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blue flash
i'm hoping someone can help because this is doing my nut.my car is a focus 2005 1.8 diesel.i've just given it a 70,000 service(oil/air filters and europarts engine oil 5w30).was getting anything from 51 to 54 mpg.and now i'm lucky to get 40 mpg.i can acually see the fuel gauge going down slowly when driving.
so if anyone has an idea,that would be great as have a 500 mile trip to do next month.cheers guys.
ZetecSmitch
try re-setting the ECU? unplug the battery for 30 mins then plug it back in. keep your radio code to hand! thats not good mpg though! im getting more than that from my 1.8 petrol!!!
blue flash
yeah have tried that 4 times,but still the same.
FOCA
Its a "learning" ECU, so it takes a bit of time for it to "learn" (different conditions etc)

the colder weather can have an effect on MPG because a diesel has a better MPG once its warmed up, it can take a long time to warm up in cold weather (if it ever really does) especially for short trips

Winter diesel has anti-freeze in it and there is a small? drop in mpg with this too

Same with winter tyres (more drag)

Check your brakes are not binding and your tyres are at the highest recommended pressure

try resetting your avarage MPG, round town driving can drop the avarage down

are you driving harder, more weight in the car, or shorter runs, round town or in heavy traffic -

seems a big drop in MPG though
artscot79
With the cold weather diesels take far longer to warm up and it effects mpg just as it does in a petrol it may be the cold and nothing more also check the underneath of the fuel tank for any leaks
blue flash
thanks for your reply guys,foca,i have been getting 50+ mpg even in really cold weather.tyres are at 35psi, and brakes are not binding.have done a 70 mile trip this morn and the mpg has gone down to 37.9.i'm driving the same roads in the same way,of the 2 i'm driving MORE carefully.and artscot79,i used to leave it running for 15 mins in cold weather to warm up a bit before going for a trip and still got 50+ mpg.no leaks under the car either.is there a fuel sensor somewhere on it that maybe on it's way out.thanks for your replys guys..
artscot79
very strange indeed then have you checked the air filter is housed correctly and alls tight
blue flash
yep just had a look,and it's all fine.
Pitmonster
Has this MPG been validated by manual calculation (brimming the tank and crunching the numbers) or is it just what the trip computer says ?

I use an app to work out my fuel economy, and I check that figure back to what the trip computer says.
In the summer my trip computer was accurate to 1%
Now it's colder, my trip computer is out by 10% (it says 45, actual is 50).

Maybe this has something to do with it?

And diesel fuel economy does suffer in cold weather, as the engine takes so long to warm up

You say you can actually see the fuel gauge going down. Perhaps is was also doing this before, but you didn't notice it?
blue flash
i must admit pitmonster i'm going what the trip says,havent done the full tank way yet, no the gauge has always been steady when driving,it makes me wonder weather the gauge is faulty.it's only gone wonky since it's had a service.i've put europarts own engine oil in the car,now i'm no fitter but have been told to change the oil to a better make??. thanks for the advice pitmonster.
alkyz89
[quote name='ZetecSmitch' timestamp='1354231042' post='219035']
try re-setting the ECU? unplug the battery for 30 mins then plug it back in. keep your radio code to hand! thats not good mpg though! im getting more than that from my 1.8 petrol!!!
[/quote]

are you sure your not driving a diesel?? lol you get more than 40mpg in a 1.8 petrol?? i struggle to get 26mpg haha
StanH
Such a large drop would posssibly indicate a blocked air filter, so since it is a new filter is there any chance of a partial blockage somewhere before or after?
blue flash
good shout StanH,will have a look later.
blue flash
well have had a good look at the car today,and i'm still nowhere nearer than when i started.so tomorrow going for a drive as pitmonster suggested then after that i dont know..................................
Stoney871
In cold weather the car will pump in more fuel to compensate for the denser colder air.
In the summer I can get 500 miles to a tank but in winter it drops by about 40-50 miles.
blue flash
i can see your point,but this loss of mpg has only started since it had a service.
Pitmonster
[quote name='Stoney871' timestamp='1354383930' post='219274']
In cold weather the car will pump in more fuel to compensate for the denser colder air.
In the summer I can get 500 miles to a tank but in winter it drops by about 40-50 miles.
[/quote]
I'm seeing the same results, and it was the same last winter
FOCA
[quote name='Stoney871' timestamp='1354383930' post='219274']
In cold weather the car will pump in more fuel to compensate for the denser colder air.
In the summer I can get 500 miles to a tank but in winter it drops by about 40-50 miles.
[/quote]

You are only assuming the denser colder air is the reason for the drop in MPG, it may be insignificant and the reason for the loss of mpg in the winter is the winter diesel we are supplied (with antifreeze added), or the fact modern diesels take so long to warm up in the winter (and don't return a good MPG untill they are warmed up) the last point is the most likely cause (or it may be because of several reasons working together)
blue flash
so assuming foca that your right (im not saying your wrong)would that account for me losing about 15 mpg.
FOCA
[quote name='blue flash' timestamp='1354532101' post='219487']
so assuming foca that your right (im not saying your wrong)would that account for me losing about 15 mpg.
[/quote]

I don't think so, in my experience these things only make a few MPG difference (say 5mpg?/ 10%) and would not make as much as 15MPG difference, if it is correct mabee there is something wrong and the garage has caused your loss of MPG in some way?
james_60
Hi Folks

Just my pennys worth

Did they adjust the handbrake.

If the shoes are unevenly worn and it isnt balanced it could be partially on, on one side.

Check how hot your drums are after a 10 mile run. be carefull because they could be red hot

Jamie
blue flash
No james all the wheels and brakes are fine.sorry to keep ranting on,but just bin on a 30 mile trip,and i'm sitting in the car.37.7mpg was on the dash and within 45 seconds it had gone down to 34.2mpg.now,i'm starting to think this has to be electrics.any ideas.
Pitmonster
Have you done an actual calculation yet, or is this all based on trip computer numbers?
james_60
If this is based on the trip computer which i think it is then its not a correct value

Only A Brim to Brim result will give an accurate figure.

That is why i use Spritmonitor.de (see my mpg figure)

Its low because i have a lead foot (not saying you have a lead foot)

Jamie
blue flash
no pitmonster it's done on the trip,my dad went into hospital sunday night and havent had the time to go for a tidy drive.hoping to do it some time this week.
Pitmonster
I filled up on Sunday and my trip was 13% out from the actual (calculated) MPG

In the last few weeks it was 10% out, and in summer it was 1% out

Clearly the cold weather makes the trip computer less accurate, and its getting worse as it gets colder

I would suggest that a big part of what you're seeing is inaccurate info.

Yes there will be a reduction in MPG because of the cold, but it won't be anywhere as bad as you're thinking - because your car is telling you porkie pies.

To get an accurate calculation you need to fill to the brim, zero your trip (mileage), drive til the light comes on (450-500 miles), and refill to the brim again. Then do the maths based on miles traveled and litres used (from the fuel pump)
It's the only way to truly know. Shorter distances don't give accurate info and can be very misleading.

If you have a smartphone there's plenty of apps that will do the maths for you

Ps hope your Dad 's ok
blue flash
re the contuing sage of my loss of mpg.my dad's ok pitmonster,(thanks for asking)bit of a heart problem,should be out friday or sat.anyway this morn my mrs's car read -3c on her car focus 1.6 diesel 2012 on mine it read 0c and when the car is warmed up the temp needle pointing to normal (12 o clock position),if it throttle it hard it needle goes back to (10 o clock position) then it goes back to normal.it defo has to be electrics now,anyone with idea of what it could be..
Pitmonster
Your temp gauge shows the temp of the water in your cooling system, not the temp of the engine itself.

The water temp will go up and down due to:
* Thermostat opening and closing
* Cooling fan (on the radiator) starting and stopping
This is normal behaviour and is nothing to worry about

As you rev the engine it's entirely possible that the engine reacts by switching on the cooling fan - in anticipation of the extra heat generated by the engine revs - and so the water temp drops.

This may even be a proactive thing controlled by the ECU : better to start cooling the water before it starts to get too hot, not after
cragger89
After reading this, honestly, take it back to the garage you had it serviced by.

The coolant temperature needle should ALWAYS stay rigid at the 12 o'clock position unless there is a fault. My Audi A3 wasn't heating up due to the thermostat always being open. This meant that sat still, it would reach "90 degrees", but the moment you drove it, it cooled down quickly. This affected MPG in the way you are describing - the engine was never staying at the proper temperature (or even reaching it, in my case) so the ECU was adding more fuel to the mixture, meaning it was running rich.

It could be sheer coincidence if a thermostat has failed (or stated to fail, I don't know if they can start to break slowly or not.) But it wasn't doing this before, either that, or the cold weather has made a long fault suddenly become noticable.
Pitmonster
"The coolant temperature needle should ALWAYS stay rigid at the 12 o'clock position unless there is a fault."

With respect, the water temperature will rise and fall under totally normal circumstances.

Temp goes up, fan goes on, temp comes down, fan turns off, temp goes up, fan goes on, temp comes down, fan turns off...

This can cause the gauge to fluctuate from 1/4 to 1/2, and back to 1/4, and back to 1/2, and so on, but its perfectly normal.

You only have to worry if it goes way above 3/4 or into the red.
minnis
[quote name='blue flash' timestamp='1354795604' post='219925']
this morn my mrs's car read -3c on her car focus 1.6 diesel 2012 on mine it read 0c and when the car is warmed up the temp needle pointing to normal (12 o clock position),if it throttle it hard it needle goes back to (10 o clock position) then it goes back to normal.it defo has to be electrics now,anyone with idea of what it could be..
[/quote]
So you're assuming there is a problem that is causing low MPG?
It could be that your computer is wildly innaccurate, and you actually haven't lost much MPG (only that which is normal in winter). I wouldn't bother doing anything until you measure again with a manual fill up. I normally get low 50's in summer, but recently i've been getting very high 40's. However the trip used to be 0.1-0.2mpg out, but now it's showing 44mpg. Others have reported this problem as well.
Don't assume that your car has a major problem just because an innaccurate dashboard display says you do!
cragger89
Respect accepted and I know that the temperature will change all the time, but the needle in general practice shouldn't move (unless there is a fault) - the only time I've seen the temperature needle drop even on a cold day is when I had a thermostat problem.

The temperature gauges doesn't normally even give a roughly accurate reading - it will just go in the middle once it is within the threshold of being at a normal temperature.

You are correct in saying it is only a real worry if it goes in to the red, but if it isn't running at full temperature, it is still a fault which should be resolved. I may not be correct, it's just something else the OP can look in to if he wants to.
blue flash
right men,have been doing some looking about on the net for the past 2 hours,what do you all think about the water temp sensor is faulty.i've read that this sensor water works the fuel mixture as well...
i also would like to thank you all for your answers and hopefully will sought something out soon,cheers Brian.....



















it's only what i've read
blue flash
ok,done the filling the fuel tank,used it all ? then filled it back up again.now acording to the caculations im useing 3 gallans less to a tankfull then what the gauge is showing me.any one have an idea of what could be faulty.gauge itself,gauge in the tank or any thing else,cheers for any answers.
IINexusII
What engine oil exactly did you use exactly? you just mentioned Eurocarparts. was it the A1 type that ford recommend?
artscot79
the focus needle on the temp gauge will indeed move from the 12 0 clock position as the engine gets up to the point where the thermostat opens and allows coolant through the radiator the pretty cold air will cool it way too much the temp needle drops and the thermostat closes its pretty simple if the gauge never budges ide be concerned having had a few fords not one in the winter has stayed solid in the middle till the engine has had a chance to fully warm up ie more than a 20 mile drive at temps below 6 degrees

it will rise than fall then the thermostat closes and it will rise and likely stay there the thermostat was changed via odb on later focis to show a constant temp even when its not at 90 degrees after lots of people went to ford complaining so from around 80 degrees on the later focis the gaiuge actually shows 90 degrees my gauge shows just below 90 however ford tested it and used laser thermometers and it was 90 degrees the gauge nor the sensor or thermostat was faulty other ti vct owners have had the same issue 3mpg is not that much of a difference to be honest even over a full tank and i dont think its anything to worry about the computer isnt accurate its a general ball park figure as is the temp gauge only the fuel gauge is really accurate
FOCA
[quote name='blue flash' timestamp='1359542764' post='231669']
ok,done the filling the fuel tank,used it all ? then filled it back up again.now acording to the caculations im useing 3 gallans less to a tankfull then what the gauge is showing me.any one have an idea of what could be faulty.gauge itself,gauge in the tank or any thing else,cheers for any answers.
[/quote]

The gauge is not accurate, they are "hit or miss" the tank also has a void in the top to allow for expansion, which can fill with fuel - ive got a big write up somewhere about it but can't find it, if i do i will pass it on
blue flash
i just used the europarts own 5w/30 semi oil,cant remember what,bottles goin in the bin.ok thanks foca.
blue flash
ok thanks to artscot 79.it's nice to know the motors not going blow up or worse.


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