Stop at 50% when refueling?

[ILoveMyNGV]

Hi all,

I am new to this forum but have owned my 2009 Honda Civic GX since November last year.

One question I have is about refueling, I refuel in SoCal and I noticed that the refueling process pauses at 50% then continues.

But a few times it has broken at 50% and not continued on.

The reason for my question is that normally I get between 230 and 250 miles to a tank, this is at 3600psi. But when the refueling system breaks at 50% I expected to only get around 110-125 miles. Imagine my surprise when I was able to drive for 235 miles before the light came on... This was on a 50% fill.

Anyone know what is done after 50%? I mean if I can fill my car only 50% I can save about 7$ filling my car up. Also, is there any chance of receiving damage when doing this long term?

I have tested this by actually cancelling the fill at 50% and I still am able to reach over 220 miles without any issue.

Just curious.

[Alaska GX]

Re: Stop at 50% when refueling?

Using my FMQ2-36 i was having a hard time getting my cost below 4.9 cents a mile for fuel on my 09 GX.

I started turning off my FMQ at what I guessed was about 3000 psi....fuel cost droped to 4.5 cents a mile.

Works fine at home....

Does your ' 50% fill ' reach the 3000 psi mark on the GX guage ?

220 miles seems like a lot of miles for 50 %

[ILoveMyNGV]

Re: Stop at 50% when refueling?

It goes all the way to the 3600 psi mark.
But even when I fill up at SDGE's 3000 psi stations the fuel indicator shows 3600 psi. (2nd mark farthest to the left)

[freedml]

Re: Stop at 50% when refueling?

Sounds like the indicator that showed "50%" was broken.

We've had this discussion in detail. There is just no way to calculate your gas usage accurately without special equipment.

[ILoveMyNGV]

Re: Stop at 50% when refueling?

Sounds like the indicator that showed "50%" was broken.

We've had this discussion in detail. There is just no way to calculate your gas usage accurately without special equipment.

I guess I should clarify, the 50% guage is mounted in the CNG station pump, not my car.

[CraziFuzzy]

Re: Stop at 50% when refueling?

Those % displays are just VERY rough guidelines. It's just so that they have some way of letting you know how much longer it'll be filling, and so when you see the arbitrary numbers increasing, you know stuff is still going on (other than the flow-noise). Don't put too much faith in them NUMERICALLY.

I think most of them are designed to approximate the TIME it will take to finish filling, and not necessarily the completion of fill. Because the CNG tanks do not fill linearly (Flow rate drops as tank pressure increases), 50% TIME is not 50% full. (It's probably closer to 80%, which you seem to be seeing with your mileage results).

When you see the filling stations stop part way, and then pick up again (seemingly with higher flow rates), this is because that dispenser has stopped to switch to a tank that is at a higher pressure. It is cheaper to compress gas into the LOWEST pressure tank in their yard, and as such, it will also draw from a lower pressure tank as long as it can still fill (is still; higher than YOUR tank). Then, as the flow rate drops off, it realizes it needs to use the higher pressure tank to continue being able to push into your tank. It's not necessarily at a set % mark, it will actually ussually fluctuate based on how 'full' the station is.