How accurate are servo pumps?

[p38arover]

I filled the D1 up with diesel yesterday as the low fuel light had come on.

According to the owner's manual, the car has a fuel capacity of 89 litres.

At the Woolworths Caltex where I fuelled up, I got 90 litres into the tank. Is that how they recoup the cost of the 20 cents/litre shopper docket? :o

Do you think Woolworths will believe me if I complain or is the Disco tank actually more than 89 litres? Admittedly I filled it up to near the top of the filler neck. That'd take a few more litres.

[EchiDna]

I can find out the real truth if you like... my company has a calibration division that works on the meters used in fuel bowsers (sp?) as well as those measuring the volume from bulk tanks to the truck tanks to the store tanks... anyway, I'm pretty sure they are +/- better than 0.5% and not much better, but I'll find out :)

[Lotz-A-Landies]

Ron

It used to be that "Weights and Standards" a NSW Government agency would go around and randomly check servos using a calibrated vessel of I think 10 litres. Weights and Standards is now under the domain of the Office of Fair Trading and the Standards Laboratory at Lindfield the accredited body.

In this day and age the checking has probably been deregulated.

Are there any servo people out there who may know more.

Diana

[PhilipA]

I complained to NSW Fair Trading about a certain servo north of Sydney for the same reason ie more than the tank held, and they went out and checked a few days later.
They rang me back saying they found the pumps accurate, but I still wonder if the servo had a "100Kmh" switch like the truckies have.
The servo was 5cents cheaper than anyone else.
Regards Philip A

[p38arover]

I also complained (to the servo) about another Woolies Caltex servo. I had been running a particular LPG tank for a couple of years and I alway ran it "dry". I consistently got 54 litres in to it (+/- 0.5 litre). Yet at this Woollies servo on Epping Rd, I got significantly more (about 6 litres). They denied their pump could be faulty.

[p38arover]

Ron

It used to be that "Weights and Standards" a NSW Government agency would go around and randomly check servos using a calibrated vessel of I think 10 litres. Weights and Standards is now under the domain of the Office of Fair Trading and the Standards Laboratory at Lindfield the accredited body.

In this day and age the checking has probably been deregulated.

Are there any servo people out there who may know more.

Diana

Yes, one used to see them around a fair bit. I haven't seen them in years.

[Phoenix]

Are you considering the ammount of fuel in the filler neck, that can hold a bit and (I think) is not included in the tank volume.

[d@rk51d3]

I also complained (to the servo) about another Woolies Caltex servo. I had been running a particular LPG tank for a couple of years and I alway ran it "dry". I consistently got 54 litres in to it (+/- 0.5 litre). Yet at this Woollies servo on Epping Rd, I got significantly more (about 6 litres). They denied their pump could be faulty.


Had a similar experience driving from Adelaide to Darwin and back, last year.

Had a few stops where the tank miraculously took about 10 litres more than it was capable of.:mad:

[p38arover]

Are you considering the amount of fuel in the filler neck, that can hold a bit and (I think) is not included in the tank volume.

Yep, I considered that (see first post). It doesn't apply to LPG as there is a float operated shut-off valve on the filler port in the tank.

[crump]

I always wonder about whats left in the actual hose, especially with HI-Flo pumps.I've paid for it but its not in my tank unless I want to perform gymnastics with the hose to get the last bit out.By the way, does anyone do this???

[Offender90]

A "tips on filling fuel in your vehicles" pdf was circulated by someone at my work recently (attached) Could it explain the observed discrepencies (if accurate)? Don't know, 10 litres is a bit much to disappear, maybe some of it overflowed? No guarantees on accuracy by the way, but thought I'd throw it out for comment from those in the industry. Or perhaps anyone with access to reliable info... EchiDna?

Cheers

[p38arover]

I always wonder about whats left in the actual hose, especially with HI-Flo pumps.I've paid for it but its not in my tank unless I want to perform gymnastics with the hose to get the last bit out.By the way, does anyone do this???

Yes, but it only works when you have put in a set amount, e.g., $50 worth. Then you can hold the pump nozzle handle open whilst you manipulate the hose.

[Pedro_The_Swift]

I always wonder about whats left in the actual hose, especially with HI-Flo pumps.I've paid for it but its not in my tank unless I want to perform gymnastics with the hose to get the last bit out.By the way, does anyone do this???

you do get the free bit left from the guy before---

[d@rk51d3]

Without trying to make it look obvious........ yes.:D

[B92 8NW]

I always wonder about whats left in the actual hose, especially with HI-Flo pumps.I've paid for it but its not in my tank unless I want to perform gymnastics with the hose to get the last bit out.By the way, does anyone do this???

I don't think this is a problem as the hose would probably be full when you pick the thing up to stick in the tank. Would it not also be impossible to "drain the hose" because in squeezing the trigger, its only going to pump more?

Maybe, and I might try this, you could drain the contents of the hose if you placed your hand on the cradle thereby manually shutting the pump off and simultaneously squeezing the handle.

[paulthepilot_5]

I don't think this is a problem as the hose would probably be full when you pick the thing up to stick in the tank. Would it not also be impossible to "drain the hose" because in squeezing the trigger, its only going to pump more?

Maybe, and I might try this, you could drain the contents of the hose if you placed your hand on the cradle thereby manually shutting the pump off and simultaneously squeezing the handle.

I like this idea :) I reckon i i could just about fill my bike with the fuel left in the hose :twisted:

[p38arover]

I like this idea :) I reckon i i could just about fill my bike with the fuel left in the hose :twisted:

Wheeling it from pump to pump might be a bit obvious! :p

[hodgo]

I had the same problem a couple of years ago at a Caltex in Beenleigh Qld. More fuel than the tank could hold according to Ford's spec's
I reported the matter to the weights and measure people who did a check and in formed me the pumps were correct. I did not except this finding and they proved to me it was my vehicle that was at fault .
Not only hadt the plastic fuel tank had saged between the two straps that held it in place but the hole fuel tank had changed shape which had increased the compacity by about 7 liters.

Hodgo

[p38arover]

Not only had the plastic fuel tank had sagged between the two straps that held it in place but the whole fuel tank had changed shape which had increased the capacity by about 7 litres.


I suppose it's possible that's what has happened with our Disco.

[EchiDna]

okay well here is the deal for service station meters - in the past (as surmised above) the weights and measures blokes used to bring out a prover tank (a proven volume tank) which measures the exact amount (+/- about 50mls) for 10 litres or gallons if you go far enough back :) and measure what they get from the bowser. These days a primary meter (one calibrated with a prover tank) is used onsite to measure the accuracy of the bowser. These primary meters are 0.02% accurate, while the bowser itself must be 0.05% accorate or better to be in use.... in terms of variation in volume - higher temperature reduces the density of the fuel, going from a cool underground tank to a hot in vehicle tank can cause less to fit, with the reverse in winter... warm underground, cold above ground, more (by volume) in the tank. However fuels are not bought on volume, they are bought on energy content (e.g. RON 92, 95, 98 etc...), so if you buy your fuel on a hot day, expect to get a bit less bang for your buck as the fuel temp in the tank preceeding the meter will be hotter and hence less dense.

Of course none of this takes into account the variation in the scruples (sp?) of the petrol station owner in the first place who might just have a switch under the counter for just such circumstances.

[hodgo]

I like this idea :) I reckon i i could just about fill my bike with the fuel left in the hose :twisted:

____________________________________

When I first owned a car, this practise was very common with the type of bowser we had in those days , shut the pump off them drain the hose Have not tried it of late , dont think it would work with the new bowsers/ hose nozzels

Hodgo

[scarry]

hi
dont know about the d1, but the d2.....you can often put at least about 4 to 5 litres more in it after the pump clicks off.have dribbled 95 litres in mine& it was not empty
also pump flow calibration....is it done at full flow or at different flows?

if you dribble fuel in,particularly diesel,it can get frothy.will this affect the calibration of the pump?

cheers

[EchiDna]

....also pump flow calibration....is it done at full flow or at different flows?

if you dribble fuel in,particularly diesel,it can get frothy.will this affect the calibration of the pump?

cheers

full flow, looped back to the main tank and gas/air/bubbles in the line don't affect it...

[CraigE]

I also complained (to the servo) about another Woolies Caltex servo. I had been running a particular LPG tank for a couple of years and I alway ran it "dry". I consistently got 54 litres in to it (+/- 0.5 litre). Yet at this Woollies servo on Epping Rd, I got significantly more (about 6 litres). They denied their pump could be faulty.

Ron,
With lpg it all depends on the day and weather. I know in my Rangie on a hot day I would get 100-105 litres in from bone dry. On a freezing cold morning at 0430 often would get 120 litres in. There is also some expansion in lpg itself so on a hot day you may get a little less than you think and on a cold day a bit more. Not much but a bit. I know on a cold morning if I filled up and it was going to be a warm day I would only fill until it was one bar under full and when I would come out in the arvo after sitting in the sun would show full. Same happens with petrol to a lesser degree due to specific gravity and expansion rates. Normally within guidelines, so a pump may in fact be giving you the right volume, but when it cools at night may be a bit less.;)

[p38arover]

BUt it's going in as a liquid, not a gas. The shut off is a float valve, not a pressure valve. (I know 'cos I've pulled them out. If you adjust the float you can get more LPG in. Seriously, I was once told that by an LPG fitter. I haven't done it.)

[Lotz-A-Landies]

Ron,
With lpg it all depends on the day and weather. I know in my Rangie on a hot day I would get 100-105 litres in from bone dry. On a freezing cold morning at 0430 often would get 120 litres in. g in the sun would show full. Same happens with petrol to a lesser degree due to specific gravity and expansion rates.....
Yes never buy LPG from a servo with an above ground tank on a hot day, you get less bang for your buck.

Petrol expanding, isn't that why servos try to get their deliveries at night so they get what they are paying for?

Diana

[Basil135]

hi
dont know about the d1, but the d2.....you can often put at least about 4 to 5 litres more in it after the pump clicks off.have dribbled 95 litres in mine.

cheers

So, at least I am not the only one.

Same thing happened to me...:cool:

[Utemad]

From memory in our F250s you could dribble fill another 13L or so after it clicked off. Think they had a 120L tank.

In my Disco1 with LPG manifold floor tank I can only usually fit 45-47L when it is totally empty. Sometimes 55L though. I thought it was a 55L useable tank. Never taken any notice of temp etc when it happens but it is annoying considering how small the tank is to begin with.
If it does only get 45-47L it drops from 4 lights (max lights) to 3 lights pretty quickly so obviously not full. I suspect the float shut off is faulty but I'm just guessing.

[scarry]

If you adjust the float you can get more LPG in. Seriously, I was once told that by an LPG fitter. I haven't done it.)

i wouldnt do this as on a hot day the pressure relief on the tank may go off:p

now that would be exciting:D:D:eek:

[Gaz_Series6202]

Also with the LPG filling, Barametric pressure(Altitude wise) comes into effect, in my granfathers 110" He has a 90L Tank and up in the moutains we can get 100L in it. More on a realy cold day.

[lewy]

so with the expansion of fuel because of heat would that then mean if a road train loaded in adelaide by the time he arrived in say alice springs the truck will have a significantly larger volume on board to sell to the fuel station.who makes the profit

[CraigE]

BUt it's going in as a liquid, not a gas. The shut off is a float valve, not a pressure valve. (I know 'cos I've pulled them out. If you adjust the float you can get more LPG in. Seriously, I was once told that by an LPG fitter. I haven't done it.)
My FIL was Kleenheat gas depot manager and knows heaps about this stuff. You can adjust the float, though this changes the setup, causes venting due to expansion of lpg when in the car tank and is illegal. While it is liquid, temp still plays a big part with lpg as it expands and contracts a lot more than most other liquids.
I have had 4 cars with lpg now and they all varied on filling amounts depending on ambient temperature. Its also not advisable to fill an lpg tank right up on a scorcher of a day although a bit safer than a petrol vehicle as lpg systems have vent devices and it vents as a gas not a liquid. Unfortuanately as most tanks are in the back of a car they vent inside the car and can be dangerous if an ignition source is present. I changed the vent / purge valve to a hose set up and ran it outside the car away from the exhaust.
Cheers
Craig

[CraigE]

so with the expansion of fuel because of heat would that then mean if a road train loaded in adelaide by the time he arrived in say alice springs the truck will have a significantly larger volume on board to sell to the fuel station.who makes the profit
Fuel delivery like this works on SG (specific gravity) not just volume. It also is calculated when filled at a certain temp / volume.

[p38arover]

Unfortuanately as most tanks are in the back of a car they vent inside the car and can be dangerous if an ignition source is present. I changed the vent / purge valve to a hose set up and ran it outside the car away from the exhaust.

In theory, they are vented to the outside world by a tube which also carries the wiring, fill, and supply lines. They should never vent inside.

[Utemad]

In theory, they are vented to the outside world by a tube which also carries the wiring, fill, and supply lines. They should never vent inside.

That is how mine is set up. Which is one of the reasons there is a sticker on the sealed cover saying that the cover should be in place at all times or something like that. Also why the black tubing is much larger than it needs to be if it was only to route the wiring and pipes I imagine.

[loanrangie]

I read a funny story years ago where a guy borrowed a mates charger and stopped at a servo to fill it back up with lpg before returning it, he stood there for ages waiting for the afl to shut off the pump . Well after filling with more lpg than he thought possible he decided to stop and only after smelling a strong gas smell realised that all the gas had escaped. Turned out that the owner removed the lpg tank to have it re tested or something and he was just filling the boot with lpg !

[p38arover]

While it is liquid, temp still plays a big part with lpg as it expands and contracts a lot more than most other liquids.

I would have expected fuel delivery pumps to have temperature volume compensators.

[CraigE]

I would have expected fuel delivery pumps to have temperature volume compensators.
And I believe they do of sorts, but when cold and I am talking 0 deg c or below you can fit more into a tank. A lot of it will be to do with the temp extremes in the area. In Kal / Kambalda we could have -2 deg c overnight at 0400-0430 when I would fill up on the way to work and get to mid to high 20s. I got caught a couple of times coming out to smell gas venting. So learnt not to fill it right up unless I was driving into Kal for work 50kms as oppossed to 2kms from servo when in Kambalda roster on (where I lived).
It not a huge amount but on cold mornings I could always get more lpg in the tanks. Great when heading to Perth or something.
As for the vents you are right they are supposed to have a vent tube, but I have seen many without them, bought a car that did not have one and most are damaged or blocked. They are generally cheap tubing that does not last and deteriorates and damages easy. I replaced mine with better quality fuel grade hose and a filter so they could not get blocked.

[martinozcmax]

I had exactly the same problem with a servo on the freeway from Geelong to Melbourne. Melbourne bound side. I filled up and the tank took several litres more than anytime I had previously filled it on empty. I do track my litres per k's travelled. Stopped using them. By the way my 93 Disco Tdi on diesel seems to have a 60 litre tank as I never get more than that in it.

FYI the states had a scandal a few years ago whereby the servo's had a chip installed that gave exactly 10 litres when that was selected however gave short filling on random fill ups. Not a co-incidence was that weights and measures always filled up 10 litres or 2 gallons or somesuch here and over there. Crooks aren't always dumb, though they did get caught in the end.

Regards


Martin