So I test drove a 2008 Honda Fit Sport and was instantly enamored. I had been driving a Prius C the past three years and love the quick acceleration of the electric drive, and that there just isn't enough under the hood for me to catch a speeding ticket. The Fit Sport is fun to drive, and just big enough to camp in and haul various equipment.

After running around Southern California looking for one in decent shape with decent mileage I got one from a private used car dealer in OC.

Most of the issues I found have been cleaned up, but I'm still getting less than 25 mpg, more towards 20, when driving around San Diego (which may simply be all the hills and street driving), and 30 highway.

What was done after purchase:
Ran Royal Purple fuel cleaner through
Replaced brake fluid
Replaced AT fluid
Replaced Oil and filter
Replaced radiator fluid
Replaced battery (which was nearly dead)
Replaced sparks and coils after they misfired a few blocks away from the dealer (it ran fine a week before when I test drove it)
Installed splash guards under engine and in front of front wheels (they were missing)

I also noticed that the car has been repainted. The mechanic I asked to inspect it before purchase wondered if it had been in an accident that wasn't reported to Carfax given the paint job and missing plastic on the under side. Various pieces inside don't quite fit together as well (such as the driver side arm rest, and a few floor cover pieces along door jams).

But with all this, it's still fun to drive and seems like it just needs some love as it wasn't cared for. I bought it just under 90k miles, now reaching towards 100k.

So my questions are if anyone has any ideas on further diagnosing what may be killing the MPG other than age/abuse/incline driving around San Diego. And secondly, what I should replace or inspect to ensure I can get another 100k (hoping more) out of this awesome little car.

 

I was never a big believer in fuel injector cleaners. Maybe you should send them out and get them professionally cleaned and flow tested. Maybe a good valve adjustment will help too.

 

are you also running Royal Purple engine oil? I found mpg losses using it.

 

I am though before the new oil and fuel cleaner I was barely getting 180 miles on a full tank. Since my mechanic no longer accepts outside oil/filters I'll be going with more generic brands next change. I did get 0W to try it out, not sure if sticking to recommended 5W will affect MPG

 

Just stick with what honda recommended, 5w20. I personally use pennzoil platinum on my fit and s2000. Royal purple and mobil are frowned upon in the s2000 community because they tend to burn oil alot quicker then other oils. You should not be getting 180 miles each fill up. I get 300 miles mixed highway and city/traffic. Like I mentioned earlier, professional cleaning for injectors, valve adjustment and maybe a new front primary o2 sensor. Any check lights on?

 

No check lights showing. Highway I get just short of 300 a tank. When I drive just city it's closer to 200-230. Next oil change I'll get the cleaning and adjustments done, I probably should have earlier but it needed so much work at tbe start that I didn't want to spend anymore until I was sure I hadn't purchased a lemon. It also needed a new ball joint in the front right and a sway bar, and the radiator fluid was really low when we drained before replacing.

Anything else I should do to make sure I'm in track to get to 200k? I also saw debates about replacing the AT fluid with each oil change to save having to do a full flush all at once. The dealer did use a hose to suck the old fluid out rather tha ln a proper drain, so I had a drain and replace done with the last oil change just in case they contaminated somehow.

 

I'd continue to use a fuel cleaner (or a Top Tier fuel) for a while. Those cleaners don't work overnight.

Once fully warmed up, I'd run it to redline once or twice a tank, for a while. The increased injector duty-cycle helps clean them out, and IT'S FUN.

BTW I'm hoping your MPG figures in the title reflect several gas tanks' worth of fuel? One thing I tell folks is, fill up before a trip of 100 - 150 miles, then on the way home, fill up AGAIN. Calculate the MPG from that.

PS, another consistent factor with Fits is that the fuel gauges are conservative...that is, the Low Fuel indicator comes on at 1/3 tank. You have 3 of 10 gallons left! How many gallons does the car take at 180 miles?

 

Yeah this has been going on for a few months, I take how much gas I put in the car each time and divide by miles past on the odometer since last fill up.

 

I have 208,xxx on mine. I bought it with 186,000 from a 1 owner from Maine. Surprisingly no rust either, at least not yet. I can tell the last owner didn't take care of the car too well. "Autolite" brand spark plugs, crap oil filter, so I'm sure the coolant never been changed or trans fluid. At least the coolant is still blue from honda. I plan to go all oem and no cheap fluids. If the car lasted this far, im sure it can go another 100k with ease.

So yea, i kinda go by what honda recommends. As for your AT fluid, id go by the book.

 

My checklist of things to check before I try replacing parts:
1. Tire pressure - Make sure it's at least 32psi or more. Ive been running mine at 42 psi for 6 years now with no adverse affects just a slight increase in mpg and slightly bumper ride.
2. Over filled engine oil - Extra oil in the pan does not protect the engine anymore than normal, it does cause frothing of the oil which in most cases is bad and causes excess drag on the crankshaft which leads to a slight loss in mpg.
3. Over filled transmission fluid - Too much fluid = increased energy to move fluid = dip in mpg
4. Remove excess weight in the car - self explanatory
5. Dragging brakes - Caliper guide pins can seize up over time but with a good cleaning and relubrication it can help keep the pads from dragging on the rotor and improve mpg slightly.

Too sleepy to think of more but other things you may want to consider are a valve adjustment, alignment check, air filter replacement.

Most of these are free if you know how to do it and may make noticeable differences in mpg especially if you do them all. Hope that helps