1999 Mercury Grand Marquis fuel cap

Check engine
Your vehicle is equipped with a
computer that monitors the engine's
emission control system. This
system is commonly known as the
On Board Diagnostics System (OBD
II). This OBD II system protects the environment by ensuring that your
vehicle continues to meet government emission standards. The OBD II
system also assists the service technician in properly servicing your
vehicle.
TheCheck Engineindicator light illuminates when the ignition is first
turned to the ON position to check the bulb. If it comes on after the
engine is started, one of the engine's emission control systems may be
malfunctioning. The light may illuminate without a driveability concern
being noted. The vehicle will usually be drivable and will not require
towing.
What you should do if the check engine light illuminates
Light turns on solid:
This means that the OBD II system has detected a malfunction.
Temporary malfunctions may cause yourCheck Enginelight to
illuminate. Examples are:
1. The vehicle has run out of fuel. (The engine may misfire or run
poorly.)
2. Poor fuel quality or water in the fuel.
3. The fuel cap may not have been properly installed and securely
tightened.
These temporary malfunctions can be corrected by filling the fuel tank
with good quality fuel and/or properly installing and securely tightening
the gas cap. After three driving cycles without these or any other
temporary malfunctions present, theCheck Enginelight should turn off.
(A driving cycle consists of a cold engine startup followed by mixed
city/highway driving.) No additional vehicle service is required.
If theCheck Enginelight remains on, have your vehicle serviced at the
first available opportunity.
CHECK
ENGINE
Instrumentation
7

GAUGES
Standard instrument cluster gauges
Optional instrument cluster gauges
Fuel gauge
Displays approximately how much fuel is in the fuel tank (when the key
is in the ON position). The fuel gauge may vary slightly when the vehicle
is in motion. The ignition should be in the OFF position while the vehicle
is being refueled. When the gauge first indicates empty, there is a small
amount of reserve fuel in the tank. When refueling the vehicle from
empty indication, the amount of fuel that can be added will be less than
the advertised capacity due to the reserve fuel.
E
LOW
FUEL TRAC
CNTLCHECK
ENGINEAIR
SUSPOD
OFF
BRAKEAIR
BAG
TEMP OIL VOLTS FUEL
MPH km/h10 203040506070
80
90
10 0
11 0
12 020 406080100
120
140
160
180
200
H H
L C F H
L
< FUEL FILL DOOR
0000000
0
0 0 0
+ –
F
E
/2 1
N
O
R
M
H
C
LT R
GAL
TO
EMPTY
km/h
MPH
km SCHECK
ENGINE
AIR
BAGSPEED CONTROL
P R N D 2 1
CHECK
TRUNK AJAR LTR/100 kmAIR SUSPENSION
OVERDRIVE OFFDOOR
AJAR
LOW
WASHER
FLUID
DIST TO
EMPTY
TRIP
AAVG
ECON
TRIP
BINST
ECON
AVG
SPEED
km
MILES
/GAL
Instrumentation
12

When lifting a plastic-cased battery, excessive pressure on the
end walls could cause acid to flow through the vent caps,
resulting in personal injury and/or damage to the vehicle or battery.
Lift the battery with a battery carrier or with your hands on opposite
corners.
Keep batteries out of reach of children. Batteries contain sulfuric
acid. Avoid contact with skin, eyes or clothing. Shield your eyes
when working near the battery to protect against possible splashing of
acid solution. In case of acid contact with skin or eyes, flush
immediately with water for a minimum of 15 minutes and get prompt
medical attention. If acid is swallowed, call a physician immediately.
Because your vehicle's engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. To begin this process:
1. Set your parking brake.
2. Put the gearshift in P (Park), turn off all accessories and start the
engine.
3. Let the engine idle for at least one minute.
4. The relearning process will automatically complete as you drive the
vehicle.
²The vehicle may need to be driven 16 km (10 miles) or more to
relearn the idle and fuel trim strategy.
²If you do not allow the engine to relearn its idle trim, the idle quality
of your vehicle may be adversely affected until the idle trim is
eventually relearned.
If the battery has been disconnected or a new battery has been installed,
the clock and the preset radio stations must be reset once the battery is
reconnected.
Maintenance and care
151

SNOW TIRES AND CHAINS
Snow tires must be the same size and grade as the tires you
currently have on your vehicle.
The tires on your vehicle have all weather treads to provide traction in
rain and snow. However, in some climates, you may need to use snow
tires and chains. If you need to use chains, it is recommended that steel
wheels (of the same size and specifications) be used as chains may chip
aluminum wheels.
Follow these guidelines when using snow tires and chains:
²Use only SAE Class S chains.
²Install chains securely, verifying that the chains do not touch any
wiring, brake lines or fuel lines.
²Drive cautiously. If you hear the chains rub or bang against your
vehicle, stop and re-tighten the chains. If this does not work, remove
the chains to prevent damage to your vehicle.
²If possible, avoid fully loading your vehicle.
²Remove the tire chains when they are no longer needed. Do not use
tire chains on dry roads.
²The suspension insulation and bumpers will help prevent vehicle
damage. Do not remove these components from your vehicle when
using snow tires and chains.
WHAT YOU SHOULD KNOW ABOUT AUTOMOTIVE FUELS
Important safety precautions
Do not overfill the fuel tank. The pressure in an overfilled tank
may cause leakage and lead to fuel spray and fire.
If you do not use the proper fuel cap, the pressure in the fuel
tank can damage the fuel system or cause it to work improperly
in a collision.
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157

The fuel system may be under pressure. If the fuel cap is venting
vapor or if you hear a hissing sound, wait until it stops before
completely removing the cap.
Automotive fuels can cause serious injury or death if misused or
mishandled.
Observe the following guidelines when handling automotive fuel:
²Extinguish all smoking materials
and any open flames before
fueling your vehicle.
²Always turn off the vehicle before
fueling.
²Automotive fuels can be harmful
or fatal if swallowed. Fuel such as
gasoline is highly toxic and if
swallowed can cause death or
permanent injury. If fuel is
swallowed, call a physician immediately, even if no symptoms are
immediately apparent. The toxic effects of fuel may not be visible for
hours.
²Avoid inhaling fuel vapors. Inhaling too much fuel vapor of any kind
can lead to eye and respiratory tract irritation. In severe cases,
excessive or prolonged breathing of fuel vapor can cause serious
illness and permanent injury.
²Avoid getting fuel liquid in your eyes. If fuel is splashed in the eyes,
remove contact lenses (if worn), flush with water for 15 minutes and
seek medical attention. Failure to seek proper medical attention could
lead to permanent injury.
²Fuels can also be harmful if absorbed through the skin. If fuel is
splashed on the skin and/or clothing, promptly remove contaminated
clothing and wash skin thoroughly with soap and water. Repeated or
prolonged skin contact with fuel liquid or vapor causes skin irritation.
²Be particularly careful if you are taking ªAntabuseº or other forms of
disulfiram for the treatment of alcoholism. Breathing gasoline vapors,
or skin contact could cause an adverse reaction. In sensitive
individuals, serious personal injury or sickness may result. If fuel is
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158

splashed on the skin, promptly wash skin thoroughly with soap and
water. Consult a physician immediately if you experience an adverse
reaction.
Fuel Filler Cap
Your fuel tank filler cap has an indexed design with a one-eighth turn
on/off feature.
When fueling your vehicle:
1. Turn the engine off.
2. Carefully turn the filler cap counterclockwise 1/8 of a turn until it
stops.
3. Pull to remove the cap from the fuel filler pipe.
4. To install the cap, align the tabs on the cap with the notches on the
filler pipe.
5. Turn the filler cap clockwise 1/8 of a turn until it stops.
If the ªService Engine Soon/Check Engineº indicator comes on and stays
on when you start the engine, the fuel filler cap may not be properly
installed. Turn off the engine, remove the fuel filler cap and reinstall it
being careful to align the cap properly.
If you must replace the fuel filler cap, replace it with a genuine
Ford or Motorcraft part. The customer warranty may be void for
any damage to the fuel tank or fuel system if a genuine Ford or
Motorcraft fuel filler cap is not used.
The fuel system may be under pressure. If the fuel filler cap is
venting vapor or if you hear a hissing sound, wait until it stops
before completely removing the fuel filler cap. Otherwise, fuel may
spray out and injure you or others.
If you do not use the proper fuel filler cap, the pressure in the
fuel tank can damage the fuel system or cause it to work
improperly in a collision.
Choosing the right fuel
Use only UNLEADED FUEL. The use of leaded fuel is prohibited by law
and could damage your vehicle.
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159

Cleaner air
Ford approves the use of gasolines to improve air quality, including
reformulated gasolines that contain oxygenates up to 10% ethanol or
15% MTBE.
Running out of fuel
Avoid running out fuel because this situation may have an adverse affect
on powertrain components.
If you have run out of fuel:
²You may need to crank the engine several times before the system
starts to pump fuel from the tank to the engine.
²Your ªCheck Engineº light may come on. For more information on the
ªCheck Engineº light, refer to theInstrumentationchapter.
Fuel Filter
Your vehicle is equipped with a fuel filter that is mounted on the
underbody.
For fuel filter replacement, see your dealer or a qualified service
technician. Refer to the Scheduled Maintenance Guide for the
appropriate intervals for changing the fuel filter.
If you replace the fuel filter, replace it with an authorized
Motorcraft part. The customer warranty may be void for any
damage to the fuel system if an authorized Motorcraft fuel filter
is not used.
ESSENTIALS OF GOOD FUEL ECONOMY
Measuring techniques
Your best source of information about actual fuel economy is you, the
driver. You must gather information as accurately and consistently as
possible. Fuel expense, frequency of fillups or fuel gauge readings are
NOT accurate as a measure of fuel economy. We do not recommend
taking fuel economy measurements during the first 1 600 km (1 000
miles) of driving (engine break-in period). You will get a more accurate
measurement after 3 000 km±5 000 km (2 000 miles-3 000 miles).
The advertised fuel capacity of the fuel tank on your vehicle is equal to
the rated refill capacity of the fuel tank as listed in the Refill Capacities
chart in this ªOwner Guide.º The advertised capacity is the amount of
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161

the Indicated Capacity and the Empty Reserve combined. Indicated
Capacity is the difference in the amount of fuel in a full tank and a tank
when the fuel gauge indicates empty. Empty Reserve is the small amount
of usable fuel remaining in the fuel tank after the fuel gauge indicates
empty.
The amount of Empty Reserve varies and should not be relied
upon to increase driving range. When refueling your vehicle after
the fuel gauge indicates empty, you might not be able to refuel
the full amount of the advertised capacity of the fuel tank due to
the empty reserve still present in the tank.
Filling the tank
For consistent results:
²Use the same filling rate setting (low Ð medium Ð high) each time
the tank is filled.
²Allow three automatic click-offs when filling.
²Always use the recommended octane rating of a known quality
gasoline, preferably a national brand.
²Use the same side of the same pump and have the vehicle facing the
same direction each time you fill up.
²Have the vehicle loading and distribution the same every time.
Your results will be most accurate if your filling method is consistent.
Calculating fuel economy
1. Fill the fuel tank completely and record the initial odometer reading.
2. Each time you fill the tank, record the amount of fuel added (in liters
or gallons).
3. After at least three to five tank fill-ups, fill the fuel tank and record
the current kilometer (mileage) reading.
4. Follow one of the simple calculations in order to determine fuel
economy:
Multiply liters used by 100, then divide by total kilometers
traveled.
Divide total miles traveled by total gallons used.
Keep a record for at least one month and record the type of driving (city
or highway). This will provide an accurate estimate of the vehicle's fuel
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162