From http://www.9ss1.dk/porsche944
Driver's Manual
IMPORTANT For your own protection and longer
service life of your car, please heed all
operating instructions and special
warnings. Ignoring them could result in
serious mechanical failure or even
physical injury.
WKD 944021 8 M 6/86 Edition 87
© Dr. Ing. h. c. F. Porsche Aktiengesellschaft
All rights reserved.
Printed in Germany
Your car may have all or some of the
components described in this manual. Should
you find explanations of a feature or equipment
not installed in your car, your Porsche dealer will
be glad to assist you. Also check with your
dealer on other available options or accessories.
Text, illustrations and specifications in this
manual are based on the information available
at the time of printing.
It has always been Porsche's policy to
continuously improve its products. Porsche,
therefore, reserves the right to make changes in
design and specifications, and to make additions
or improvements in its product, without incurring
any obligation to install them on products
previously manufactured.
NOTE TO OWNERS
In Canada, this manual is also
available in French. To obtain a
copy contact your dealer or write to: NOTE AUX PROPRIETAIRES Au Canada on peut se procurer un
exemplaire de ce Manuel en fran-
gais aupres du concessionaire ou
du:
Volkswagen Canada Inc.
Porsche Customer Assistance /
Assistance a la Clientele Porsche1940 Eglinton Ave. East
Scarborough
Ontario M1L 2M2
1
How Emission Control Works
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 continuously senses 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
"cleanup" 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
push or tow starting your vehicle
misfiring of the engine turning off the ignition while the vehicle is moving or
by other unusual operating conditions.
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 law prohibits use of leaded
gasoline in this car.
The Emission Control System and its other
related components are illustrated and
described on the following pages.
101
Emission Control System
1 Fuel pump
2 Fuel filter
3 Pressure damper
3a Pressure regulator
4 Injector
5 Auxiliary air valve
6 Air flow meter
7 Throttle valve switch
8 Temperature sensor
9 Engine temperature sensor
10 Speed sensor
11 Reference mark sensor (TDC)
12 Control unit
13 Ring gear
14 Ignition coil
15 Distributor
16 Relay (fuel pump / control unit)
17 Oxygen sensor
18 Catalytic converter
19 Muffler
102
