2000 SAAB 9-5 octane

132 Starting and drivingUseful tips on cold climate starting If the engine has failed to start after several
attempts in very cold weather, press and
hold the accelerator down to the floor and
run the starter for 5–10 seconds. This will
prevent the engine being flooded (exces-
sively rich fuel-air mixture).
Now start the engine in the normal way – do
not touch the accelerator.
If the engine stalls immediately after starting
(e.g. if the clutch was released too quickly),
do not touch the accelerator when restarting
the engine.
Limp-home modeThe car’s engine-management system
includes a diagnostic function that checks
numerous internal functions after the
engine has been shut off. If a fault is
detected in the throttle system, the
engine-management system puts the throt-
tle system into the limp-home mode. This
limits idling control, disables the cruise-con-
trol system and limits the capacity of the A/C
compressor.
If the limp-home mode is in operation
(“Engine malfunction” light on, see below)
and the outside temperature is close to or
below freezing, you may need to use some
throttle on starting (some pressure on the
accelerator).
If the diagnostic system has detected a fault
in the engine-management system, the
“Engine malfunction” light on the main
instrument panel will come on (see page
49), indicating that you should have the car
checked as soon as possible by an autho-
rized Saab dealer.
Important
considerations for
drivingThe engine-management system in the
Saab 9-5 is called Saab Trionic T7. The
system manages the ignition, fuel injection
and turbo boost pressure.
The Trionic T7 system developed by Saab
is an intelligent engine-management
system designed to achieve optimum driv-
ability under differing driving conditions.
The system makes adjustments automati-
cally, for instance, if the car is being driven
at altitude (oxygen-deficient air), for differ-
ent grades of fuel (AON 87–93) and for dif-
ferent load conditions.
1 Starting and driving
 Refrain from using full throttle before
the engine has warmed up (before
needle in mid-range on temperature
gauge).
 A safety function prevents the engine
from revving faster than 6,000 rpm by
limiting the induction air.
2 Stopping the engine
 Do not rev the engine immediately
before switching it off - stop the engine
when it is idling.
3 Regulating the boost pressure
 The system is optimized for fuel with an
octane rating of AON 90. One of the
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133 Starting and driving
advantages of the system is that it
enables the engine to be run safely on
lower-grade fuel, although not lower
than AON 87.
 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.
Important considerations with cata-
lytic convertersThe catalytic converter is an emission-con-
trol device incorporated in the car’s exhaust
system. It consists of a metal canister with a
honeycomb insert, the cells of which have
walls coated in a catalytic layer (mixture of
precious metals).
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.
WARNING
If the engine is being run with the car on a
rolling road or dynamometer, 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 corre-
sponding road speed.
NOTEUse only unleaded gasoline. Leaded gas-
oline is detrimental to the catalyst and
oxygen sensor and will seriously impair
the function of the catalytic converter.
IB661
2
1
3
Oxygen-sensor-controlled
injection system 1 Engine control module
2 Oxygen sensor (lambda probe)
3 Catalytic converter
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135 Starting and driving
possible running problems) is to keep the
tank well filled.
Before the onset of freezing temperatures in
winter, it may be advisable to add gasoline
anti-freeze to the fuel a few times to dispel
any condensation in the system.
Opening the fuel filler flap in an emergency,
see page 126.
Recommended fuel:The engine in your Saab 9-5 is designed to
operate on unleaded gasoline that has an
octane rating of 87 or higher. 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.
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.
Some Canadian and U.S. gasolines contain
an octane enhancing additive called meth-
lycyclopentadienyl manganese tricarbonyl
WARNING
 Never use fuel for any purpose other
than as engine fuel.
 Fuel is highly flammable and can
cause severe burns. Never use an
open flame in the vicinity of gasoline
and do not smoke when refuelling.
MON + RON
2
IB470
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