Choosing The Right Fuel With A Flex Fuel Vehicle; Octane Recommendations; Running Out Of Fuel - Ford Super Duty Owner's Manual

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Choosing the Right Fuel With a Flex Fuel Vehicle (If Equipped)
Note: If your vehicle is FFV capable, it will have a yellow colored fuel cap.
Flex fuel vehicles are designed to use only ethanol fuel blends which
contains 51 to 83% ethanol and UNLEADED FUEL Regular unleaded
gasoline or any mixture of the two fuels.
It is best not to alternate repeatedly between gasoline and E85. If you do
switch fuels, it is recommended that you add as much fuel as possible—at
least half a tank. Do not add less than five gallons (18.9 liters) when
refueling. You should drive the vehicle immediately after refueling for at
least 5 miles (8 kilometers) to allow the vehicle to adapt to the change in
ethanol concentration. If you exclusively use E85 fuel, it is recommended
to fill the fuel tank with regular unleaded gasoline at each scheduled oil
change.

Octane Recommendations

high altitude areas. Do not use fuels with a posted octane rating below 87.
Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily under most driving conditions while you are using fuel
with the recommended octane rating, see your authorized dealer to
prevent any engine damage.

RUNNING OUT OF FUEL

Avoid running out of fuel because this situation may have an adverse
effect on powertrain components.
If you have run out of fuel:
• You may need to cycle the ignition from off to on several times after
refueling to allow the fuel system to pump the fuel from the tank to
the engine. On restarting, cranking time will take a few seconds longer
than normal.
• Normally, adding 1 gallon (3.8L) of fuel is enough to restart the
engine. If the vehicle is out of fuel and on a steep grade, more than
1 gallon (3.8L) may be required.
• The service engine soon indicator may come on. For more information on
the service engine soon indicator, refer to the Instrument Cluster
chapter.
See Settings in the Instrument Cluster chapter for information on
calculating DTE (Distance to empty).
2013 F-250/350/450/550 (f23)
Owners Guide gf, 2nd Printing, December 2012
USA (fus)
Fuel and Refueling
Regular unleaded gasoline with a
87
pump (R+M)/2 octane rating of 87 is
recommended. Some stations offer
fuels posted as Regular with an
(R+M)/2 METHOD
octane rating below 87, particularly in