Pumping Gas (YACT)

imported_Trippin315

Golden Member
Nov 23, 2004
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It is just a question and here it is.
When one fills up their tank, how does the pump know when to stop so it does not overflow.

The only reason that I ask is that the pump overfilled my car by what I would guess a quater gallon. That may be a bit on the high end but lets just go with taht number.

Is it a faulty pump or is there something in my car that I should get looked at?

It has never happened before which does not really mean anything.

Advice, please.
 

mcvickj

Diamond Member
Dec 13, 2001
4,602
0
76
Hmm. Good question. The pumps I use always stop too soon. I always top off my tank.
 

amdskip

Lifer
Jan 6, 2001
22,530
13
81
Faulty pump, theres gotta be something in the nozzle thats a float type thing to detect how much gas is in it.
 

Demon-Xanth

Lifer
Feb 15, 2000
20,551
2
81
I've only had one time when the pump overflowed. That was because I was washing my windshield the it slipped up a bit. I beleive that the way it works is based on pressure. When fluid hits the nozzle, the pressure suddenly increases as it's no longer flowing freely.
 

olds

Elite Member
Mar 3, 2000
50,125
780
126
It's controlled by the dispenser nozzle.
Overfilling is bad as it can damage the smog system on some cars.
 

dullard

Elite Member
May 21, 2001
26,120
4,769
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There is a sensor in the pump nozzle. Either (a) the pump is not functioning properly or (b) you didn't put it properly into your car.
 

imported_Trippin315

Golden Member
Nov 23, 2004
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Originally posted by: dullard
There is a sensor in the pump nozzle. Either (a) the pump is not functioning properly or (b) you didn't put it properly into your car.
I cant think of more than one way it insert stick (a) into hole (b) so let us not assume user error.

 

olds

Elite Member
Mar 3, 2000
50,125
780
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Originally posted by: Trippin315
Originally posted by: dullard
There is a sensor in the pump nozzle. Either (a) the pump is not functioning properly or (b) you didn't put it properly into your car.
I cant think of more than one way it insert stick (a) into hole (b) so let us not assume user error.

In CA it has to seat correctly or it won't dispense at all. That's what activates the overflow protection.
 

DivideBYZero

Lifer
May 18, 2001
24,117
2
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Originally posted by: oldsmoboat
It's controlled by the dispenser nozzle.
Overfilling is bad as it can damage the smog system on some cars.

You're thinking of oil, not gas, surely? Or are you talking about the tank vent?
 

dullard

Elite Member
May 21, 2001
26,120
4,769
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Originally posted by: Trippin315
I cant think of more than one way it insert stick (a) into hole (b) so let us not assume user error.
That statement makes me think it very well could have been user error. You can put just the head in, or you can plunge it deeply in - depending on your GFs preference. Oh wait, this is a gas pump question. Oops. If it wasn't inserted all the way in, it won't likely work as designed. Spillage can then happen.

 

imported_Trippin315

Golden Member
Nov 23, 2004
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Originally posted by: dullard
Originally posted by: Trippin315
I cant think of more than one way it insert stick (a) into hole (b) so let us not assume user error.
That statement makes me think it very well could have been user error. You can put just the head in, or you can plunge it deeply in - depending on your wifes preference. Oh wait, this is a gas pump question. Oops. If it wasn't inserted all the way in, it won't likely work as designed. Spillage can then happen.
Trust me, I always make sure that it is in as tight as it will go. I hate spillage in all forms.
and fixed.

 

Demon-Xanth

Lifer
Feb 15, 2000
20,551
2
81
Originally posted by: DivideBYZero
Originally posted by: oldsmoboat
It's controlled by the dispenser nozzle.
Overfilling is bad as it can damage the smog system on some cars.

You're thinking of oil, not gas, surely? Or are you talking about the tank vent?

There's a whole evaporation system that's built into the car containing sensors, a carbon canister, a pump, and other crap that would have seemed completely dumb 40 years ago but will light up a check engine light if your gas cap is loose.
 

olds

Elite Member
Mar 3, 2000
50,125
780
126
Originally posted by: DivideBYZero
Originally posted by: oldsmoboat
It's controlled by the dispenser nozzle.
Overfilling is bad as it can damage the smog system on some cars.

You're thinking of oil, not gas, surely? Or are you talking about the tank vent?

Gas. Some cars have "charcoal" canisters that somehow filter vapors. The gas can run up the line and fill up the cannister destroying it's function.