octane SAAB 9-3 2002 Owners Manual

149 Starting and driving
2 Stopping the engine
 Do not rev the engine immediately
before switching it off - stop the engine
when it is idling.
3 Regulating the charging pressure
 The system is optimized for fuel with an
octane rating of AON 90. For cars with
205 hp engines and the Viggen, the
system is optimized for AON 93. One of
the advantages of the system is that it
enables the engine to be run safely on
lower-grade fuel, although not lower
than AON 87. However, engine perfor-
mance will fall off slightly, and heavy
loading should be avoided. For best
performance you should use the rec-
ommended grade of fuel, AON 90
(205 hp engine and Viggen AON 93).
 The maximum boost pressure is
adjusted automatically to the knocking
or pinging tendency of the engine.
Occasional, short-lived knocking when
the engine is under a heavy load is per-
fectly normal; the extent will depend on
the grade of fuel in the tank.
 Isolated instances of knocking are
more likely to occur with low-octane
fuel. This controlled form of knocking,
followed by a reduction in the boost
pressure, is a sign that the wastegate is
functioning and is perfectly safe for the
engine.Saab 9-3 Viggen: The Saab 9-3 Viggen has
a high-performance engine which means
that a certain amount of care should be
exercised, in particular when accelerating in
the lower gears. This is especially important
when the road surface is slippery to avoid
the driving wheels from losing their grip.
Limp-homeThe car’s engine management system has
a diagnostics function that, once the engine
has been switched off, checks a number of
internal functions. If a throttle valve fault is
detected, the engine management system
will initiate limp-home mode for the valve.
This means, for example, that idling speed
regulation will be impaired, the cruise con-
trol system will be inoperative, and the
capacity of the A/C compressor will be lim-
ited.
When starting the car in limp-home mode at
temperatures below 32°F (0°C), depress
the accelerator slightly.
If the diagnosis function detects any faults in
the engine management system, the
“Engine malfunction (CHECK ENGINE)
“ indicator in the main instrument panel
will light up (see page 63). The car should
be checked as soon as possible at an
authorized Saab dealer.
NOTEIf constant knocking occurs every time a
load is put on the engine, this indicates a
malfunction in the system.
Have the car checked without delay by an
authorized Saab dealer. NOTEIf the engine is being run with the car on a
rolling road or dynamometer, longer than
for a standard state emission inspection,
to ensure adequate cooling, air must be
blown into the engine compartment and
under the car at a rate equivalent to the
ram-air effect that would be obtained at
the corresponding road speed.
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152 Starting and driving
Recommended fuel:For optimum performance we recommend:
 AON 90 for 2.0 Turbo 185 hp engines.
 AON 93 for 2.0 Turbo 205 hp engines and
2.3 Viggen.
Octane rating is determined according to
the formula:
where MON is the Motor Octane Number,
and RON is the Research Octane Number.
The average of these two values is the
octane rating of the gasoline as it appears
on the pump at a retail gas station. This
value is sometimes referred to as the
"Anti-Knock Index" (AKI) or the "Average
Octane Number" (AON).To avoid deposit formation on the fuel injec-
tors which can cause poor driveability, use
only quality gasolines that contain deter-
gents and corrosion inhibitors. Because
gasolines sold at retail gas stations vary in
their composition and quality, you should
switch to a different brand if you begin expe-
riencing driveability and/or hard starting
problems shortly after refueling your car. In
recent years, a variety of fuel additives and
alcohols or oxygenates have been blended
with gasoline. These types of gasolines may
be found in all parts of the United States and
Canada, but particularly in geographic
areas and cities that have high carbon mon-
oxide levels. Saab approves the use of such
"reformulated" gasolines in its products,
which help in reducing pollution from all
motor vehicles, provided that the following
blending percentages are met by such
fuels:
 Up to 10% ethanol by volume, with corro-
sion inhibitors.
 Up to 15% MTBE by volume (methyl ter-
tiary butyl ether).
 Up to 5% methanol by volume, with an
equal amount of a suitable co-solvent and
added corrosion inhibitors.
NOTE Fill to maximum filling capacity
 Stop filling after the first time that the
nozzle trips to shut off the flow of fuel
 Filling capacity can differ between
different fuel stations and outside
temperature. Fuel tank volume when
nozzle trips to shut off, may vary by
0.5 gal. (2 liters).
 Do not fill fuel all the way up the filler
pipe. The gasoline must be allowed
room for expansion especially during
hot weather.
MON + RON
2
IB1891
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153 Starting and driving
Other, less common, fuel additives used by
some gasoline dealers are also acceptable,
provided that the resultant gasoline is not
more than 2.7% oxygen by weight. In many
cases, you may not be able to determine the
exact type or percentage by volume of fuel
additive in the gasoline you purchase for
your car.
Some Canadian and U.S. gasolines contain
an octane enhancing additive called meth-
lycyclopentadienyl manganese tricarbonyl
(MMT). If such fuel is used, your emission
control system performance may deterio-
rate and the malfunction indicator lamp on
your instrument panel may turn on. If this
occurs, return to your authorized Saab
dealer for service.
However, these blended gasolines are reg-
ulated and should never exceed these rec-
ommended blend percentages and service
station operators should know if their gaso-
lines contain detergents and oxygenates,
and have been reformulated to reduce vehi-
cle emissions. Nevertheless, if you begin to
notice a problem with the way your car starts
or runs shortly after it has been refueled, try
a different brand of gasoline.
NOTEHigher concentrations of methanol than
listed above, or the use of methanol-
blended gasoline without suitable
co-solvents and corrosion inhibitors,
can damage your car’s fuel system,
leading to the need for repairs which are
not covered by Saab’s product warranty.
NOTEThe engine control module (ECM) mon-
itoring the engine parameters also
stores fault codes.
Under certain circumstances, this may
cause constant illumination of the
Engine malfunction (CHECK ENGINE)
lamp , thus indicating a fault that
must be checked by your Saab dealer,
see page 63.
NOTE: always observe the following two
measures:
 Make sure that the fuel filler cap is
screwed on correctly before the
engine is started. Screw on the fuel
filler cap until you hear three distinct
clicks.
 Avoid driving with the fuel low level
indicator illuminated. The symbol
illuminates when less than approxi-
mately 2.5 gallons (10 litres) of fuel
remains in the tank.
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154 Starting and drivingFuel (Gasoline Engine)Use regular unleaded gasoline rated at 87
octane or higher. It is recommended that the
gasoline meet specifications which were
developed by the American Automobile
Manufacturers Association (AAMA) and
endorsed by the Canadian Motor Vehicle
Manufacturers Association for better vehi-
cle performance and engine protection.
Gasolines meeting the AAMA specification
could provide improved driveability and
emission control system performance com-
pared to other gasolines.Canada Only
Be sure the posted octane is at least 87. If
the octane is less than 87, you may get a
heavy knocking noise when you drive. If it’s
bad enough, it can damage your engine. If
you’re using fuel rated at 87 octane or
higher and you hear heavy knocking, your
engine needs service. But don’t worry if you
hear a little pinging noise when you’re accel-
erating or driving up a hill. That’s normal,
and you don’t have to buy a higher octane
fuel to get rid of pinging. It’s the heavy, con-
stant knock that means you have a problem.
If your vehicle is certified to meet California
Emission Standards (indicated on the
underhood emission control label), it is
designed to operate on fuels that meet Cal-
ifornia specifications. If such fuels are not
available in states adopting California emis-
sions standards, your vehicle will operate
satisfactorily on fuels meeting federal spec-
ifications, but emission control system per-
formance may be affected. The malfunction
indicator lamp on your instrument panel
may turn on and/or your vehicle may fail a
smog-check test. See "Malfunction Indica-
tor Lamp" in the Index. If this occurs, return
to your authorized Saab dealer for diagno-
sis to determine the cause of failure. In the
event it is determined that the cause of the
condition is the type of fuels used, repairs
may not be covered by your warranty. Some gasolines that are not reformulated
for low emissions may contain an
octane-enhancing additive called methylcy-
clopentadienyl manganese tricarbonyl
(MMT); ask your service station operator
whether or not the fuel contains MMT. Saab
does not recommend the use of such gaso-
lines. If fuels containing MMT are used,
spark plug life may be reduced and your
emission control system performance may
be affected. The Engine malfunction
(CHECK ENGINE) light on your instrument
panel may turn on. If this occurs, return to
your authorized Saab dealer for service.
In Canada, look for the
"Auto Makers’ Choice" label
on the fuel pump.
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