C-Max Owners Club banner
1 - 13 of 13 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter · #1 ·
my cmax is doing 59mpg one minute then 37mpg the next ive tried all sorts of drivin and it always ends up at 37mpg ive changed all filters and using millers oil nothing seems to help!! any1 got any ideas?
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #4 ·
hi im getting my figures from the mpg trip on my cmax its a 1.8 tdci


they are changing at the start of a new tank of fuel and plummet by the end of the tank
 

·
Premium Member
Joined
·
2,364 Posts
Do you reset the trip,mpg & average speed each time you fill up?
I always do this & to start with I have had readings of 90,but as you go further,the readings will come down to a more realistic reading.Mine around town (in a 2.0 TDCI) goes down to average 44.
MM
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #6 ·
Yes i reset the trip each time, it starts off high and drops like a lead stone to about 37 mpg no matter the style of driving i do!I travel about 60 mile each day and 40 mile of that is in 2 journeys on motorway!! doesnt seem to make a difference what I do!
 

·
Premium Member
Joined
·
2,364 Posts
Try adding some Millers fuel additive at each fill up.I started doing that after I`d had the car about a month & did notice an improvement.
I also have a Tunit digital adjustable tuning box ( variesbhp & torque ),this has also made a marked improvement although it was over £400.
Last week I went down to Devon for the second time in 2 weeks & got 56/8 going down (3 up fully loaded )there,an average of 54 for the stay & 70 on the run home keeping it at 70 with the odd blast to 85 to get past some lines of artics.
The week before I got 62 each way at 75mph again with the odd speed up (only 2 in car that time ) and the same average while there.
MM
 

·
Premium Member
Joined
·
3,966 Posts
Do you know that the sensors that calculate the MPG are working correctly
I don#t know which they actually are but that's a starting point
Perhaps try a brim to brim fill and see what you get that way as an idea
 

·
Registered
Joined
·
19 Posts
I have c-max 1.6tdci and get 37.2mpg, very seldom on open roads and very seldom get it up to 70mph. Will never have another ford though, gearbox packed up at 48,000mls and only option was 4,000 recon box from ford. Several owners have had same problem. Ford have gone down the pan.
 

·
Registered
Joined
·
241 Posts
Very happy with my 2.0 Tdci get around 55 on a longish run and have just done my first caravan towing trip 1500kg caravan speed around 55mph most of the time and got 35mpg, I have owned cars that didn't do that mpg by them self.
 

·
Registered
Joined
·
15 Posts
I've only owned one car with a fuel computer (not the C-MAX) and never found it massively accurate. I always fill the tank up and work out my economy from the amount of fuel added and the trip reading. For reference I consistently get around 49 MPG from my C-MAX from a mix of motorway (commute, often congested) and town driving. I am referred to by friends as the "Driving Miss Daisy experience" so I might not be the best example.
 

·
Premium Member
Joined
·
3,966 Posts
the 1.6 TDCI of that age seems to regularly do 45 - 50 MPG just about whatever
 

·
Registered
Joined
·
89 Posts
You can get really obsessed by watching the fuel computers figures.
The only sure way is what's been mentioned. When the fuel light comes on, fill up to the brim. Write down the amount of fuel in litres you filled. Reset your trip meter. When the fuel light comes on again, note the trip meter mileage then divide the amount of fuel by the milage.
Obviously, you'll have to convert litres to gallons, but that's easy.

<h2 ="r" style="font-size: 138%;">1 Imperial gallon = 4.54609188
litres

</h2>
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top