Hello Everyone,

I Got my car in the summer around July and noticed almost right away the poor gas mileage. I searched this forum and tried out some of the recommendations as well as searched the internet. Any more ideas would be great!

Details:

2007 Honda fit Sport Automatic around 100km
I get on average around 340-400km per tank. The best I ever got was 402km and it was 99% highway (long road trip). On average though its around 340-360km per tank.

(Thats about 211 miles to 223 miles per tank!)

I measured for several months and I did notice that I always filled up around 32L which is close to 9L left. (Thats 2.3 gallons on the 10.8 gallon tank).

Work been done:

Checked/Changed tires (air is fine)
Sparks/Coils changed
Used some gas cleaner in hopes that would work (did nothing)
valve clearance check
filters checked

my mechanic did say that my cat is showing some signs as it remained hot for awhile while working on my car. So it could be clogged a little but not sure if this would be the result of horrible gas mileage. I do also notice this car has 0 power and 0 pickup. I know its an under powered car but I mean I shouldn't have to slam my foot to the floor for it just to considering moving, I'm not sure if this normal for the fit or if it is the result of something else.

Thanks!

 

Yeah, there's something wrong with this. I just got 650km on a tank of gas on a highway run where I wasn't trying to drive especially economically. Sorry that I cannot suggest any possible fixes.

 

Remove the cat at home and drive it around the block. Problem solved? Replace cat.

Not resolved, continue troubleshooting.

 

Per your data you're getting about 27mpg. Depending on how you drive that could be low or not. If as you state you frequently are slamming your gas pedal to the floor at takeoff then I'd say the mpg you're getting is about right.

_

 

Well I think we found your problem.. adjust to the way the car needs to be driven and you'll find mileage more acceptable. Whipping the mule harder has diminishing returns.

But as noted ~27mpg is still within acceptable range.

 

Sorry, to clarify: The having to press the pedal hard was more of a symptom as I think they car shouldn't have to do this. I generally don't;I drive it pretty normal (I mean its a honda fit?). Its just when I need to pass someone on the highway going 80km I find it takes the car a lot of effort to get that extra 5km to pass them. I'm not sure if its 'normal' for a honda fit to have very poor acceleration or if this is a symptom of something else.

As for driving habits its all pointless I've driven the granny driving to the just not caring driving with almost the exact same results, it may vary by 10-20km in the end.

As for the removing the cat how safe is it to drive around without it for almost a tank of gas? It would be hard to determine just driving around the block if my problem has gone away, I would think I would need to drive some period of time to determine the millage.

 

First, to measure yiour Km/L you must stop using Km per tank. Just not accurate enough to know.
Divide the km driven since last fill up, all the way to full, and divide by the number of litres you put in the tank.
Generalyy, fill on automatic cutoff then when it cuts off finish refilling to the next whole EU, whatever. You'll need to do several times to get a good average. If you're getting about 13 Km/L you're about average. If its no more than 10 or 11 KM/L you're either driving most uneconomically or your Fit has a problem with plugged exhaust, not just the cat tho its my first choice at your mileage, plugged air intake or bad tune up.
good luck.

 

You will feel a big difference right away if your exhaust is plugged up, you won't need to drive 300 miles and get gas mileage results. I am doubtful that the honeycomb in the cat failed but it's possible, i've seen it happen on newer cars than yours (although they were all driven hard, maybe you do too?)

I don't recommend driving around with the exhaust dumping in the middle of the car for any extended length of time... if you do, keep the windows rolled down

 

Thanks for the idea ...This car was bought used and I'm not sure how the previous owner took care of it, but its possible they treated it poorly.

 

You won't have to completely remove the cat; just disconnect the front end and support it out of line with the exhaust. Like it said, if its plugged you'll know virtually instantly.