Gonna pick up some new plugs, air and oil filters to try and improve mpg on my 2011 Fit Sport, is there anything else I'm unaware of changing? And what plugs should I get? I know nothing about this stuff hahaha, thanks!

 

I doubt that there is going to be a big change unless you're blowing black smoke, engine coughing, etc. As you already know, for a small car, the MPG isn't what many have hoped for. You didn't mention if MT or AT. The way you drive a MT could make more difference than new plugs. BTW, I put the same plug in as it came with new but can't remember what it was 3 yrs ago.

The one thing that could make a difference is if a plug or two is loose. My avg MPG ('11 Sport AT) dropped from 32 to 24-26 and thinking back I started to smell gasoline on startup - 3 yrs ago. Tight plugs will boost MPG.

Good luck

 

Yeah, my Fit is an Auto (AT) that I bought recently expecting to get 35mpg+ and I'm at 24mpg on my recent 3 full tanks. I'm trying to get everything in order to hopefully get the mpg's up.

 

Stick with the NGK or Denso iridiums for the plugs. Honda OEM on the oil filter and your choice on the air filter.

As noted above, these cars are prone to having loose plugs, so that could be your issue. Make sure to blow out the plug wells before removing the plugs in case some sand or dirt has made it's way into the plug wells. Don't want the sand to damage the threads.

I've heard you can do the plugs without removing the cowl, but we removed it on my friends GE to gain a ton of extra access.

 

My big plan is to adjust my valves (~70k miles) this summer. Everything else seems in good running order.

What miles on yours? Us knowing that could help guide our advice for what it's worth.

 

I like to use factory plugs and filters. I also use Honda MT fluid. Don't know about AT.

 

Mine is a rebuilt 2011 AT with 66k on it. I bring up the rebuilt part in order to be totally honest, but I've seen pictures of the damage and have had it looked at by a mechanic and was told it was sound - all airbags intact, idiot lights intact, and odometer is original and correct.

 

Go with K&N.

 

If your filter is old, replacing it could help. Going with a higher flow filter can too, but you will let incrementally more grit into the engine. There is no free lunch on that one; it's just a judgment call. If you don't consistently drive through blowing sand, your risk is probably low.

This is not a BMW so any kind of Honda supplied or other good brand plug will do. I would not buy a cheap set of plugs, odds are you will have to replace sooner and it's a pain to get access.

I have heard while you have the cowl off, you should measure the valve clearances and adjust if needed. I plan to take the cowl off this summer for other reasons and TBH it doesn't look all THAT difficult, just going to take an extra 20 minutes or so on either end.

 

Also had a thought that you may find your mileage is a LOT better in the summer. Since you bought the car in the winter, you may not be experiencing the best it can do. My mileage, mixed city/highway, drops pretty consistently from 32mpg to 28mpg or lower in the winter. This is a big change, due to gas quality, warmup time, and idling.

If it were just me driving the car, I could probably get 34mpg without too much trouble in the summer. 35+ or even touching 40 is not impossible for lower-speed highway driving. Just to give you a sense. But those GE fits we have run with an older engine design and a traditional 5-speed AT and they aren't super aerodynamic. So compared with a modern car - direct injection, CVT, underbody fairings, kammback styling - the MPG has never been quite as good as I had hoped.

Still! 35 is not bad! Guys driving F150s tell me they are envious! Of course they aren't willing to give up their truck either ... +/-

 

I thought you can go til 100 k miles (160 K km) before having to replace the spark plugs, according to Honda. I tend to trust Honda engineers a lot more than random "specialists" on the internet, or mechanics that haven't learned anything new since the 80s.

Also I've noticed the engine air filter stays ridiculously clean in the GE Fit.
Even after 2 years and 30,000 miles my filter is still fine, which is double the recommended interval by Fram. With fuel injected cars you can actually run them just fine with a dirty filter and likely get better fuel mileage than all the fools with high-flow filters. More air = more gas burnt.

And I think your current fuel mileage is from driving & weather conditions rather than the physical state of plugs & filters.

1) has it been cold where you live, below freezing?

2) do you have winter tires?

3) when did you last check the tire pressure? what is it?

4) do you drive short trips, mostly city or stop & go traffic?

5) do you idle the car?

The cheapest thing to do would be to filler 'er up and go for a nice long calm drive in the 55-60 mph range for at least an hour on clear roads. If you're not getting 35 mpg doing that, then your car likely needs serious maintenance.

 

1) It has been cold. In the 30-40s.
2) No, they are regular tires.
3) I've kept the tire pressure around 32.
4) Over three full tanks I've made four 3hr trips (interstate with hills in WV & KY) and the rest has been city.
5) I don't idle much.

So all said and done with those three tanks I've gotten 25mpg, 25mpg and 28mpg. You mentioned serious maintenance, what could be wrong?

 

For me, 35MPG is rare here in PA (shorter trips, hilly, and not as cold as Canada). You can also see that the dash MPG meter vs. hand calculating your MPG swings +/- all of the time per fill-up but for the life of the car (369 fill-ups), those two MPG calculation methods "on average" agree.

I would keep driving the car until you get used to it, get a better sense for its behavior, and you get more info on gas mileage since it does vary, tank by tank, and by the calculation method.

At least at this point, I would check the existing engine air filter to make sure there isn't a rodent nest on it, tap it on a hard surface to clean it and keep using it unless it is completely black & oily (I never saw mine like that but in case).

I wouldn't change to a K&N filter or similar at this point. Although the fuel / air relationships at various speeds / loads are already mapped for your car, and therefore, the amounts of gas used wouldn't vary with or without any filter, those hi-flo filters make more noise that you may interpret as being more "racy". I think that your gas pedal foot will be more aggressive and that will kill your MPG.

By all means, fix the obvious stuff like loose lug nuts, TMPS / CEL / Low tire pressure lights / noises but live with it for awhile before making any changes. If you plan to make any big changes, do them one at a time, then if there is a funny reaction, you know where to look.

 

From the descriptions above, it sounds like the car is fairly new to you and was involved in a previous accident severe enough for it to be totaled.

Under those circumstances, I would perform a full service. This would entail:

valve adjustment - cheap and easy to do and called for by the MM at around 60k miles
spark plug change - they are probably OK, but they aren't expensive and you'll be in that area for valve adjustment (car could have idled or sat around at body shop also)
air filter - if looks dirty
cabin air filter - it's due and maybe nasty from body shop
brake fluid - manual calls for brake fluid every 2 years

For tire pressure, I like 38-40 psi in general for most passenger car tires, but this is a user decision. Do at your own risk.

 

I've read on this forum that a loose plug or out of line valve clearances tend to reduce mileage by a substantial amount.

But your driving style alone can easily cause a 30-50% mileage difference.

I have a well calibrated ScanGauge2 that matches my calculated mileage at every fill-up and had trips from work to home averaging 45 MPG because I'm calm, there's no rush, drive at speed limit & try to hypermile where possible.
But on my morning trips to work when I'm accelerating hard to red line, speeding like maniac to make it in time, passing other cars, I can get a 25 MPG average for that trip.

Driving with the help of the instantaneous mileage really makes a big difference. You will notice that when driving at a constant speed, lets say 60 mph, on a flat road that the instantaneous mileage will read 30 MPG if you press harder on the gas pedal and it can also read 45 MPG if you are easing off on the gas pedal to the point you're slightly applying just enough pressure to keep you going constant at 60 mph.

Since we have small 1.5 L engines, any deviation from ideal conditions takes a huge toll on the gas mileage. Every extra body in the car, carrying a heavy load, or driving faster than 60 mph will reduce your mileage considerably. The Fit may look aerodynamic, but it's really not, so faster driving will burn exponentially more fuel.

I keep my tires around 38-40 PSI on the winter set, and 40-44 with the all-seasons.
In the winter months I even use a lower grill block to warm up the engine faster and reduce drag a bit.



I think adjusting the nut behind the steering wheel is the first step.

 

Sounds to me like something major is wrong if you're only getting 22-25 mpg. Does your CEL work? With the history of being totaled who know what was done to get it back on the road. I'd start with pulling codes and see if anything is in there.

 

What does CEL stand for? And what do you mean by pulling codes?

 

"C" Check "E" Engine "L" Light

 

I'm in the high 20s to low 30s MPG range probably because:
1.) Auto Trans - a little more difficult to "hyper-mileage" and I hate to tailgate and won't do it
2.) Short trips every day (total usually 50-60 miles per day if I go out)
3.) Hilly terrain (300 ft above MSL to 3,000 ft above MSL)
4.) Pennsylvania winter weather vs Texas / Florida winter weather
5.) 205/50-16 tires of 16x7 wheels vs OEM 185/55-16 tires on 16x6 wheels
6.) Tire pressure is 29 psi in all tires (never above recommended on door jam)
7.) I carry a lot of extra weight with tools, equip, spare parts (only one person ever sat on the back seats when car new)
8.) I'm a nervous person trying to get too much done, so I probably drive more aggressively than others (I can get over 100 mph going down this one hill on the highway heading to the office)

 

I am not saying this is your problem but these are some things to think about.

Cold weather will negatively affect gas mileage.

Winter mix fuel will negatively affect your mileage. If my memory is correct that is May 1 through Sept 30 with a few exceptions like all of the Peoples Republic of California.