22 gallons into a 20 gallon tank?

[MarkC]

I've been wondering about this for a while.
According to my owner's manual, my Cherokee has a 20.2 gallon tank. I've never been able to get more than about 19.5 gallons into it, no matter how empty I thought it was. In fact, when I fill up at the nearby Chevron, it takes forever to fill, the pump begins shutting off after I get it about half full. When I go to the Shell station, I can get what the pump claims is 22 gallons in there. The pump doesn't shut off prematurely like the Chevorn one does, but at both places, just as an experiment, I fill until I get the fuel level right up to the top of the filler neck. I knwo you're not supposed to do that, but I did it just to be able to compare.
So, is the Shell pump giving me false readings? How can I get more gas into a tank than it's supposed to hold? This only happens at Shell.

 

[Pablo]

What are you using to tell exactly how empty your tank is?

The largest error adder is the cockpit fuel gage.

Your tank will never be completely empty....even in some car when you "run out of gas".

AS for 22 gallons....that does seem a bit interesting, but maybe your beast really holds 23 or something.

 

[Whimsey]

Are you saying that with the Chevron pump the most you can fill your 20.2 gallon tank with is 19.5 gallons. Which makes sense because some of your tank space is taken up the pumps/pick up and emission equipment. If the Shell pump says it can put 22 gallons in your 20.2 gallon tank then I'd say the Shell pump is set wrong. Either intentionally or accidentally both are illegal because they are ripping you off. In NJ we can contact the states Weight and Measurement Bureau who certify all gas pumps. I've read where station owners can "monkey" with the counter but when the state reconciles the "gallons sold" with delivery records they can tell if there was any "hank panky" going on

.

Whimsey

 

[55Test]

Some tanks can be overfilled, some can't. My brother's 93 Civic's tank only holds 43 liters, but he can get 40 liters in it when it hits the E mark, and there's enough fuel in the tank when it's on the E for about 70 miles of driving.

 

[Hirev]

I would have this place checked out through the Washington State Dept of weights and measures. here at [email protected]. They are responsible for the pump checks. If your owners manual says it only hold 20.2 gallons and you are putting in 22 gallons.

I have herd there has been a surge of complaints since gas prices went up so much. They had a guy in the golden state that managed to get 4 more gallons of gas in the tank than the owners manual stated. Turned out the pump was tampered with.

 

[Gary Allan]

Before filing a complaint, just get an empty 1 gallon gas jug. Fill it at either station. Note level (accurately mark). Fill at other station. Note level. If they are different ..make the call.

In PA the pumps have the stickers right on them to tell you when they've been tested.

I like CA's covert testing program. The car is set up that the filler neck doesn't go into anything but a 5 gallon tank. The lady (in the expose~) shouldn't have been able to fit more than 5 gallons into it. If she did the metering was off. They found all kinds of ways that independants would fool even the electronic equipment.

This is a lot different from when I would just turn down the price and fill my tank @ $0.25. Took the boss quite a long time to figure out what I was doing. He was quite angry. Not at the deception or the rationalized theft ...but the mental effort that he put into trying to figure out why the gallons pumped never quite matched the $$$ pumped. He really did like me, I guess. I never outright just stole anything in my youth. I always seemed to be able to find the loop hole ..the unchecked in checks and balances. Luckily I gained just enough wisdom to figure out that I was too lousy a liar to cover up anything I did wrong ..so I wisely abandoned the practice. Dangerous combo antisocial tendancies and candor ..they just don't mix.

 

[JHZR2]

often there is a stated tank volume, but it does not include the reserve capacity of an extra x gallons.

Usually youre using this reserve when your gas light comes on, sometimes not even.

In my chevy truck, the gas light comes on with 5+ gallons left in the tank. Thats because it uses fuel for cooling. Seeing the light makes me want to add gas soon, so their mission is accomplished.

JMH

 

[BeltwayBandit]

Mark,

Depending on the design of your fuel pump/gas tank, you may not want to run you tank so empty. If your fuel pump is in the tank it uses the gasoline as a "coolant" for the pump. I have usually heard the recommendation to refill at 1/4 of a tank to make sure there is enough gas in the tank to keep the pump cool.

Gary's gas jug idea will give you the data you need and keep your fuel pump happy.

Good luck.

 

[MarkC]

I don't usually like to run it that low, but sometimes it happens. The way I tell it's completely full is that I fill it up and up and up, until I actually see fuel sitting as farvup the filler neck as it will stay without overflowing.
I've had this thing for 7 years and I'ver never been able to put this much gas in it, and Chrysler says it's a 20.2 gallon tank.

 

[Pablo]

Markc- your last statement really made me think some hanky panky IS going on with that station.........

 

[MNgopher]

Mark-

I've run my Cherokee bone dry (don't ask how or why

), and I have the same sized tank. I was only able to get a hair under 21 gallons in filled to the brim full, as you've described. 22 gallons sounds like a stretch...

Of course, my F150, about 2 gallons over the stated capcity sounds right (again - don't ask

)

 

[Dr. T]

I've run my car bone dry too (on many occasions) and have never been able to fill more than the tank says it holds. The most was within 1.5L of max (91L).

I'm filling at a new station now that also fills about 1L less than the previous station I used to regularily fill-up at. So I agree with the pump inaccuracy statements...

 

[rgl]

quote:

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Before filing a complaint, just get an empty 1 gallon gas jug. Fill it at either station. Note level (accurately mark). Fill at other station. Note level. If they are different ..make the call.

---

I have heard that with the computerized pumps it is possible to set them up to pump accurately the first few gallons and then start pumping inaccurately for larger quantities in order to circumvent the state test equipment.

 

[Matt_S]

quote:

---

Originally posted by Pablo:
Markc- your last statement really made me think some hanky panky IS going on with that station.........

---

...which makes me think you should report it to the state agency that handles this. In Michigan it's the dept. of agriculture (weights and measures). I don't know about Washington, but they may very well put inspection stickers on there that would indicate who to call.

 

[XS650]

I've run my 95 GMC S-15 bone dry a couple of times, in the interest of science of course.

It takes about 1/2 gallon less than rated capacity. It also runs out right when the needle is centered on the "E" mark. The gauge is very accurate that way. Now if I can just find someone to watch it for me...

 

[MarkC]

Did it again yesterday. 21.4 gallons, and I filled it up to the rim, so I could see the gas sitting there. The gauge wasn't reading as far to the left of E as before either, I was anticipating about 18 gallons.
Next time I'll use the Chevron pump and see what happens.

 

[Clement]

In my Hyundai Accent (2002) with the needle on E, it only takes about 8 to 8.5 gallons to fill the tank. The tanks listed capacity is 11.9 gal. Also the fuel pump is on the top of the tank, so the discrepancy shouldn't be for fuel pump cooling.

I'm not brave enough to drive 100+ miles past the E mark to see what I can fit in it. Actually, I usually don't let it get past 1/4 tank.

 

[Kestas]

I would do what Gary Allen suggested, run an experiment of filling the same container from two different sources. Every experiment needs a control sample. Better yet, document your actions so the State governing acency can have proof of how long it's been allegedly going on and they can subpeona the station's records to determine the fine.

Even if you don't do that, go with your feelings. You know the pattern of filling your tank, and it seems that this station doesn't fit the pattern. Do the public a favor and pursue this.