I refuled, I then reset trip A and B before driving off. I circled around from "start" to A then to B and back to start, they all read different. the start and B trip reading were close, about 1 or 2 mpg difference but A trip was off by 5 mpg. I figured they would be pretty much the same reading but why A was so much off was perplexing. I arrived at gym about 5 miles away, the difference from A to B and start was down to 4 mpg. why so much disparity, shouldn't they all not be the same or very close to it? I had originally posted this in the 3 forum and had just realized it and copied it here. a mod may delete the one in the 3 forum.
not at all. the only way to get similar readings would be to do the exact same trip, in the same weather, and the same driving conditions. almost impossible outside a lab, but you should be able to get within an mpg or two.
From start is literally that, from when you turn the key. Depending on how long you let the car sit in the place before resetting trip A and B, that could be a good bit of electricity/time. The only way to get all three synched up is to power the car into AUX mode, reset the trips, then power the car on.
G'day priustexasbob, I may not understand your post correctly but..... ..did trip A and trip B read the same distance (km or miles)? You re-zeroed them at the same time? My understanding is that A and B read/estimate the fuel consumption/mileage for the total A distance and total B distance respectively. Only ODO gives a display of just the current trip (or from engines start to engines stop, to be exact), if A and B are not re-zeroed at that trip's start-up. So if A km/miles does not equal B km/miles, there is little reason to expect the consumption for A and B to be identical, particularly the bigger the distance difference between A and B for low values of A and B. The further I go, the closer A and B consumptions become, but for just a few km/miles, these can be quite different due to the high consumption in the first few km/miles. Local conditions do vary, as does my foot on the accelerator, so I find here that the same short trip can be quite different, especially from a 'cold' start. Have you repeated your test several times to reproduce your puzzling result? To come up with a consistent set of averages for A and B? Puzzling. David S.
yes David, the mileage was exactly the same. I reset (zeroed) everything after starting and within a few seconds I drove away. I will redo this again once I refuel.
The calculations provided by the car are estimates only. These are not precision instruments. You have uncovered the fact that the calculations for the two trip meters must not be using the same subroutines to calculate mileage.
It baffled me there, and here, lol. Is there any chance you reword that. I was a draftsman, and then a checker for a few decades, and I pride myself on being able to decipher most anything, but I'm stumped as to what you've done. Maybe a diagram??
G'day pruistexasbob, Unless you're keeping a fuel log on A or B (I'm guilty on my B ), you could do a re-test any convenient time by again re-setting your A & B, or even for each coming trip. This would quickly generate more data on this oddity. Maybe some others could do the same test on their 'c's and report for a comparison? David S.
after 220 miles, they have synced up. I will refuel tomorrow and redo this. sorry for the Kornfusion, math was my strong suit, not English. (diagramming sentences may as well have been done in Klingon as incomprehensible as that was and is to me LOL)
Disconnected my 12v battery to do rea/r brake caliper pin relube at the meet up couple weeks ago and driven it everyday. Both trip a and b a/re stillexactly the same, this thread came to mind when I was just about to reset A for an extended trip So if you want to truely reset & sync both trips back to 0s, unplug 12v battery and plug it back.
I too have doubts about the accuracy of 'trip meters' please read this thread I posted Low mileage after a lot of idling with ac on all the time | PriusChat
