Fuel pumps +/- 0.3%

http://www.measurement.gov.au/Publications...%20LPG.pdf


More measurements:
http://www.measurement.gov.au/TRADEMEASURE...dFuel.aspx


It may be better to fill up a 10 or 20 litre petrol container at each pump, allowing some tolerance for container expansion, rather than relying on the car's measurement. Procrastination, mankind's greatest labour saving device!

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Dartman the one wrote:

How are you measuring brim to brim, I suggest you could well be 1.5 litres out depending on patience I have managed to fill the tank with over 75litres and I was still not sure it was full.

As long as you are filling to the same level approximately between fills then the test is still valid. The tank does not have to be full. For this to be more reliable, you would always need to use the same pump as the auto stop calibration may vary pump to pump which would affect the fill level.

I was always using the same pump (see first 3 fills) and assuming the auto stop cal didn't vary much over 3 weeks it is evident the amount appearing to be delivered is going up for a similar mileage. The resulting calcs then put the MPG miles away from the OBC.

I always fill to the auto stop, then wait about 4 secs, then fill to stop again. I then repeat twice and then leave. This makes it repeatable.

Thinking about it, I will have to wait until I top up again next week at the new pump as the auto stop cal may be different between the old pump and new, and that would affect the fill level and calculation.

Having said the above, there are natural variances that occur all the time so that is to be expected but not at the level I was seeing between top ups.

From another thread:

Lightwater wrote:

I have only filled the car 10 times so it's not really a large enough sample. The car fuel consumption figures range from (maximum range) -5.1% to +3.8% as compared to the petrol station receipts. The car to date has shown an average over estimation of 0.4%

So, just topped up again to the 'same' level on the same new pump. The calculations reported 32.1mpg which is within 2.5% of the OBC (32.9mpg). Last weeks fill was a bit closer but what this indicates is that with this new pump, the brim/brim method pretty much agrees with the OBC. This is good.

Conclusion is that the first pump I was using was under delivering and I need to let them know.

Reminds me of the Romanian I met in Bulgaria. He was on his way back to France but intended to go back via a Romanian petrol station to ask why their pump had filled his car with about 50% more diesel than the tank would hold the previous week! (Very nice chap - sorted out a currency problem at the border for me). Ex AA Series III LWB Safari - Gone
300TDi Disco (bought new - terrible car) sent back after 18 months
Freelander 1 Estate - leased, given back at end of lease
200TDi Disco (bought from a mate with 100,000 on the clock) - Gone
Disco 2 TD5 - sold and exported to France
FR2 TD4 GS - Gone
FR2 SD4 HSE - Now changed for a DS
New model ex-demo Evoque S 180 in white
Unable to order a new DS, so gave up. Now have a Volvo S90 Recharge.