Hello Guys,

I am new here, this is my first post, I have tried the Search option and it seems all the low mileage problems were due to either a calculation mistake form the car owner, or a faulty gauge.

My problem with the low mileage is a real one I guess, last month I bought an imported a 2004 Civic EX with 69000miles on the Odo., according to carfax, car was first sold in North Carolina, from Stevenson Automotive Group and was serviced by them through out the vehicle history in USA www.stevensonauto.com , anyway I filled the tank, drove the car and at 62miles I refilled, it took 15Lit to full, then I did the test again, and at 120miles I refilled and it took 24Lit to full, this is equal to 18.7mpg, my wife drive the car, and its a combined city-highway trip, to school and back home, frankly, I did not do maintenance yet, I am going to do it this week, I am planning to change, spark plugs, air filter, fuel filter, the car has a mono injection system I guess, I have an OBDII scanner, and I can measure STFT and MTFT as well as LTFT, the car shows now faults at all, I wonder how to check if the Oxygen sensor is running right, also how to check the condition of the Cat.?

kind regards
Billy

 

If there is any thing wrong with Oxygen sensor is should give check engine light. maybe you have a gas leak?

 

Yea unless there is a check engine light your converter and O2 should be ok. I say do the tune up first and then measure your mileage afterwards and see what you get. You'd be amazed at the MPG gains you'll see with a simple tune up. Also remember to treat that gas pedal like an eggshell to help you squeeze all the MPG you can out of it.

 

Thanks guys, the throttle pedal is already treated like an eggshell, I will do the tune and I hope to see a better mileage.

anyway I will hook that OBDII diagnostic tool I have and check the reading for the fuel trim.

kind regards
Billy

 

A tune up will definitely help; I'm not sure it would explain the 18.7 mpg's however. Take a good look at the plugs when you replace them, and also take a good look at the condition of the cap/rotor, if they're in very poor condition it might help explain the abysmal mileage.

The cat would not affect your mileage unless it's clogged in some way. Your exhaust would sound pretty horrible if it was clogged. Your secondary sensor would likely throw an emissions code if your cat wasn't doing it's job though, but it won't adjust your AF ratio.

Could also think about running some BG44K through the system to clean the injectors.

 

is that like seafoam?

 

That, or something like Lucas injector cleaner?

 

You can run it through your gas tank, but unlike Seafoam you don't pour it in your crankcase, or suck it through a vacuum line.

It's a good quality product, pricey, but worth it. I've seen it at a few Honda dealerships. I believe they use a BG products to clean fuel systems in the service depts as well.