Groups

    is something wrong with my car?

    had my car serviced beginning of last month and since then appears to be using more fuel. just recently over the last few weeks my average mileage has gone down from 33.3 to 32.2. it isnt alot i know but im driving more carefully since realising it was guzzling the fuel. someone told me cars use more fuel after a service and also use more fuel in the colder weather so do i just put it down to this?

    36 Comments

    It's broken I'd sell it before the brakes stop working and it crashes into a wall.
    Edited by: "numptyj" 26th Oct 2010

    Banned

    check your tyre pressure and empty all the rammel out the boot.

    Original Poster

    whatsThePoint

    Do you drive the same route at the same speed, stopping at the same … Do you drive the same route at the same speed, stopping at the same traffic lights ever time to do exactly 33.3 to every gallon



    ive been driving to all the same places since i got it back in february

    Banned

    whatsThePoint

    Do you drive the same route at the same speed, stopping at the same … Do you drive the same route at the same speed, stopping at the same traffic lights ever time to do exactly 33.3 to every gallon



    i was wondering how they worked out this too - lol

    Original Poster

    slamdunkin

    check your tyre pressure and empty all the rammel out the boot.



    wont tyre pressures have been checked at the service? also nothing in the boot but a road atlas

    cold air is more dense so to keep the air fuel ratio more fuel is needed

    take the handbrake off

    Original Poster

    whatsThePoint

    mpg should get better after a service not worst,but to counter that cold … mpg should get better after a service not worst,but to counter that cold weather will increase the fuel used as the cloke will be on more when you first start it


    so you dont think its anything to worry about?

    Original Poster

    its a fiesta ST

    Banned

    1mpg drop jesus this is a troll thread avoid!

    Original Poster

    lumoruk

    1mpg drop jesus this is a troll thread avoid!



    not a troll thread at all, i did say i know its not alot. the point is im driving more carefully and the mpg is dropping when if anything it should have risen. if its possible there may be a problem then by finding out earlier rather than later it could save more damage being done and cheaper to solve. youre the one trolling my thread when you have nothing useful to say

    Banned

    but how can you possibly know the speeds you travel at for every part of every journey, and time spent in traffic or traffic lights, etc,etc

    Original Poster

    whatsThePoint

    This from AutoExpress"Ford quotes an official combined figure of 38.2mpg, … This from AutoExpress"Ford quotes an official combined figure of 38.2mpg, and we returned 25.5mpg"But why buy a performance car if your going to worry about mpg


    im not worried about that as such, more the reason it could be dropping. if it is normal to drop after a service and in the cold weather then fine, if not then i know it may be something else

    Original Poster

    sassie

    but how can you possibly know the speeds you travel at for every part of … but how can you possibly know the speeds you travel at for every part of every journey, and time spent in traffic or traffic lights, etc,etc



    i dont know for every part. the car has a screen in the dash which tells me the average mpg

    Banned

    Stop using this site....your eating to much Ben and Jerry's.....Now go on a diet and watch your consumption

    Banned

    donna-lou

    i dont know for every part. the car has a screen in the dash which tells … i dont know for every part. the car has a screen in the dash which tells me the average mpg



    exactly that only calculates petrol used and miles covered, doesnt calculate speeds, time spent in traffic, etc,etc

    Banned

    Have you ran the engine in the morning prior to driving ,in order to defrost the windscreen

    Original Poster

    slamdunkin

    Have you ran the engine in the morning prior to driving ,in order to … Have you ran the engine in the morning prior to driving ,in order to defrost the windscreen


    only once and the mileage was dropping before that. was only for a couple minutes anyway not like it was running for a long time

    Natural variation, don't let it bother you. Unless you see a 5+ difference I wouldn't spend time thinking about it.

    Original Poster

    whatsThePoint

    at what rpm do you change gear and how late do you leave the braking when … at what rpm do you change gear and how late do you leave the braking when your coming to a stop?


    dont know exactly lol but roughly around 3000 id say. no dont leave braking too late, even more so lately with the fuel going down. im definetly driving more sensibly now than before which is why im wondering if somethings wrong

    Original Poster

    greg_68

    Natural variation, don't let it bother you. Unless you see a 5+ … Natural variation, don't let it bother you. Unless you see a 5+ difference I wouldn't spend time thinking about it.



    thanks. hopefully it wont drop anymore

    whatsThePoint

    at what rpm do you change gear and how late do you leave the braking when … at what rpm do you change gear and how late do you leave the braking when your coming to a stop?



    retardation from using the brakes wont consume fuel, if shes engine braking then that will. But ye OP is a bit OTT me thinks.

    Same fuel?

    slamdunkin

    check your tyre pressure and empty all the rammel out the boot.

    whatsThePoint

    mpg should get better after a service not worst,but to counter that cold … mpg should get better after a service not worst,but to counter that cold weather will increase the fuel used as the cloke will be on more when you first start it



    Ah, but when did you put the road atlas in the boot? That could be the culprit



    The cloke? What's that? Is it like a car cover type thing?

    Original Poster

    Ilnf

    Same fuel?


    well its from the same petrol station, just standard unleaded

    Sounds like it's the Nut behind the wheel...

    Supermarket petrol station or oil company petrol station?

    Original Poster

    Ilnf

    Supermarket petrol station or oil company petrol station?



    oil company. its a jet garage

    check the air filter(should be quite clean if new), spark plugs(and gaps) and most important check you tyre presurres and tyre conditions when cold. Find out what they actuaqlly changed

    The cold weather uses the same as warm weather except : the heated windows/heaqter/AC more lights/wind screen wipers etc(i.e the more elec u consume the more the alternator needs)


    whatsThePoint

    can't be any worst than my xjs used to be, if i selected 1st and put my … can't be any worst than my xjs used to be, if i selected 1st and put my foot down it said 1



    haaaa ! i used to have a 6.0 v12 xjs with a 3gear auto didnt careabout petrol when it was 60p/litre

    you have had a service you say, but not all places do what they claim to have done

    1mpg or so drop is not too much.

    im guessing you are worried about the mpg going even low

    it could be many things, a leak, even a tiny one. smallest or smallest holes in the exhaust can cuase low mpg... get this checked out, its free to do so from most places.

    put your hand near all wheels after driving for a very long time, and see the difference in the heat from around the brake area (if that makes sense) if you feel a lot of heat its a sign of your brake calliper being stuck and this would mean your brakes from that side are always on, hence low mpg

    it might be worth while to do a diagnostics, costs about £20 or £30, it might point out that your o2 sensor is not working, hence taking in too much fuel. it would more or less pin point many faults in the car, even if no dashboard light is on in some cases.

    wheel alignment can also help improve mpg, costs about £20 or £30

    again like others said.. check tyre pressure

    You tend to use more fuel in cooler weather.

    Anything that uses electric will cause more fuel consumption, i,e blowers, wipers, lights etc

    Also choke will stay on for longer, Plus traffic tends to slow down in wetter weather.

    Plus natural wear on suspension, brakes tyres etc

    Plus cooler air in tyres.

    Lots of slight little things can impact fuel economy, Also any extra weight will affect it, All that loose change lol.

    1 mpg less is actually probably very good for this time of year..!!!

    Apologies for the American temperatures - but you get the idea.

    As if we really needed another reason to hate winter.

    Those of us living in northern climes have already started to notice the seasonal decline in fuel economy, even with careful attention to sagging tire pressure (probably the best known effect of the mercury's slide).

    Yet, despite diligent all-around maintenance and continued careful driving, cold weather fuel consumption can be dramatically worse than in warm temperatures.

    How much worse?

    Have a gander at these calculations for a Honda Civic hybrid at 60 MPH in varying ambient temperatures:

    MPH-----AMBIENT-TEMP-----MPG (US)

    60------------95----------52.98
    60------------85----------52.62
    60------------75----------51.16
    60------------65----------49.12
    60------------55----------47.22
    60------------45----------44.67
    60------------35----------43.05
    60------------25----------41.54
    60------------15----------39.41
    60------------05----------38.09

    Look at the extremes: the coldest MPG is 28% lower than the warmest. (Source.)

    My own experience supports this: 12.5% worse mileage during the colder half of the year (Oct 15 to Apr 15) than for the warmest half (Apr 15 - Oct 15), on average 2002-2004 in my 1989 Accord. Comparing just the warmest months (Jun-Aug) to the coldest (Dec-Feb), the difference is even more apparent - 21.2% worse (2002).

    Why so bad? Off the top of my head, I could think of a couple of reasons to explain it, but together they didn't seem significant enough to account for the magnitude of the change. With this mystery to solve, I hit Google. And here's what I learned...

    9 reasons your winter fuel economy bites

    1. More idling

    This should be a no-brainer, yet parked idling cars are a common sight in cold weather. Resist the temptation to idle your car to warm it up. An idling engine gets 0 mpg. Consider also that idling the engine does nothing to warm up the tires and drivetrain.

    Even in the coldest weather, you can begin driving after 30 seconds from a cold start - keep speeds low/moderate and use gentle acceleration until the temperature gauge starts to climb (source).

    2. Low tire pressure

    Of course you're smart enough to keep up your tire pressure as the temperature drops, right? A 10-degree (F) change in ambient temperature equates to a 1 psi change in tire pressure (source). Fuel economy declines 0.4 percent for every 1 psi drop (source).

    3. Increased rolling resistance

    Even if you're completely attentive to proper tire pressure, cold ambient temperatures will still cause your tires to return worse mileage. That's because a tire's shape isn't completely round - the sidewall bulges out at the bottom, and where the tread meets the road the small contact patch is actually flat. As the tire rotates, it constantly deforms to this shape, and this deformation requires more energy when the rubber is cold and hard. Rolling resistance at 0 degrees F is 20% greater than at 80 degrees (source 1, source 2).

    4. Crappy road conditions

    It's increased rolling resistance of another kind: driving through slush and snow. And then there's its wasteful polar (no pun intended) opposite: no friction at all! (A.K.A. wheelspin on ice.)

    5. Lower average engine temperature

    In the winter, an engine takes longer to reach operating temperature and cools off faster when shut off. Since the engine management system orders up a richer mixture when cold (proportionately more fuel in the air/fuel combination), more fuel is being burned overall.

    A block heater can offset this problem (improving fuel economy by 10% in sub-zero conditions - source), as can garage parking, and combining trips (to minimize the number of cold/hot cycles).

    Also related...

    6. Higher average lubricant viscosity

    Engine oil thickens as it cools. So does transmission and differential fluids and even bearing grease. Significantly more energy is needed to overcome the added drag these cold lubricants cause.

    Using synthetic fluids can address this problem, since their viscosity changes less at extreme temperatures than traditional mineral fluids.

    7. Weaker gasoline

    Gasoline doesn't vaporize readily at very cold temperatures. So oil companies formulate fuel differently for cold-weather markets in the winter. Unfortunately, the changes that provide better cold vaporization characteristics also result in less available energy for combustion. You won't get as far on a liter of winter gas as you will on a liter of summer gas. (Source.)

    8. Higher electrical loads

    In colder temps, you use electrical accessories more often:

    - lights (in higher lattitudes it's darker in the winter)
    - rear window defroster (because it's easier than using the ice scraper, right?)
    - heater blower motor (I don't have a/c, so this isn't balanced out during warm conditions); heated seats/mirrors
    - windshield washer pump (because it's easier than using the ice scraper, right? And for frequently cleaning off dirty road spray.)

    9. More aerodynamic drag

    No, I'm not referring to the layer of snow you're too lazy to brush off the top of the car (though that would hurt mpg too).

    A vehicle's aerodynamic drag is proportional to air density, and the density increases as temperature drops. For every 10 degree F drop in temperature, aerodynamic drag increases by 2% (source).


    1mpg reduction.......... have you not felt a drop in temp recently ? theres your answer... more drain on the car.. heaters, lights etc etc..

    If it had dropped by 50%, then yes they may be an issue, but just 1 MPG........ I can knock my average down by 10mpg if i drive it hard.

    colder weather?
    Post a comment
    Avatar
    @
      Text
      Top Discussions
      1. Veteran TV host Sir Bruce Forsyth dies at 892529
      2. Veteran TV presenter doesn't die but gets damages from the Police - is that…66
      3. Just heard this...2 ★★★★★★★★★★★★★★ congrats to all on 392k ★★★★★★★★★★★★★★7764306
      4. ❅☁☁❅ I want☼to talk☼about the☔WEATHER☔no politics☃no religion❅☁☁❅18846211

      See more discussions