Problems with filling stations pump?

[Zebedee]

I've filled up 1/2 a dozen times over the past few weeks at various filling stations across the country with no problems at all. The pumps have always stopped (or at least dramatically slowed down) when 80% of the tank is full.
The pump at the calor centre near my home however doesn't appear to stop at all, even when 80% is exceeded. It also puts the gas is about twice as quick as every other pump i've tried.

I tend to try and work out about how much gas i should have to put in before i fill just to be sure as i have to stop the pump myself.

How can a pump continue to put gas in after the point the 80% shutoff valve should stop it?

[Tubbs]

Obviously got a good pump there ! I wouldn't be too bothered with the 80% thing. It's for expansion in hot climates. Where the temp difference between midnight and midday is far higher than over in the uk. Think about other eu members like Spain and italy and the south of France. All conversion equipment conforms to the e67 regulations. So it's the same throughout Europe. Calor fill to more like 90% and you don't see gas bottles exploding all over the place do you ? And they have far far less safety features incorporated into the valve. At some point it will just shut off before it hits 100%.
Mind you it does kind off screw up your mileage calculations though !

[Zebedee]

I'm still working out MPG as i've only been running on LPG for a couple of months so it does kinda screw up my calculations.
I had one fill with 22.2mpg average (when it switched off at 80%) then the exact same run the opposite direction at the same speeds gave 15mpg when the pump didn't stop so quite a bit more gas went in.
Suppose i'll just have to live with it as its out of my control.

[Tubbs]

See the only way to actually work out your mileage is to use the same pump every time. As you have discovered all pumps are set at slightly different cut off pressures. Or in the case of the calor pump vastly different to everything else you have come across !

[Zebedee]

At least its got a spash guard on the nozzle. One i filled up with at the weekend didn't and my arm got a good spraying.

[SimonHobson]

For MPG calcs, don't bother trying to do "fill to fill" calculations as there are too many variables. Do it over several fills and these variations will even themselves out.

At the risk of being called a sad git, I put all my data into a spreadsheet, and have it calculate the consumption over the last 20 fills - and graph it. I started doing the 20-fills bit when I was filling from bottles, and the only fixed point I had was when I emptied a bottle which signalled another 94l gone in. The trouble was that I almost always ended up with a part used bottle of unknown quantity - so I stopped trying to accurate figures on a fill by fill basis and put down "94" if I emptied a bottle during a fill. Over 20 fills the variation didn't show.

[sijones]

At the risk of being called a sad git, I put all my data into a spreadsheet, and have it calculate the consumption over the last 20 fills - and graph it.

you missed out the MythTV bit, so that makes you a sad geek git

[Zebedee]

The calor centres pump fills my tank to about 92% from what I can work out. 50.2ltrs in a 55 litre tank. All the other filling stations I've tried seem to shut off around 80-82%.

I've been using the Road trip app on my iPod to work out the mpg and am averaging 16.95mpg at the moment done mostly over sub 10 mile journeys.

[Gremlin]

Mind you it does kind off screw up your mileage calculations though !

errr,, why?

[Tubbs]

I was meaning to say if you happen to get a pump that fills to say 90% and then re fill with a pump that shuts off at say 75%. If you work out the mileage you have done, based on the litre's you have just put in it makes it look like you have done more miles. Because you had more gas in the tank basically.

At the risk of being called a sad git

You sad git !!

[SimonHobson]

I was meaning to say if you happen to get a pump that fills to say 90% and then re fill with a pump that shuts off at say 75%. If you work out the mileage you have done, based on the litre's you have just put in it makes it look like you have done more miles. Because you had more gas in the tank basically.

Which is why I now do it over several fills.
I started that when I was filling from bottles. It was difficult estimating accurately how much I'd put in except when I emptied a bottle - so I started just putting down 94l each time I emptied one, and evened it out by calculating ver several fills.

Doesn't make the consumption figures any better though

[richard_ha]

If you really want to track your fuel usage, use this site... here's a list of my cars....
http://www.fuelly.com/driver/richardha

The "Retired" 1993 VTEC was on LPG.

[Zebedee]

Useful site.
Does pretty much the same as the roadtrip app on the iphone/ipod touch though http://itunes.apple.com/gb/app/road-tri ... 98207?mt=8.

I've just taken to typing the cost and mileage in and it works it all out. Best and worst so far are 22.2mpg and 14.79mpg which is quite a difference and could probably be put down to different pumps.

[Rosanbo]

See the only way to actually work out your mileage is to use the same pump every time. As you have discovered all pumps are set at slightly different cut off pressures. Or in the case of the calor pump vastly different to everything else you have come across !

The only way to work out mpg is to go from empty tank (running on petrol to get to the fill station) fill it up and run to empty again, or fill it as many times as you like and record all the litres you put in and then finally read the mileage when you run it to empty.

[john_d]

The only way to work out mpg is to go from empty tank (running on petrol to get to the fill station) fill it up and run to empty again, or fill it as many times as you like and record all the litres you put in and then finally read the mileage when you run it to empty.

nope, cause the software will switch to petrol when the gas reaches a certain level and although in theory it should do it at the same point every time you have to take into account the motion of the car, going uphill, around a corner could push the parameters below the set level and then switch to petrol.

fill up with gas, use the car on gas but dont run out of gas, go fill up, your mpg is then miles/litres * 4.5, thats the only true way to work it ok.

[richard_ha]

The only way to work out mpg is to go from empty tank (running on petrol to get to the fill station) fill it up and run to empty again, or fill it as many times as you like and record all the litres you put in and then finally read the mileage when you run it to empty.

nope, cause the software will switch to petrol when the gas reaches a certain level and although in theory it should do it at the same point every time you have to take into account the motion of the car, going uphill, around a corner could push the parameters below the set level and then switch to petrol.

fill up with gas, use the car on gas but dont run out of gas, go fill up, your mpg is then miles/litres * 4.5, thats the only true way to work it ok.

Except ofcourse different pumps fill to a different level!

The more fillups you take in to account the more accurate it will be.

My individual fill ups ranged from 20.1mpg to 32.6mpg, and averaged out to 24.7mpg over 20,580 miles.
http://www.fuelly.com/driver/richardha/prelude

[Rosanbo]

The only way to work out mpg is to go from empty tank (running on petrol to get to the fill station) fill it up and run to empty again, or fill it as many times as you like and record all the litres you put in and then finally read the mileage when you run it to empty.

nope, cause the software will switch to petrol when the gas reaches a certain level and although in theory it should do it at the same point every time you have to take into account the motion of the car, going uphill, around a corner could push the parameters below the set level and then switch to petrol.

fill up with gas, use the car on gas but dont run out of gas, go fill up, your mpg is then miles/litres * 4.5, thats the only true way to work it ok.

Nope,
Even the same pump can fill to a different level. let alone a different pump will. My pump will regularly overfill usually it fills to 37.5 litres but sometimes I can sit there and put in 44+ litres, I have to decide to stop filling it and release the button otherwise I'd be there all day (joke but it's true).

When you run to empty, to measure mpg, you also have to be aware that empty isn't always empty, (like you said) but it is easily fixed. If you are doing a hard or slightly hard acceleration your tank may cut off, in which case you switch it to petrol and back and just ease off on the throttle and finish the tank like this it may finish completely in 1 mile or 4 miles but it will eventually finish completely.

However 4 miles isn't going to make much difference to your 1000 mile calculation whether it is 1000 or 1004 miles makes next to no difference. But for those geeks who want to be absolutely sure it is easy to completely empty it by switching, and then driving with the lightest foot you can..... (and if drove like this all the time think how high your mpg could be ) eventually when you switch it will cut off as soon as you put it back to LPG IT"S EMPTY!!

[Zebedee]

From empty (taken as being when the engine looses power and won't run at idle) and using the same pump at the same filling station i've ended up with 45 and 50.2 litres being the two extremes. Its a 55 litre tank so 80% is 44 litres. So sometimes the pump stops at just over 80% and other times it gets to over 90%.

I've given up trying to work it out and just put it down to the pump at the calor gas place filling at a much higher pressure than anywhere else.
Not done any harm yet and i usually use a few litres getting back home from filling up anyway so its never sat totally brimmed.