Mileage oddities

[smorris_12]

So I've just got back from a 2 day jaunt to the Midlands and have racked up about 300 miles. The night before I left, just as I got home, the odometer ticked over 98,000 and, with a long trip coming up, I reset the trip counter. Fast forward to getting back tonight and...




... the trip counter is 1.5 miles adrift of the odo which I would never have expected. It's not a number of starts thing (which I could sort of understand) but just pro rata to distance.

I wonder how such a bug could get thru development? It doesn't really matter but this is annoying as I really fancy resetting the trip at 98333 to give me a shot of 098765 432.1 showing on the dash!

 

[Rockhopper]

Might be due to the odometer only reading to whole numbers whilst the trip reads to tenths of a mile. So when you set the trip the odometer could have actually been reading 98,000.9 but only displayed 98,000. Or something like that!

 

[smorris_12]

Nope, not a rounding error. The odo was reset at about 98000.02. For the first few miles I caught the trip counter ticking over within a few seconds. A bit later I thought it seemed worse. And a lot later it was 0.5 miles out!

 

[enuff_zed]

Soon 300 miles there is a difference of 1.5 miles.that’s roughly 5 miles in every thousand. Which is 500 miles in 100,000. Yes it’s a discrepancy but if I bought a car with 100k on the clock and later on found it was 500 out??
Not much to worry about really

 

[smorris_12]

Oh I'm not worried, just perplexed. I assume the odo to be the sacrosanct one anyway but I just can't understand what is going on in the system. The dash just counts pulses and turns it into a number using the programmed fiddle factor.

Joys of being an engineer with an empty evening!