Timitfc Posted December 3, 2015 Share Posted December 3, 2015 Hi All, Over the last 2 weeks i have noticed a sudden drop in MPG in my 2012 Cmax 1.6 TDCI Titanium. I used to receive on average between 44-48 MPG around town / driving to and from work (10 miles trip). However I have recently noticed that on the same journey, and same usage getting around 40-41 mpg - engine sounds fine and doesn't appear any loss in power. Does anyone have any suggestions on what to check as something isnt quite right! Thanks Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 3, 2015 Share Posted December 3, 2015 Diesel engines take longer to reach optimum operating temperature in colder weather & are as a result less economical. How are you measuring the vehicle's average m.p.g. ? Quote Link to comment Share on other sites More sharing options...
Timitfc Posted December 3, 2015 Author Share Posted December 3, 2015 I use the trip computer for ease, however I know this isnt true MPG and i actually get 2-3 mpg less than this. I have noticed the fuel guage go down further based on miles done so I assume its not a sensor issue? Would it be worth getting a diagnostic done? Would it bring up anything that the car wouldnt tell me? Thanks for your help! Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 3, 2015 Share Posted December 3, 2015 When was the fuel filter last changed ? Quote Link to comment Share on other sites More sharing options...
Timitfc Posted December 3, 2015 Author Share Posted December 3, 2015 It had a service about 4k miles ago so I would assume then.. however I will need to check to what exactly was done - could a blocked / clogged fuel filter provide a sudden drop in mpg? Quote Link to comment Share on other sites More sharing options...
jeebowhite Posted December 3, 2015 Share Posted December 3, 2015 The colder weather naturally reduces MPG anyway. The colder air is more dense, which needs more fuel adding to the ratio to give the right bang. 2 Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 3, 2015 Share Posted December 3, 2015 Yes, a poorly functioning fuel filter will cause a loss of m.p.g. 3 Quote Link to comment Share on other sites More sharing options...
iantt Posted December 3, 2015 Share Posted December 3, 2015 It had a service about 4k miles ago so I would assume then.. however I will need to check to what exactly was done - could a blocked / clogged fuel filter provide a sudden drop in mpg?Never assume anything. 2 Quote Link to comment Share on other sites More sharing options...
iantt Posted December 3, 2015 Share Posted December 3, 2015 When was the fuel filter last changed ?Havent we been here already today? Lol 2 Quote Link to comment Share on other sites More sharing options...
Timitfc Posted December 3, 2015 Author Share Posted December 3, 2015 The colder weather naturally reduces MPG anyway. The colder air is more dense, which needs more fuel adding to the ratio to give the right bang. Yes i understand this, however it hasn't really got cold yet and during the 2 winters I have owned the car for it hasn't noticably affected performance! Never assume anything. Sounds like a voice of experience...! I will check the log and come back to you later. Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 3, 2015 Share Posted December 3, 2015 Today & yesterday & so on & so forth . . A million times Ian . . . we can almost predict the answers to the questions we are asking . . . :) 2 Quote Link to comment Share on other sites More sharing options...
jeebowhite Posted December 3, 2015 Share Posted December 3, 2015 I must admit, fuel filter is the best shout at the moment. I had mine changed a few days ago, it makes one heck of a difference. I would also suggest for best performance, replace the air filter too. 1 Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 3, 2015 Share Posted December 3, 2015 The M.A.F. sensor is another potential culprit & is always worth a look & clean up if required 3 Quote Link to comment Share on other sites More sharing options...
Brat673 Posted July 25, 2016 Share Posted July 25, 2016 MAF sensor. What is it and where is it located please? Quote Link to comment Share on other sites More sharing options...
jeebowhite Posted November 23, 2016 Share Posted November 23, 2016 MAF Sensor - Mass Air Flow sensor, its in the housing to the air filter, where you see an electrical connector. Quote Link to comment Share on other sites More sharing options...
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