Fiesta ST MPG Thread

[FiestaAlex]

Also if you're lugging the engine in higher gears at low rpm it's going to use more fuel than being at higher rpm with light throttle.

Don't think you can generalize like that. Just watch the instant read MPG display to learn what helps and what doesn't.

RPM kills mileage more than anything else. At 4k your injectors fire twice as often as at 2k. Pulse width of course makes a difference, but half throttle at 4k can use more than full throttle at 2k, which is why it tells you to shift up when you're using "light throttle at high rpm"

The program isn't wrong or broken, it's trying to get you the best MPG...

As for me - about 26.5 is the best I've ever seen. Lots of heavy traffic, punch it when i get a chance, 60 mile commute every day.

 

[Intuit]

Agreed. I suspect the misperception (which is common) comes from the fact that we get better mileage at high-RPM highway than low-RPM city. On automatic sh*t torque converter based transmissions that difference can be even more drastic. Of course the difference there is non-steady traffic. A lot of energy is wasted through braking and the engines are a lot less efficient during acceleration (and deceleration).

Modern vehicles are engineered around maintaining certain thresholds on emissions. So how much fuel it burns centers more around how much air it intakes, and how oxygen rich that air is. If you restrict airflow (less throttle or simply very hot) it's going to burn less fuel. The throttle plates typically have a hole in them to allow some air through, even when the throttle plate and if applicable, a computer-controlled bypass known as IAC are closed. Every other down stroke on a piston is guaranteed to intake some air. To avoid loosing energy on the compression cycle and potentially throw off emissions, that air must be mixed and ignited. Re cylinder deactivation tech, cam-phaser/VVT technology is progressing. Engineers are rumored to be working on ways to keep the valves open on a particular pair or single cylinder, thereby wasting less energy on the upstroke by eliminating the compression.

 

[MotorboatMcGoat]

Just picked up a 2014 4 door FiST, 15 mile total commute to work and back on a 75-80mph freeway. Mixed with that and city driving/shenanigans, averaging 29mpg so far.

 

[Intuit]

Just picked up a 2014 4 door FiST, 15 mile total commute to work and back on a 75-80mph freeway. Mixed with that and city driving/shenanigans, averaging 29mpg so far.

The dash is not accurate; particularly after a recent reset. Reset your trip meter to zero at the next refill. Then note how much you put in at the next fill-up. Divide the amount on your trip meter by the number of gallons you just put in. It's not a perfect calculation but will be better than the estimate that the computer delivers.

 

[MotorboatMcGoat]

The dash is not accurate; particularly after a recent reset. Reset your trip meter to zero at the next refill. Then note how much you put in at the next fill-up. Divide the amount on your trip meter by the number of gallons you just put in. It's not a perfect calculation but will be better than the estimate that the computer delivers.

Good to know! Next fill up I'll do it and report back. I wonder how accurate the miles to empty calculator is...

 

[TyphoonFiST]

Good to know! Next fill up I'll do it and report back. I wonder how accurate the miles to empty calculator is...

Its within 5 miles.....but dont rely on that...its just a dummy light to remind you it's time to fill up....the best Indicator is figuring it out by miles traveled and gallons in the tank when you fill up...then you will get a feel for your car....I've seen at high as 39.5 mpgs cruising at 65mph and as low as 28mpgs when it's cold here in Mn and on the winter formulation with short trips. That was with the Stock snail also....I'm running a Gen2 Gtx2860r currently and will be coming up on my 1st summer with it so I'll see when I go on another road trip....which I think will be to The west coast according to my BAE.

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[MrFiSTer]

Im averaging 21.1 mpg since i bought it new 9 days ago. Kinda disappointed fuel mileage was one of the bigger factors for buying this car.

oh btw this is based on the computer readout im sure its actually worse if i calculate....

 

[TyphoonFiST]

Im averaging 21.1 mpg since i bought it 9 days ago. Kinda disappointed fuel mileage was one of the bigger factors for buying this car.

Where do you drive? What type of driving are you doing? Shit canning... clutch smoking...tire shredding it at every given light or stop sign.? What type of gas do you use? The vehicle will get its bearings soon enough....I remember when I got my car I took it slow for a couple thousand miles and then ....eased into it like a prom date....then let the pounding commence.

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[MrFiSTer]

Where do you drive? What type of driving are you doing? Shit canning... clutch smoking...tire shredding it at every given light or stop sign.? What type of gas do you use? The vehicle will get its bearings soon enough....I remember when I got my car I took it slow for a couple thousand miles and then ....eased into it like a prom date....then let the pounding commence.

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15 mile commute each way to work 12 of it freeway. A couple local twisty runs and a trip up to Angeles Crest. Ive settled down and would say im trying to get the best MPG the last few days. At 830 miles now. I use 91 I tried one tank of 87 and its not worth the noticeable power loss to save $3-4 a tank

Not abusing the car by any means but when the manual said no special break in needed just vary speed i did take it literally.

I did have an issue where it was misfiring and threw 2 codes (p0202 and p0302) actually the CEL flashed at me a few times and the car ran like crap for a about an hour so that didnt help matters. The car went back to normal and the codes cleared themselves have an appt with the dealer monday maybe i got a lemon.

 

[DBLE]

Is it a lot of stop-and-go with your commute? If not then something sounds amiss. I bought mine CPO, and I'm basically at the EPA's average on Fuelly at 28.7 mpg with a Fuelly best of 33.6 highway, matching the EPA.

 

[MrFiSTer]

Is it a lot of stop-and-go with your commute? If not then something sounds amiss. I bought mine CPO, and I'm basically at the EPA's average on Fuelly at 28.7 mpg with a Fuelly best of 33.6 highway, matching the EPA.

Normally yes but school must be out its been smooth sailing the last week. 65-80mph most of the way.

Im trying to hypermile it the last couple days eliminating my right foot as the culprit doesnt seem to help all that much so far.

 

[D1JL]

I did have an issue where it was misfiring and threw 2 codes (p0202 and p0302) actually the CEL flashed at me a few times and the car ran like crap for a about an hour so that didnt help matters. The car went back to normal and the codes cleared themselves have an appt with the dealer monday maybe i got a lemon.

Injector #2 open circuit and Cilinder #2 misfire codes and you complain about MPG. LOL
I would have this looked at before any other complaint is made on a new car.

 

[MrFiSTer]

Injector #2 open circuit and Cilinder #2 misfire codes and you complain about MPG. LOL
I would have this looked at before any other complaint is made on a new car.

I got ya but that was about 50-60 miles of the 800. And the mileage was bad before that. Like i said the car is back to normal and the cel disappeared.

 

[Dpro]

The mileage meter will not even begin to read with any kind of semblance of reality for around the 1st thousand miles as it has to learn.

 

[D1JL]

I got ya but that was about 50-60 miles of the 800. And the mileage was bad before that. Like i said the car is back to normal and the cel disappeared.

Pending codes (no MIL) are sometimes recorded long before they are set as HARD codes (MIL on).

 

[Geebs]

3850 miles on my 17' right now....country driving to and from work 18 miles each way. I hammer it once in a while to be sure. I run a 93 octane stage 1 and the car tells me I am averaging 35.7 MPG. For the record, it is still learning because every once in a while it goes up a little bit. I think it is pretty accurate. When I first got it I was averaging 31-32, so break in and beyond will certainly improve the MPG. Gas light came on last week and I said "to hell with it" and went about 20 miles before I refueled, it said I had 27 miles till empty but I wouldn't chance it! That damn needle was pretty close to empty....I was gritting my teeth the whole time but now I know I can get AT LEAST 20-25 miles when it tells me I need to refuel.

 

[Ledfoot]

In 6 months my experience is that, no matter how hard I flog it, 25.7 has been my worst mileage to date. getting 26 mpg is pretty easy to do, even in hard canyon carving.

Driving casually (not slowly...think more like you're maintaining speed and limiting the need for goosing the go pedal) I get between 36 - 38 mpg...all day, any day.

I'd be curious if anyone can shed some light on any mpg dip they get when using AC. I would say it's been 1-2mpg roughly.... more noticeable with hard runs....

I just put my Yakima roof rack on the car and will follow up on how that changes things too.

Currently have +/- 14k miles on the clock...

 

[Raziel510]

I drive to work 1162 miles round trip. I average 29.1 MPG according to the trip computer. I drive mixed speeds from 30 to 80 MPH, mostly on the highway 70 to 80 range.

 

[vivix]

One month of ownership and each tank has been in the 29.5-31 range. Mpg meter is usually 1-2 mpg higher than actual. My commutes mostly highway but we have a lot of hills and the ACs been blasting the whole time. Hoping to see a bit more as she breaks in

 

[XR650R]

I drive to work 1162 miles round trip.

That's a hell of a commute!