Catalytic Converter - Saab 2004 9-5 Owner's Manual

152 Starting and driving
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.
• 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.
NOTICE
• If the engine sounds strange there is a
fault in the system. Have the car
checked without delay by an autho-
rized Saab dealer.
• The use of fuel with too low an octane
rating can cause serious engine dam-
age.
WARNING
If 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.
Important considerations with cata-
lytic converters
NOTICE
Use only unleaded gasoline. Leaded gas-
oline is detrimental to the catalyst and
oxygen sensor and will seriously impair
the function of the catalytic converter.
The 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).
To ensure that the catalytic converter con-
tinues to function properly, and also to avoid
damage to the converter and its associated
components, the following points must be
observed:
• Have the car serviced regularly in accor-
dance with the service program. The fuel
and ignition systems are particularly
important in this context.
• Always be alert to any misfiring of the
engine (not running on all cylinders) and
any loss of power or performance. At the
first sign of a malfunction, reduce speed
and take the car to an authorized Saab
dealer as soon as possible.
• If the engine fails to start (in very cold
weather or if the battery is flat), the car can
be push started (manual gearbox only) or
started using jumper cables to a donor