Displayed FE wrong??

2007HCHOttawa · #1 04-16-2007, 02:45 PM

I recently purchased a 2007 Honda Civic Hybrid here in Ottawa, Canada. I am still running on the first (dealer-supplied) tank of gas. Earlier today, the Low Fuel Indicator came on with 2 bars left on the Fuel level display. Odometer reading at that time was 717 kms (445.5 miles). Tripmeter A (which is going to stay my lifetime tripmeter for now atleast) says I'm getting 5.4 l/100 kms (43.5 mpg). But somehow the math doesnt add up.

Fuel tank size = 50 litres (approx as per manual)
Fuel remaining when light comes on = 4 litres approx (Manual says 3.5 litres remain between when light comes on and display bars drop to 0 or E. plus there about a half litre in reserve after it hits E)
So Fuel consumed so far = 50 - 4 = 46 litres approx = 12.15 US gallons - (between when it was topped up and today when the low fuel indicator came on)
Based on this I am getting a "calculated" FE of about 6.4 litres / 100 kms (36.75 mpg). But my tripmeter A still says 5.4.

So possible causes ...
1. displayed FE is way way wrong (I've read that the displayed FE can have upto a 10% error but most posts indicate that actual calculated FE is "better". So this scenario would mean that my car's computer / fuel calculation system is wrong.
2. Dealer didn't fully fuel up my car initially. Not sure why they would do this. But this seems to make the most sense. This would explain why the displayed lifetime FE is not aligned with the tank FE.
3. Honda's manual is wrong and the tank sizes indicated are not correct. Again I'd be really surprised if this were the case.

I am not really too concerned about the FE itself (the car is still breaking in and its been cold (around 0 Celcius) and I'm no expert hypermiler). Its just the inconsistency that's bugging me. I'm wondering if anyone else has seen anything like this? I will have my first fillup tonight and i'll be using Tripmeter B to measure tank FEs but I don't think I'll have an answer to my confusion till my next fillup. The only way I can know for sure what FE I am getting is if I compare my own fill ups and that might tell me which of the above causes applies in my case.