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Originally Posted by DerAlte With all due respect, what has the above got to do with right observations and inference? Probability of human error, whether your friend's or any other person's, would remain the same, no? |
1) That was a passing statement after the statement confirming that this was done correctly. And the checking was done a 2nd time because he was surprised by the difference in mileage shown the first time. Extra care was taken during the second time.
2) In the place where I work, when we deal with customers, we push in questions based on the knowledge level and experience of the customer involved. And this has served us well in the last 10 years. It's not that we don't check everything, but the focus will be different depending on the kind of customers involved. Questions like "did we really check the trip average mileage ? " doesn't make sense to the person involved. So, thought of helping you with the knowledge level. If you don't believe in this, you can ignore it. This is not the important point here.
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Originally Posted by DerAlte In any discussion one has to hold at least one thing as 'trusted and true', otherwise all inferences are clouded. I hold the MID as trusted - if it is working constantly, not intermittently or incompletely. You hold the rather approximate 'human' method as trusted, and mistrust the MID method. The difference essentially will come due to what I wrote in italics, as well as the gas station metering and 'full to the brim' sensing. |
Let's assume
A --> Error on MID
B --> Meter calibration error of fuel station
C --> Error on tank full filling
Now, consider the following points.
1) The odomoter reading made sense with regards to amount of distance covered. ( this was his regular route. )
2) The fuel was re-filled after the fuel gauge showed almost empty
3) On both ocassions, different fuel stations were used.
We can take any of the above as the only error that could happen. Whichever logic we use,
C is almost impossible to cause a discrepancy of 40% in mileage.
With regards to B, if it's causing 12 liter discrepancy for a 40 liter re-fill, then petrol pumps are running a scam. If this is the case, I'll ensure that media attention is directed in that path atleast in my state.
By all logic, A is the most likely reason for the error because running such a scam in a state like Kerala is suicidal for whichever people involved. And in my personal experience of 10 years of re-filling in the pumps involved, it was never logically so wrong. Yes, there has been differences like 2 liters or so. But, even that was in rarest of rare scenarios.
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Originally Posted by DerAlte If whatever has been observed by your friend was how it is, perhaps it is better that he gets the MID checked at the A.S.S. for interference. Not an easy thing to do, since it requires careful and accurate monitoring. The issue could be with CAN bus going to the MID unit. Checking the gas station's metering calibration would also be a wise step - if feasible. Reputations usually make us assume wrongly. |
I'll be checking the calibration. But, for a 40% error to go unnoticed by the customers, I'm not sure about that.
Anyway, we'll also be taking the car to the service center as well.
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Originally Posted by DerAlte It is wrong to blame the manufacturers for problems. With cars sold in multiples of 100K around the world. Either there would be a public outcry for a failure-prone component (happens occasionally, leads to 'recall'), or quite likely there must be a simple fault in the few cases where a component has malfunctioned, not a design fault. |
1) Hyundai and KIA was caught cheating customers in mileage calculations. And for some reason, they themselves couldn't find it till the environmental protection agency ( EPA ) found it out. Whether or not the error is intentional or not no one can guess. But, what is interesting is when these manufacturers makes errors on mileage calculation, it's always in the more optimistic range for some reason.
2) Every user who has posted in this thread has reported lower mileage in real life ( based on the amount of money spent ) than what is shown on the MID.
It's difficult not to blame the manufacturers after seeing such instances.
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Originally Posted by arindambasu13 THe MID on my 2012 VVT Swift shows an average fuel consumption of 15.8 kmpl. In real time, with 100% city bumper to bumper driving, the FE is about 12.5-13.5. |
Another case, where the mileage is offset by 20% this time. I hope, all the fuel pumps in India are not running a scam.
It's either the fuel pump or the car manufacturers. Fuel pump's case is easier to rule out. I'll check that out when I get time.
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Originally Posted by Jeroen In general MID are calibrated, just like mileometer to err on the safe side of cautious.
Manufacturers don't want to get into trouble of you getting a speeding fine, whilst you thought you were on the speed limit. Or to run out of fuel before the MID tells you so. |
1) What about the odo meter ? Is that too calibrated on the same side ? If that's the case, then the same error should appear in both the MID as well as the manual calculation. So, that negates the effect of the calibration.
2) If the odometer reading is not calibrated so, why can't the MID depend on the odometer reading for average mileage calculation ?
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Originally Posted by Jeroen Without getting to technical but the fuel used figures tend to get more accurate as you use more. To put it differently. If you fill up your tank and then drive 100 kilometer and check actual fuel against MID reading it's be less accurate as when you drive 500 kilometer and check actual fuel used against MID reading.
Jeroen |
In this case, it was a "use more" scenario, because the amount of fuel re-filled was 40 plus liters. But, was still left with a 40% discrepancy.