ah so I'm not going to get over 600 miles easy for street driving. Oh well.