Fuel pump dispense accuracy

StereoSound

Some of the local garages where I'm living are not convincing me they are dispensing the volume of fuel they should be. Today my local garage was advertising fuel at 124.9. I put in €20 and I didn't get as much for my €20 as I did in another garage the previous week which had fuel advertised at 1.28.

Another thing as well, my local garage has new pumps installed and I notice when I press the trigger on the pump to dispense I don't hear the fuel pump starting until the meter has already read 60 or 70 cents.. That really ticked me off and not sure why it happened but I'm avoiding that garage now from here on in.

Who would I report suspect garages to? I have no idea if there Is a body who test these garages on regular basis.

bluesteel

The NSAI

http://www.nsai.ie/our-services/measurement/faqs.aspx

http://www.nsai.ie/About-NSAI/Departments/LMS/Contacts.aspx

moleyv

aren't they subject to statutory inspections and calibrations?

pippip

moleyv wrote: »

aren't they subject to statutory inspections and calibrations?

Yes but it may be months between inspections.

Having said that op, €20 is not much of a gauge. If they were messing with outputs others filling with €100 would be noticing far more.

As far as the pumps, you said yourself they are new, maybe they work differently to ones where the pump comes on immediately.

Get a 5L/10L can and fill it, see if it fills correctly.

Foxhole Norman

What do you mean by not getting as much? Do you mean not getting more litres or getting less miles out of €20?

223vmax

Take an empty liter bottle and pump 1 liter as per their readout. Do you get a liter and at what price? Fill car to €20 after that.

tphase

StereoSound wrote: »

Today my local garage was advertising fuel at 124.9.

Simple test, put in exactly 10 litres and check the cost displayed on the pump - it should be E12.49. If it's more, stop filling

pippip

tphase wrote: »

Simple test, put in exactly 10 litres and check the cost displayed on the pump - it should be E12.49. If it's more, stop filling

We'll let you think about that one a bit more.

cadaliac

tphase wrote: »

Simple test, put in exactly 10 litres and check the cost displayed on the pump - it should be E12.49. If it's more, stop filling

No, If it isn't calibrated correctly the pump will say that it gave out 10 liters whereas 9. Something liters will be dispensed.
It will multiply correctly.

tphase

cadaliac wrote: »

No, If it isn't calibrated correctly the pump will say that it gave out 10 liters whereas 9. Something liters will be dispensed.
It will multiply correctly.

Of course you're correct. I was coming at it from the perspective of the pump being properly calibrated and the multiplier being adjusted such that the price/litre displayed is different to the price/litre being charged. Probably not possible with modern pumps but I've heard of it happening in the past

StereoSound

Foxhole Norman wrote: »

What do you mean by not getting as much? Do you mean not getting more litres or getting less miles out of €20?

The gauge in my car is reading lower then the previous €20 fill. Its enough to make me question my today's fill. I always let the car tip the red mark on my fuel gauge before filling so I can get a good idea of how much I get for my money when I fill it again. I feel I got feck all fuel today for the price v amount of litres I should have got according to the pump reading. Somthing seems off so I'm gonna look into those links provided above.

No harm in asking for abit of advice on it if I feel I'm being and others ripped off by a poorly calibrated fuel pump.

StereoSound

LIGHTNING wrote: »

Sorry to say it but your method is about as un-scientific as you get.

It is no doubt but I'm not claiming to be doing accurate measurements on every fill up. As an average motorist I'm gaging my fuel fill by my fuel gauge as most of us do. However it would be interesting if my suspicions are worthy of my concern and if not then that's fine too. Better to throw it out there then say nothing.

kirving

Was this in Rathfarnham, Dublin area by any chance? I paid 124.x (probably.9) about 1km after the light came on and put in €20. I did the same motorway journey today, at the same speed as I do every week, and the light was on before I even made it to Galway today.

Completely unscientific as I didn't brim it(as I have been doing so far in 2015), but since the price has dropped recently, €40 has done me for the week. 2x Dublin-Galway runs, and driving 2km to work each day.

Zubeneschamali

StereoSound wrote: »

The gauge in my car is reading lower then the previous €20 fill.

It is far more likely that your gauge is wrong than that the pump is wrong.

StereoSound

Kevin Irving wrote: »

Was this in Rathfarnham, Dublin area by any chance? I paid 124.x (probably.9) about 1km after the light came on and put in €20. I did the same motorway journey today, at the same speed as I do every week, and the light was on before I even made it to Galway today.

Completely unscientific as I didn't brim it(as I have been doing so far in 2015), but since the price has dropped recently, €40 has done me for the week. 2x Dublin-Galway runs, and driving 2km to work each day.

Not rathfarnham but wouldn't be miles away from it either.

vandriver

Kevin Irving wrote: »

Was this in Rathfarnham, Dublin area by any chance? I paid 124.x (probably.9) about 1km after the light came on and put in €20. I did the same motorway journey today, at the same speed as I do every week, and the light was on before I even made it to Galway today.

Completely unscientific as I didn't brim it(as I have been doing so far in 2015), but since the price has dropped recently, €40 has done me for the week. 2x Dublin-Galway runs, and driving 2km to work each day.

Off the top of my head:
Ambient temperature
Wind
Traffic conditions
Load carried
A/C on/off
Are just a few of the variables.

Alun

StereoSound wrote: »

As an average motorist I'm gaging my fuel fill by my fuel gauge as most of us do.

I don't and never have. All a fuel gauge is any good for is seeing if you're either full, or getting close to empty. Anything in between is pure guesswork.

Just fill the tank up to the brim, none of this "putting in €20" stuff, and zero the trip meter. Next time, do the same, note down how many litres went in and how many km you've done in the meantime. Rinse and repeat. Anything else is pretty meaningless. Engines run on litres of fuel, not euros.

Alanstrainor

Alun wrote: »

I don't and never have. All a fuel gauge is any good for is seeing if you're either full, or getting close to empty. Anything in between is pure guesswork.

Just fill the tank up to the brim, none of this "putting in €20" stuff, and zero the trip meter. Next time, do the same, note down how many litres went in and how many km you've done in the meantime. Rinse and repeat. Anything else is pretty meaningless. Engines run on litres of fuel, not euros.

And even then....just because you've covered less kms doesn't necessarily mean you got less fuel for your money. Temperature, style of driving etc etc will all affect your consumption.

StereoSound

LIGHTNING wrote: »

But your ignoring so many variables that your initial comparison is meaningless. Your accusing a petrol station of wrong doing without any decent evidence.

Surely there is bits I've missed out on since its not as someone pointed out a scientific approach. I've arroused 'suspicion' on a partial fill up on this occasion and wanted a general direction someone could point me to so I could read up on it. As a few have pointed out there may be other factors concerned such as a poorly calibrated fuel pump for example. If that's the case then an accuracy test performed by a body would allow for the incorrect measurment to be solved if that is the case.
Obviously I don't have any hard evidence of anything other then my personal experience from it. Even if it was deemed the pump was dispencing the wrong amount then it could have been a case where it was simply setup wrong. I would accept that as an explanation to.

biko

Do you have a jerry can? If so fill it to the mark and check.

Bandara

Can I suggest that all the fill a 1 litre bottle / jerrycan etc etc are pointless

Just report it to the NSAI, they will go out within a few days and test the site. Any genuine operator will have no issue with this, actually it's handy as its a free way to get calibration Certs as normally we have to pay about €800 for them

Allegedly 'some' operators get a friend to ring and report their own garages in order to get an inspection and save a fortune

kirving

vandriver wrote: »

Off the top of my head:
Ambient temperature
Wind
Traffic conditions
Load carried
A/C on/off
Are just a few of the variables.

I completely agree, but it was a motorway journey at 120kph on cruise control, same load, no traffic, ac off, wind about the same, but maybe maybe 3-4 degrees warmer today according to the external temp.

I usually wouldn't post on something so arbitrary, but the light was on with about 30km left to go today, whereas twice the volume of petrol has been doing me more than double that distance lately.

€20 @ 1.25 = 16L

180km until the light came on again is giving me 8.8/100km or so. Car reported it did 7.8l/100km for the journey, as it normally does.

I realise that there's margin for error, and I'll brim it and save my fuel usage with an OBD scanner .vs. actual as I have been doing, but today I do really think that the error is very high this time.

9935452

StereoSound wrote: »

Some of the local garages where I'm living are not convincing me they are dispensing the volume of fuel they should be. Today my local garage was advertising fuel at 124.9. I put in €20 and I didn't get as much for my €20 as I did in another garage the previous week which had fuel advertised at 1.28.

Another thing as well, my local garage has new pumps installed and I notice when I press the trigger on the pump to dispense I don't hear the fuel pump starting until the meter has already read 60 or 70 cents.. That really ticked me off and not sure why it happened but I'm avoiding that garage now from here on in.

Who would I report suspect garages to? I have no idea if there Is a body who test these garages on regular basis.

I assume with the new pumps the system is pressurised , when you pull the trigger it starts filling off the pressure in the system, when it drops the fuel pump kicks in.

Kevin Irving wrote: »

I completely agree, but it was a motorway journey at 120kph on cruise control, same load, no traffic, ac off, wind about the same, but maybe maybe 3-4 degrees warmer today according to the external temp.

I usually wouldn't post on something so arbitrary, but the light was on with about 30km left to go today, whereas twice the volume of petrol has been doing me more than double that distance lately.

€20 @ 1.25 = 16L

180km until the light came on again is giving me 8.8/100km or so. Car reported it did 7.8l/100km for the journey, as it normally does.

I realise that there's margin for error, and I'll brim it and save my fuel usage with an OBD scanner .vs. actual as I have been doing, but today I do really think that the error is very high this time.

I definately wouldnt go by when the lights come on, you hit a bump or park it up hill and the light can come on early. I always fill the car to the brim and normally let it run down to the light. It can be amazing the difference in litres when i fill just after the light comes on.

One other thing you might not be thinking is the other garage you are using , the pumps there might be calibrated the incorrect way and giving out more fuel

jprboy

Kevin Irving wrote: »

I completely agree, but it was a motorway journey at 120kph on cruise control, same load, no traffic, ac off, wind about the same, but maybe maybe 3-4 degrees warmer today according to the external temp.

I usually wouldn't post on something so arbitrary, but the light was on with about 30km left to go today, whereas twice the volume of petrol has been doing me more than double that distance lately.

€20 @ 1.25 = 16L

180km until the light came on again is giving me 8.8/100km or so. Car reported it did 7.8l/100km for the journey, as it normally does.

I realise that there's margin for error, and I'll brim it and save my fuel usage with an OBD scanner .vs. actual as I have been doing, but today I do really think that the error is very high this time.

Have you checked your tyre pressure?

Jesus.

StereoSound wrote: »

I notice when I press the trigger on the pump to dispense I don't hear the fuel pump starting until the meter has already read 60 or 70 cents.

I often notice that too now that you mention it

Jesus.

9935452 wrote: »

I assume with the new pumps the system is pressurised , when you pull the trigger it starts filling off the pressure in the system, when it drops the fuel pump kicks in.

That explains that then

jprboy

jprboy wrote: »

Have you checked your tyre pressure?

LIGHTNING wrote: »

Doesn't matter if he is running his car on 3 wheels. OP isn't using any sort of reproducible results.

My question wasn't directed to the OP but to another poster.