SAAB 9000. Manual — part 28

4B•2 Emissions control systems

The sensor output voltage alters in a large step
at this point, the ECU using the signal change
as a reference point, and correcting the inlet
air/fuel mixture accordingly by altering the fuel
injector pulse width (injector opening time).

Exhaust gas recirculation system

This system circulates a proportion of the

exhaust gas back into the combustion
chambers during certain operating conditions,
in order to reduce harmful exhaust gas
emissions. This is achieved by effectively
reducing the peak temperatures reached in
the combustion chambers by the introduction
of the inert exhaust gas. Two systems were

fitted - a mechanical system, and an electronic
system controlled by the LH-Jetronic ECU.

If a fault occurs in the EGR system, the

"CHECK ENGINE" warning light on the
instrument panel will be lit, and the
corresponding fault code will be stored in the
LH-Jetronic ECU.

Evaporative emissions control

system

To minimise the escape into the atmosphere

of unburned hydrocarbons, an evaporative
emissions control system is fitted to certain
models. The system is referred to as the
"evaporative-loss control device" (ELCD). The
fuel tank filler cap is sealed, and a charcoal
canister is mounted on the front right-hand
side of the car beneath the right-hand wing, to
collect the petrol vapours generated in the
tank when the car is parked. The vapours are
stored until they can be cleared from the
canister (under the control of the fuel system
ECU via the purge valve, into the inlet tract, to
be burned by the engine during normal
combustion.

To ensure that the engine runs correctly

when it is cold and/or idling, and to protect the
catalytic converter from the effects of an over-
rich mixture, the purge control valve is not
opened by the ECU until the engine has
warmed up, and the engine is under load; the
valve solenoid is then modulated on and off, to
allow the stored vapour to pass into the inlet
tract.

Deceleration device

A deceleration dashpot (or "throttle

damper") is fitted to the throttle lever on the
throttle housing on some models. Its purpose
is to control the deceleration of the engine
during overrun, in order to prevent the
emission of unburned hydrocarbons. If the
accelerator pedal is released with the engine
running at a speed of 3000 rpm, the engine
should take approximately 4 seconds to
decelerate to a speed of 875 rpm.

Automatic idling control (AIC)

Some models are fitted with an automatic

idling control system, which provides
smoother idling, improved cold and warm-up
running, idle speed compensation (to allow for

the operation of the air conditioning

compressor, alternator or power steering
pump), and engine deceleration control.

The AIC valve controls the flow of air

bypassing the throttle valve. The valve is
operated by the ECU.

Pulse-air system

Some models have a pulse-air system,

which supplies air to the downstream side of
the exhaust valves, in order to complete
oxidation of any unburned hydrocarbons

present in the exhaust gases. The system uses

the pressure pulses in the exhaust manifold to
draw the air from the air cleaner.

Secondary air injection

On this system, air is injected into the

exhaust manifold before the lambda sensor
and catalytic converter have reached working
temperature, in order to assist in the
combustion of hydrocarbons. The system is
activated when the engine is started, and its
running time depends on the engine
temperature and the point when the lambda
sensor begins to operate.

Crankcase emissions control

1 The components of this system require no
attention, other than to check at regular
intervals that the hose(s) are clear and
undamaged.

EGR system

Testing

2 If a fault occurs in the EGR system, a fault
code is stored in the LH-Jetronic ECU, and a
warning light is lit on the instrument panel.
Check all wiring and hose connections on the
EGR valve for security. If this does not rectify
the fault, the advice of a Saab dealer should
be sought.

Removal and refitting

Air temperature sensor
3 To remove the inlet air temperature sensor,
disconnect the wiring and unscrew the sensor
from the inlet manifold. Refitting is a reversal
of removal.
Vacuum tank
4 The vacuum tank is located on the left-hand
front of the engine compartment. First, remove
the airflow meter as described in Chapter 4A.
5 Disconnect the vacuum hoses, and remove
the vacuum tank together with the mounting
bracket.
6 Remove the mounting bracket, and fit it to
the new vacuum tank.
7 Refitting is a reversal of removal.
Timing valve
8 The timing valve is located in the line
between the vacuum tank and the EGR valve.

9 Disconnect the wiring and the hoses, noting
their location, and remove the valve.
10 Refitting is a reversal of removal.

Lambda sensor
Testing

11 The lambda sensor may be tested with a
multi-meter by disconnecting the wiring at the

connector, either near the right-hand end of
the inlet manifold (models with LH-Jetronic
system) or on the right-hand side of the

bulkhead (models with Trionic system).
12 Connect an ohmmeter between terminals
1 and 2 on the sensor wiring plug. Do not

connect the ohmmeter to the ECU wiring. The
resistance should be between 2.9 and 4.0
ohms for a 12-watt lambda sensor (unleaded
petrol), or approximately 2.1 ohms for an 18-
watt lambda sensor (leaded petrol and turbo
class 1). The resistance varies with
temperature, and can be as high as 10 ohms.
13 Reconnect the wiring after making the test.

Removal
Note: The lambda sensor is DELICATE. It will

not work if it is dropped or knocked, if its

power supply is disrupted, or if any cleaning

materials are used on it. The sensor should be
renewed every 60 000 miles/90 000 km.
Early models

14 Disconnect the wiring plug at the right-
hand side of the inlet manifold.
15 Unclip the wiring from the cylinder head,

and feed it through to the front of the engine.
Later models
16 Remove the weatherstrip and cover from
the false bulkhead at the rear of the engine
compartment. Lift the right-hand part of the
cover, and disconnect the lambda sensor
wiring plug.
17 Unscrew the screws from the bulkhead
plate, then pull the lambda sensor wiring to the

front of the engine compartment, lifting the air
conditioning pipe where necessary.

18 Where necessary, release the wiring from

the clamp on the coolant pipe, and unscrew
the wiring support bolts as necessary (see
illustration).

19 Where necessary, release the clip near the
lower air conditioning compressor mounting
bolt.

All models
20 Unscrew the sensor from the exhaust
system downpipe, and remove it. The sensor
may be tight, in which case it will help if it is
turned back and forth on its threads as it is
being removed. Note that it is possible to
obtain a special slotted socket, which locates
on the sensor without causing any damage to
the wiring.

Refitting

21 Refitting is a reverse of the removal
procedure. Prior to installing the sensor, apply
a smear of high-temperature grease to the
sensor threads. Tighten the sensor to the
specified torque (see illustration). The wiring
must be correctly routed, and in no danger of
contacting the exhaust system.

Emissions control systems 4B•3

2.18 Removing the lambda wiring support from the front of the

cylinder block

2.21 Tightening the lambda sensor (hidden beneath the deep

socket) with a torque wrench

Throttle damper

Testing

22 Run the engine to normal temperature,

and check the CO content setting and idling
speed (where applicable).
23 Disconnect and plug the distributor

vacuum hose and the EGR hoses, where

fitted.
24 Start the engine, and increase its speed to

between 2500 and 2700 rpm. With the engine
held at this speed, make sure that the damper
plunger is just touching the throttle stop pin. If
not, loosen the locknut and adjust the position
of the damper as necessary. Tighten the

locknut after making the adjustment.

25 Increase the engine speed to 3000 rpm,
then use a stopwatch to check that it takes
between 3 and 5 seconds to return to normal

idling speed when the throttle is released.

26 If adjustment is necessary, the retardation
time may be shortened by screwing the

damper away from the throttle, or lengthened
by screwing the damper towards the throttle.

Removal

27 Unscrew the locknut, and remove the

damper from the bracket on the throttle
housing.

Refitting

28 Refitting is a reversal of removal, but
adjust it with reference to paragraphs 22 to 26.

Evaporative emission canister and
purge valve

Testing

29 If the system is thought to be faulty, first
follow the procedure given in paragraphs 30 to

32 Check that the hoses from the charcoal
canister and purge control valve are clear by
blowing through them. If the purge control
valve or charcoal canister are thought to be

faulty, they must be renewed.

Removal

30 Apply the handbrake, then jack up the

front of the car and support on axle stands

(see "Jacking, towing and wheel changing").
Remove the right-hand front wheel.

31 Remove the right-hand front wing plastic

moulding, followed by the front section of the
wheelarch liner.
32 Identify the positions of the hoses on the
canister, then disconnect them (see
illustration).

33 Unhook the canister from its mounting
bracket and remove from under the wing.
34 Disconnect and remove the purge valve,
noting that the arrow points towards the
connector end of the canister (see
illustration).

Refitting

35 Refitting is a reversal of the removal

procedure, but make sure that the hoses are
reconnected to their original positions, and

that the purge valve arrow points in the correct
direction.

Catalytic converter
Testing

36 The performance of the catalytic converter
can be checked only by measuring the
exhaust gases using a good-quality, carefully-
calibrated exhaust gas analyser as described
in Chapter 1.
37 If the CO level at the tailpipe is too high,
the vehicle should be taken to a Saab dealer

so that the fuel injection and ignition systems,
including the lambda sensor, can be

thoroughly checked using special diagnostic
equipment. Once these have been checked
and are known to be free from faults, the fault

must be in the catalytic converter, which must
be renewed as described in Part A of this

Chapter.
38 A temperature sensor is incorporated in
the catalytic converter on some models,
together with a warning light on the instrument
panel.

Removal and refitting

39 Removal and refitting of the catalytic
converter is described in Chapter 4A, as part
of the exhaust system procedures.

Catalytic converter temperature

sensor

Removal

40 To remove the temperature sensor, first

push the right-hand front seat fully forwards,

then disconnect the sensor wiring plug.
41 Tie a piece of string to the wiring, as an aid
to refitting.
42 Apply the handbrake, then jack up the car
and support on axle stands (see "Jacking,
towing and wheel changing").
43 Unbolt and remove the heat shield from

beneath the catalytic converter.

2.32 Evaporative emissions canister (A) and
hoses (B) beneath the right-hand front wing

2.34 Purge valve location on the

evaporative emissions canister

4B•4 Emissions control systems

1 The catalytic converter is a reliable and
simple device which needs no maintenance in
itself, but there are some facts of which an
owner should be aware if the converter is to

function properly for its full service life.

a) DO NOT use leaded petrol in a car with a

catalytic converter - the lead will coat the

precious metals, reducing their converting

efficiency, and may eventually destroy the
converter.

b) Always keep the ignition and fuel systems

well-maintained in accordance with the

manufacturer's schedule (see Chapter 1).

c) If the engine develops a misfire, do not

drive the car at all (or at least as little as

possible) until the fault is cured.

d) DO NOT push- or tow-start the car - this

will soak the catalytic converter in
unbumed fuel, causing it to overheat when
the engine does start.

e) DO NOT switch the engine off at high

engine speeds - ie do not "blip" the

throttle before switching off. Allow it to

return to idle first.

f) DO NOT use fuel or engine oil additives -

these may contain substances harmful to
the catalytic converter.

g) DO NOT continue to use the car if the

engine burns oil to the extent of leaving a
visible trail of blue smoke.

h) Remember that the catalytic converter

operates at very high temperatures. DO
NOT, therefore, park the car in dry
undergrowth, over long grass, or over

piles of dead leaves, after a long run.

i) Remember that the catalytic converter is

FRAGILE - do not strike it with tools
during servicing work.

44 Unscrew the sensor from the catalytic
converter, then pull the wiring through the floor
and untie the string. Leave the string in place,
to pull the wiring back through on refitting.

Refitting

45 Refitting is a reversal of removal, using the
string to pull the wiring through the floor.

5A•1

Chapter 5 Part A:

Starting and charging systems

Contents

Alternator - removal and refitting 7
Alternator brushes and regulator - inspection and renewal 8
Alternator drivebelt - removal, refitting and tensioning 6

Battery - removal and refitting 4
Battery - testing and charging 3
Battery check See Chapter 1

Charging system - testing 5

Electrical fault-finding - general information 2
Electrical system check See Chapter 1
General information and precautions 1
Ignition switch - removal and refitting 12
Starter motor - brush renewal 11

Starter motor - removal and refitting 10
Starting system - testing 9

Specifications

System type 12-volt, negative earth

Battery

T

ype

Battery capacity
Charge condition:

Poor
Normal
Good .

Lead-acid, "low-maintenance" or "maintenance-free" (sealed for life)
60/62 amp/hr

12.5 volts
12.6 volts
12.7 volts

Alternator

Type Bosch

Output current 70, 80 or 115 amps

Minimum brush protrusion from holder 5.0 mm
Minimum slip ring diameter:

70

and

80

amp 26.8

mm

115 amp 27.2

mm

Starter motor

~ype Bosch

Output 1.4 kW

Torque wrench settings Nm lbf ft

Starter solenoid to starter 5 4
Starter through-bolts 3 2

General information

Because of their engine-related functions,

the components of the starting and charging

systems are covered separately from the body

electrical devices such as the lights,

instruments, etc (which are covered in Chapter

12). Refer to Part B of this Chapter for

information on the ignition system.

The electrical system is of the 12-volt

negative earth type.

The battery fitted as original equipment is of

low-maintenance or "maintenance-free"
(sealed for life) type. The battery is charged by

the alternator, which is belt-driven from the
crankshaft pulley. During the life of the car, the
original battery may have been replaced by a
standard type battery.

The starter motor is of the pre-engaged

type, incorporating an integral solenoid. On
starting, the solenoid moves the drive pinion
into engagement with the flywheel/driveplate

ring gear before the starter motor is energised.
Once the engine has started, a one-way clutch
prevents the motor armature being driven by

the engine until the pinion disengages from the

ring gear. Unlike some modern starter motors,
it incorporates epicyclic reduction gears
between the armature and the pinion.

Precautions

Further details of the various systems are

given in the relevant Sections of this Chapter.
While some repair procedures are given, the
usual course of action is to renew the

Degrees of difficulty