Porsche 928 S4 – Owner’s Manual |
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Model Year 1987 From
the “Porsche 928 S4 Owner’s Manual”, available from 928 Specialists. |
In the Interest of Clean Air Pollution
of our environment has become a problem that is of increasing concern to all
of us. We urge you to join us in
our efforts for cleaner air in controlling the pollutants emitted from the
automobile. Porsche
has developed an emission control system that controls or reduces those parts
of the emission that can be harmful to our environment. Your Porsche is equipped with such a
system. Porsche
warrants the Emission Control System in your new car under the terms and conditions
set forth in the Warranty & Maintenance booklet. You,
as the owner of the vehicle, have the responsibility to provide regular
maintenance service for the vehicle and to keep a record of all maintenance
work performed. To facilitate
record keeping, have the service performed by authorized Porsche
dealers. They have Porsche
trained mechanics and special tools to provide fast, efficient service. WARNING To
assure efficient operation of the Emission Control System:
Starting
Parking
Undercoating
When
an automobile engine is running, it uses energy generated through the
combustion of a mixture of air and fuel. Depending on whether a car is driven fast or slowly or
whether the engine is cold or hot, some of the fuel (hydrocarbons) may not be
burned completely but be discharged into the engine crankcase or exhaust
system. Additional hydrocarbons
may enter the atmosphere through evaporation of fuel from the fuel tank. These hydrocarbons (HC), when
released into the air, contribute to undesirable pollution. In
addition, carbon monoxide (CO) and oxides of nitrogen (NOx) contribute to
engine emissions. They, too, are
formed during the combustion process and discharged into the exhaust system. To
reduce these pollutants, your Porsche is equipped with a precisely calibrated
fuel injection system to assure a finely balanced air/fuel mixture under all
operating conditions. Oxygen sensor The
oxygen sensor, installed in the exhaust pipe continually sense the oxygen
content of the exhaust and signals the information to an electronic control
unit. The control unit corrects
the air/fuel ratio, so that the engine always receives an accurately metered
air/fuel mixture. Crankcase Ventilation
Through
Crankcase Ventilation undesirable emissions from the engine crankcase are not
permitted to reach the outside atmosphere. These emissions are recirculated from the crankcase to the
air intake system. From here the
emissions mix with the intake air and are later burned in the engine. Catalytic converter
The
catalytic converter is an efficient “clean-up” device built into the exhaust
system of the vehicle. The catalytic
converter burns the undesirable pollutants in the exhaust gas before it is
released into the atmosphere. The
exclusive use of unleaded fuel is critically important for the life of the
catalytic converter. Therefore,
only unleaded gasoline without additives must be used. The
catalytic converter will be damaged by
Do
not continue to operate your vehicle under these conditions, as otherwise
fuel can reach the catalytic converter.
This could result in overheating of the converter. Federal low prohibits use of leaded
gasoline in this car. Fuel Tank Venting
The
expansion chamber and the safety valve prevent fuel from escaping to the
outside at extreme high outside temperatures and when the car is driven or
parked at an incline or in any other nonlevel position. The safety valve works as a
restrictor in the tank vent line between the expansion chamber and the carbon
canister. Vapor Control System and Storage
When
the fuel tank is filled, vapors are collected in the expansion chamber and
filler tube by a vent line leading the vapors to the activated carbon
canister where they are stored as long as the engine does not run. During running of the engine, the
vapors are stored in the activated carbon canister as long as the temperature
controlled ON/OFF valve is in the OFF-position. The
temperature controlled ON/OFF valve stops purging of the canister during all
other running conditions of the engine if the coolant temperature of the
engine is below a defined temperature. Purge System
Fuel
vapors from the carbon canister will be mixed with fresh air taken from the
engine compartment. This mixture
will be directed via two vacuum controlled valves to the air intake system
housing. The
temperature controlled ON/OFF valve has the following functions: To stop purging of the canister during idle (the rich vapor flow from the canister would influence the mixture characteristic). To allow purging of the canister during all other
running conditions of the engine. The vacuum controlled ON/OFF valve has the
function to control the purge flow (high intake vacuum means low purge flow
and low intake vacuum means high purge flow). |
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