Fuel consumption problem

[AFH]

I have an unusual problem. I searched for it and I couldn't find anything like it. I contacted Ford but they didn't give me a proper solution.

 

Everyone of us probably knows that when the fuel tank is full it will give you 630 Kilometers (391 Miles) before it becomes empty. I didn't notice mine was faulty until I retrieved my car after the regular checkup. It went from about 375 to 630 Km and I noticed that I had to refuel less often. But everytime I refuel the maximum limit decreases gradually until it reaches back to 375 and becomes stable. When I took the car to the next check-up I told them about the problem and they said that they will try to solve it. When I returned they said that they didn't find anything and I found out later that they fixed it without knowing. But the problem remains and the limit is still decreasing. I refuel when the gauge reaches 1/4, few times when its 1/8, to the max with the car being turned off, and I also round the price if this little information is relevant. I ended up refueling every 6 days instead of 12+ and always with the same price no matter what the numerical limit reads.

 

I contacted Ford Middle East by email and received a phone call with the representative telling me to unplug the negative side of the battery for 10 minutes. I thought it wouldn't work but it did, but the problem still remains since it decreases with time. It has become a burden to unplug it everytime the limit reaches its minimum, which is probably every month and a half, and the last time I did it the CD player got busted up. I actually didn't send a second email but I hope I can get some help in this forum.

 

Thank you in advance.

Edited June 26, 2015 by AFH

[Waldo]

You need to understand that the "limit" is a calculation of your recent fuel economy multiplied by the amount of fuel in the tank. When you reset the computer, that limit resets to a default but over time it will adjust to your actual driving conditions to be more accurate. Sounds like yours is working exactly as it's supposed to

 

The number of km to empty is just a projection, it has no influence at all on the actual fuel economy or the amount of fuel in your tank.

 

The only way to correctly determine if you have a fuel economy problem is to note the number of liters you put in to fill it up and how many km you drove since you last filled it up.

[WWWPerfA_ZN0W]

Definitely do the manual calculations, like Waldo said, to see if there might be an instrumentation issue or an actual parts issue. Pull codes to see if there's anything related to the fuel or the EVAP system. The codes are not a be-all end-all solution, but can get you off to a good start in diagnostics.

[AFH]

I use premium 91 RON unleaded petrol and mostly fill it with 60 liters. I just checked that the car consumes 16.3 liters / 100 KM and the average speed is 35 KM/h. This is the first time I make calculations and I will start tracking the distances, so I made an estimate by dividing 72 liters by 16.3 and it gave me 442 KM to E. Now I'm starting to doubt myself and feel a bit dumb even though I'm sure the fuel gauge runs down slower when the DTE is high and I spend more days without refueling in a somehow routine driving every week that is mostly on open roads. But if DTE is based on these calculations I don't think I witnessed it increase when conditions are better. More calculations are needed then and perhaps another check in the winter is a must since the car drives better back then and in our extremely hot weather I use the A/C in auto to produce maximum flow. I don't drive the 2011 Expedition alot so I don't know the numbers but I will calculate for it too since in my own beliefs it doesn't have the same issue. My friend has a 2014 Edge Limited, his home is much further than mine to the university, and said that his DTE is above 500. It might not be relevant since each car his a different engine but I want to compare and be sure. Also I don't know where I can get a scanner to pull codes around here.

 

I don't know if this should be in another post but it might be related. A smell of burning gas builds up by time and I smell it even if I only push the pedal a bit harder like halfway through. This issue has been there for a long time, maybe ever since I noticed the DTE, and It goes after each check-up when the clean the engine but they haven't told me anything about it even after requesting. Also I'm afraid that unplugging the battery affected the transmission since recently changing to the 3rd and 4th gear isn't smooth. Additionally, it got diffused twice on me recently when I started the car and put the shifter on D with the pedal having no use and the car revving. A simple restart fixed it.

 

Thank you so much for getting me less worried and giving me information that no representative gave. You have all my respect and I would like to say that this website must be seen by every Edge owner.

Edited June 28, 2015 by AFH

[enigma-2]

Wouldn't want to start a war over this, but I read in the Ford magazine a few years ago (when it was still being published) that using premium gas would lower your mileage. Had to with the engine designed to burn 89 octane and knock slightly. The engine's knock sensor would detect the knock and signal the computer to advance or retard the timing. (As well as some other things I didn't understand). With premium, the knock is reduced and the sensor and computer makes the mixture richer to compensate (without a proper knock signal, it falls back to a preprogrammed mode).

sent from my Galaxy S5

[AFH]

Unfortunately we only have premium 91 and super premium 95.

 

Thank you for the info.

[WWWPerfA_ZN0W]

I imagine that might be true IF the engine were not calibrated to recognize and use the higher octane fuels. 2011+ should do fine with these, 2007-10 not so much.

Wouldn't want to start a war over this, but I read in the Ford magazine a few years ago (when it was still being published) that using premium gas would lower your mileage. Had to with the engine designed to burn 89 octane and knock slightly. The engine's knock sensor would detect the knock and signal the computer to advance or retard the timing. (As well as some other things I didn't understand). With premium, the knock is reduced and the sensor and computer makes the mixture richer to compensate (without a proper knock signal, it falls back to a preprogrammed mode).
sent from my Galaxy S5

[majorahole]

I imagine that might be true IF the engine were not calibrated to recognize and use the higher octane fuels. 2011+ should do fine with these, 2007-10 not so much.

im guessing the newer ones are bosch based, and their ecu judges real time MPG by injection time. but its not a dead set calculation, for example, if you change the size of your injectors, the MPG calculation will be off. DTE is determined by the fuel tank level and the calculated average MPG.

 

also when the ECU see's knock it will reduce timing, never increase because no matter how knock comes on (lean running or pre-ignition/detonation from bad fuel or just too much timing) reducing timing is the fastest way to stop knock. now they also might increase fueling too.

 

 

*edit* i didn't realize how old this thread is!!

Edited December 17, 2015 by majorahole

[enigma-2]

*edit* i didn't realize how old this thread is!!

Still good information nonetheless.

[TheWizard]

There are only two grades of gas in Saudi Arabia... Premium 91 and Super Premium 95. The government mandates that the 91 pumps be colored green and the 95 pumps are colored red. But the ratings are RON (Research Octane Number) which is different from the AKI (Anti-Knock Index) used in North America. AKI is a calculated value averaging the RON and MON (Motor Octane Number) values. You'll usually see it posted on pumps as (R + M) / 2.

 

91 RON is equivalent to 87 AKI and would be called Regular here. 95 RON is equivalent to 90 AKI which is slightly above our 89 octane mid-grade gas. They don't have an equivalent to our 93 Premium which would be 98-99 RON.

Edited December 18, 2015 by TheWizard