I have a 2007 Honda Civic EX 5 speed. It has 57 000 kms on it and I seem to be getting pretty bad gas mileage. With a complete fill up I barely get 450 kms of city and hwy driving. I don't drive it hard at all. Oil is changed regularly and air filter has been replaced.
that stuff is true.
when you are filling a tank the air inside is getting displaced by the liquid fuel coming in. the epa is starting to get real strict on evaporative emissions (emissions that come from fuel evaporating into the atmosphere) so gas pumps have a system that will recover these vapors as they are being pushed out of the fill neck.
when the temp rises in the gas tank the pressure goes up and some of the gas turns into vapor state. back in the day the gas cap was designed to relieve the pressure (along with the fuel vapors to be vented into the atmosphere)
now it is required that cars have a vapor recovery system. this is what the charcol canister or sometimes called evap canister is for. it stores the vapor and releases them into the intake manifold at a time the system determines as proper to be burned as fuel.
also if fuel in liquid state reaches this charcol canister the charcol pellets will get saturated and will not be able to store vapors anymore and this will cause the car to fail emissions during an inspection. this is why they say over filling can damage your evap system. you cannot just replace the pellets, you will need to replace anything that the fuel has damaged in order for the system to work properly again.
if you take an old car like from the 60's and left it in a garage it will give off more emissions just staying there (not running) than a modern car idling in the same place.
im doing a write up on emissions system and will be posting it in the technical chat section.
I have a 2007 Civic ex coupe as well and i'm only getting 400-450 km to a tank aswell! no clue why, it's manual and i shift very low, 3000 rpms is the highest i go, usually shift at 2500.. puzzled why i am getting such low mileage..
Its winter ppl! More fuel is required to achieve stoich in colder weather! Winter tires, longer warm up times all affect fuel economy. I went from 4.5 to 5.5L/100KM in the summer to 5.5 to 7.0L/100KM in the winter so its normal
I'm new to the forum, in fact i joined solely for the purpose of commenting to this specific post. I just bought a perfect condition 2007 EX Civic from a Honda dealership and it gets around 340-400 km/tank. everywhere i've looked has stated that i should be getting way more except for this forum. Is it specifically a 2007 ex civic problem, or have people with other years or trims of cars noticed the same thing? optimally i would like to find the cause and reverse it, because i bought the car for the gas mileage and so far its costing me $60 to fill for 350 km.