Gasoline fuel pump tricks - how do gas stations cheat on us? (1 Viewer)

[se7en6]

I recently drove the GRJ76 (current J7 gasoline option) with the 130L tank to a gas station in south-eastern Europe.
It was an old station, really used up. The pumps looked so old, I was a bit worried, but it was the last station before going on a long highway trip, so I went.

The needle was still between E and the first line. The orange fuel pump indicator was lit. To me that means something around 100 liters to top up.
But:
They filled it up and charged me for 122 liters.
I had never filled up this much before.
A bit confused I went on my way and kept thinking about how they managed to cheat me 10-15 liters.

My experience (45k km+) when filling up from the needle below E is usually like this:
I top it up with around 114 to 118 liters. I never got it to fill up more than 118L, because I usually start sh*tting my pants when the needle is below E.

So it is obvious that they cheated around about 15 liters. Also statistically speaking the usage went up a few liters/100km. I keep track of that since day 1.

But how did they do it?

Consider that in this area people don't usually fill up more than 70 liters of gasoline, it's uncommon there to have vehicles/trucks with gasoline engines and 130L/2x90L tanks.

So how did they do that? I remember, that the fuel pump stopped about 2/3 into the filling, all by itself. I ask the guy if everything is OK with the pump and he mumbled something unintelligible.

Some time soon I may pass there again and I thought I may try them again with an all empty tank, literally let it run empty, then fill up 2 liters and visit the gas station again. My prospect is that they will charge me with more than 130L and thus proving their cheat without a doubt.

What is the trick here?


PS: sorry for not using imperial, we're metric here in the rest of the world.

 

[gnob]

yes stations do this. in the usa we have a department that audits fuel pumps for accuracy.

 

[SNLC]

Common in Latin America.

Before you open the gas cap, you look at the pump to see it zeroed out. Then you stand there and watch them pump the fuel.

I have only had it happen when I wander off and don’t watch them.

Cheers

 

[se7en6]

So, there are at least two ways to cheat me:
- Have the clock above 0 Liters before filling up. Solution: Check clock to be at 0L before filling up.
- Manipulate the meter to tun faster, thus faking more gasoline output resulting in higher payment, while less was sold. Solution: ??? How could I check if the amount was right. I can only do so with an all empty tank, right? Or is there another trick?

Also, poor fuel quality or mixes with other liquids can be used to cheat us, right?
What kind of mixes are happening in the real world? What do they put in to "stretch" the quantity?
What affordable equipment could I use to check fuel quality of gasoline?