SAAB 9000. Instruction - page 25

4A•10 Fuel and exhaust systems
wiring loom lead in the engine compartment.
Also check that battery voltage is present at
one of the terminals for fuse 14. Check the
wiring if voltage is not present.
3 Remove the glovebox with reference to
Chapter 11, then remove the fuse panel
(without disconnecting the wiring) with
reference to Chapter 12.
4 Using a voltmeter, check that battery
voltage is reaching terminal 30 on the panel.
5 Check that voltage is reaching terminal 87
on the fuel pump relay. If not, check the wiring
for a fault. If all else is in good order, renew the
relay.
Trionic engine management system
6 The fuel pump relay is located in the relay
holder on the left-hand side of the facia.
Switch on the ignition, and listen for a buzzing
sound from the relay. Also listen for a buzzing
sound from the fuel pump in the fuel tank
below the rear luggage compartment.
7 If neither the relay nor the pump can be
heard, check fuse 14 in the fusebox. If this is in
order, remove the relay from the holder, and
connect an LED tester to terminals 85 and 86
in the holder. With the ignition switched on,
the tester should flash, proving that current is
reaching the relay. If current is reaching the
relay, but the pump is not running, the relay is
suspect, and a new one should be fitted.
8 If the relay can be heard to click when
current is supplied, connect a jumper lead
across fuses 14 and 22 in the f usebox. The
pump should now be receiving current. If the
pump still refuses to operate, check for current
at the pump wiring under the rear luggage
floor. If the pump is receiving current but still
refuses to operate, it must be faulty.
Renewal
9 To renew the relay, pull it direct from the
relay panel.
10 Push the new relay firmly into the relay
panel.
Note: Refer to the warning note at the end of
Section 1 before proceeding.
Removal
1 Disconnect the battery negative lead.
2 For access to the sender unit, fold the rear
seat cushions forward (where necessary).
3 Remove the luggage compartment floor
panel, then remove the cover from over the
fuel tank by turning the fasteners a quarter-
turn, using an Allen key.
4 Disconnect the wiring plugs from the fuel
gauge sender unit, noting their fitted positions.
5 The unit is secured by a screw cap. Saab
technicians use a special tool to unscrew the
cap, but a large pair of grips will achieve the
same result.
6 Withdraw the sender unit from the top of the
fuel tank, taking care not to spill fuel onto the
interior of the car. Recover the rubber sealing
ring. Check the sealing ring, and if necessary
obtain a new one.
Refitting
7 Refitting is a reversal of the removal
procedure.
Note: Refer to the warning note at the end of
Section 1 before proceeding.
Removal
1 Before removing the fuel tank, it is
preferable that all the fuel is removed from the
tank. Since a fuel tank drain plug is not
provided, carry out the removal operation
when the tank is nearly empty. If it is not
possible to syphon or hand-pump the
remaining fuel from the tank, use the following
procedure. Remove the luggage compartment
floor panel and the cover from the fuel pump,
then disconnect the wiring from the pump.
Disconnect the delivery hose from the pump,
and connect a suitable plastic tube to the
pump using a banjo union. Position the free
end of the plastic tube in a suitable container.
Remove fuses 14 and 22 from the f usebox
with reference to Chapter 12, then connect a
bridging wire between the two terminals to
start the fuel pump. Pump all of the fuel out of
the tank, then reconnect all components. Keep
the fuel in a safe place, observing the
precautions given in Section 1.
2 Disconnect the battery negative lead.
3 Remove the rear luggage compartment floor
panels, and the cover from the fuel pump
(using an Allen key).
4 Disconnect the fuel lines and wiring from the
fuel pump.
5 Chock the front wheels, then jack up the
rear of the car and support on axle stands (see
"Jacking, towing and wheel changing"). Make
sure that the stands will not obstruct the
removal of the tank. Remove the right-hand
rear wheel.
6 Loosen the clips and disconnect the inlet
hose from the tank. Also disconnect the
breather hose.
7 Working beneath the car, detach the
handbrake cable (refer to Chapter 9).
8 Support the weight of the fuel tank using a
trolley jack with an interposed block of wood,
then unscrew the tank mounting nuts. Start
with the right-hand mounting, so that the
handbrake cable can be tied to one side.
Remove both mounting straps.
9 With the help of an assistant, lower the fuel
tank and remove it from under the car.
10 If the tank is contaminated with sediment
or water, remove the sender unit (models with
LH-Jetronic fuel injection - Section 12) and
swill the tank out with clean fuel. In certain
cases, it may be possible to have small leaks
or minor damage repaired. Seek the advice of
a suitable specialist before attempting to
repair the fuel tank.
Refitting
11 Refitting is the reverse of the removal
procedure, noting the following points:
a) When lifting the tank back into position,
make sure that the mounting straps are
correctly positioned, and take great care
to ensure that none of the hoses become
trapped between the tank and vehicle
body.
b) Ensure that all pipes and hoses are
correctly routed, and securely held in
position with their retaining clips.
c) When refitting the anti-splash device,
make sure that the butterfly spindle is
vertical.
d) On completion, refill the tank with fuel,
and check for signs of leakage prior to
taking the vehicle out on the road.
Testing
1 If a fault appears in the fuel injection system,
first ensure that all the system wiring
connectors are securely connected and free of
corrosion. Then ensure that the fault is not due
to poor maintenance - ie, check that the air
cleaner filter element is clean, the spark plugs
are in good condition and correctly gapped,
the cylinder compression pressures are
correct, the ignition timing is correct (where
this is adjustable), and that the engine
breather hoses are clear and undamaged,
referring to Chapters 1, 2 and 5 for further
information.
2 If these checks fail to reveal the cause of the
problem, the car should be taken to a Saab
dealer for testing. A diagnostic connector is
incorporated in the wiring circuit, into which a
Saab special electronic diagnostic tester can
be plugged. The tester will locate the fault
quickly and simply, alleviating the need to test
all the system components individually.
Checking and adjustment
3 The following adjustments are only
possible on certain models fitted with the
LH-Jetronic fuel injection system. The idle
speed may be adjusted on engines not fitted
with idle control, and the idle mixture may be
adjusted on engines not fitted with a catalytic
converter. On models with the Trionic engine
management system, the idle speed and
mixture are automatically controlled by the
ECU. The checking of idle speed and mixture
is possible on all models by using a
tachometer and exhaust gas analyser, but
some difficulty may be experienced
connecting a conventional tachometer to the
engine on cars fitted with Direct Ignition. Most

Fuel and exhaust systems 4A•11
models are in fact fitted with an engine
tachometer on the instrument panel.
4 Before checking and adjusting the idle
speed or mixture settings, always check the
following first:
a) Check the ignition timing (models with
Hall-effect ignition) (Chapter 5B).
b) Check that the spark plugs are in good
condition and correctly gapped (Chapter 1).
c) Check that the accelerator cable is
correctly adjusted (Section 3).
d) Check that the crankcase breather hoses are
secure, with no leaks or kinks (Chapter 1).
e) Check that the air cleaner filter element is
clean (Chapter 1).
f) Check that the exhaust system is in good
condition (Chapter 1).
g) If the engine is running very roughly,
check the compression pressures
(Chapter 2A).
5 Take the car on a journey of sufficient length
to warm the engine to normal operating
temperature. Note: Checking/adjustment
should be completed as soon as possible so
that the engine is still at its normal operating
temperature. If the radiator electric cooling fan
operates, first wait for the cooling fan to stop.
Clear any excess fuel from the inlet manifold
by racing the engine two or three times to
between 2000 and 3000 rpm, then allow it to
idle again.
6 Ensure that all electrical loads are switched
off, then stop the engine and connect a
tachometer to it, following its manufacturer's
instructions. Where a tachometer is fitted to
the instrument panel, this may be used instead.
If the idle mixture is to be checked, connect an
exhaust gas analyser in accordance with its
manufacturer's instructions.
Models with LH-Jetronlc fuel
injection (except models with idle
air control and catalytic converter)
7 The idle speed adjustment screw is located
on the throttle housing. Start the engine and
allow it to idle, then check that the idle speed
is as given in the Specifications. If adjustment
is necessary, loosen the locknut. Adjust the
screw in to reduce the speed, or out to
increase the speed. Tighten the locknut after
making the adjustment.
8 The idle mixture adjustment screw is
located on the airflow meter, and may be
hidden under a tamperproof cap. First remove
the cap. With the engine idling at the correct
idling speed, check that the CO level is as
given in the Specifications. If adjustment is
necessary, use an Allen key or screwdriver to
turn the mixture adjustment screw in or out (in
very small increments) until the CO level is as
given in the Specifications. Turning the screw
in (clockwise) richens the mixture and
increases the CO level, turning it out will
weaken the mixture and reduce the CO level.
9 If necessary, readjust the idle speed.
10 Temporarily increase the engine speed,
then allow it to idle and recheck the settings.
11 When adjustments are complete, stop the
engine and disconnect the test equipment.
Other models with LH-Jetronic
and Trionic systems
12 The idle speed is controlled by an idle air
control valve, in conjunction with the system
ECU. With the engine at normal operating
temperature, check that the idle speed is as
given in the Specifications. No adjustment is
possible.
13 The idle mixture is controlled by the
lambda sensor, in conjunction with the system
ECU. With the engine at normal operating
temperature, check that the idle mixture is as
given in the Specifications. No adjustment is
possible.
14 If incorrect readings are obtained, take the
car to a Saab dealer and have the system
checked with the special tester.
Electronic control unit
Removal
1 Disconnect the battery negative lead.
2 With the bonnet open, remove the cover
behind the bulkhead panel on the left-hand
side of the engine compartment.
3 Unscrew the mounting screws, and
withdraw the electronic control unit from the
bulkhead.
4 Release the clip and disconnect the multi-
plug connector from the ECU.
Refitting
5 Refitting is a reversal of the removal
procedure.
Coolant temperature sensor
Removal and refitting
6 The procedure is described in Chapter 3,
Section 6.
Throttle position switch
Removal
7 Disconnect the wiring plug from the throttle
position switch on the throttle housing (see
illustration).
8 Mark the position of the switch on the
throttle housing.
9 Unscrew the mounting screws and remove
the switch.
Refitting and adjustment
10 Refit the switch to the throttle housing,
and insert the mounting screws finger-tight.
11 If the original switch is being refitted, align
the previously-made marks and tighten the
screws.
12 If there is any doubt that the throttle
housing butterfly valve stop position is
incorrect, loosen the locknut and back off the
adjustment screw until it is clear of the stop.
Now screw it in until it just touches the stop.
Turn the screw in a further quarter-turn, and
lock it in this position.
13 With the throttle valve at its rest position,
turn the throttle position switch until it touches
the internal stop for the idling position, then
tighten the mounting screws.
14 Connect a ohmmeter to the terminals on
the switch. With the throttle valve at its rest
position, the meter should register zero ohms
(ie continuity). Open the throttle valve, and
check that the internal contacts open
immediately the throttle is moved. With the
throttle valve close to the fully-open position
(72° from rest position), the internal contacts
should close again.
Throttle housing
Removal
15 Referring to Chapter 1, drain off
approximately 2 litres of coolant, so that the
coolant level is below the throttle housing.
16 Loosen the clip and disconnect the air
inlet hose from the throttle housing (see
illustration).
17 Disconnect the accelerator cable, and
remove it from the throttle housing - refer to
Section 3.
18 Disconnect the wiring plug from the
throttle position switch.
19 Loosen the clips and disconnect the
coolant hoses (see illustration). Plug the
hoses to prevent loss of coolant.
20 On 1985 models only, disconnect the air
hoses from the auxiliary air valve.
4A
15.7 Disconnecting the wiring plug from
the throttle position switch
15.16 Loosen the clip and disconnect the
air inlet hose from the throttle housing

4A•12 Fuel and exhaust systems
15.19 Coolant hoses (A) and vacuum
hose (B) on the throttle housing
15.23 One of the mounting nuts securing
the throttle housing to the inlet manifold
21 Where necessary, remove the turbo Removal
pressure (discharge) pipe.
22 Disconnect the vacuum hose from the
throttle housing.
23 Unscrew the three mounting nuts and
remove the throttle housing from the inlet
manifold (see illustration).
Refitting
24 Refitting is a reversal of the removal
procedure. On completion, check and if
necessary adjust the throttle position switch
and the accelerator cable. Top-up the cooling
system with reference to Chapter 1.
Airflow meter
Removal
25 Loosen the clips and disconnect the hoses
from each end of the airflow meter.
26 Disconnect the wiring multi-plug from the
airflow meter (see illustration).
27 Release the toggle spring clips, then lift
the airflow meter assembly from the air cleaner
lower body.
Refitting
28 Refitting is a reversal of the removal
procedure, but align the slot with the air
cleaner body.
Fuel supply rail and injectors
Note: Refer to the warning at the end of
Section 1 before proceeding.
15.32 The connector (arrowed) for the fuel
supply line at the supply rail
Note: If a faulty injector is suspected, before
condemning the injector, it is worth trying the
effect of one of the proprietary injector-
cleaning treatments.
29 Clean the area surrounding the fuel supply
rail, to prevent entry of dust and dirt into the
fuel system.
30 Unbolt and remove the false bulkhead at
the rear of the engine compartment.
31 Loosen the clip and disconnect the fuel
return hose from the fuel pressure regulator -
anticipate loss of fuel by placing a cloth
beneath the regulator. Also disconnect the
vacuum hose from the regulator. On some
early models, the fuel pressure regulator may
be located on a bracket secured to the
cylinder head.
32 Unscrew the connector, and disconnect
the fuel supply line for the supply rail (see
illustration).
33 Disconnect the wiring plugs from the
injectors.
34 Unscrew the mounting bolts, and
withdraw the supply rail from the inlet
manifold. Do not remove the injectors from the
rail at this stage.
35 Remove the rubber O-rings from the inlet
manifold.
36 Withdraw the fuel supply rail through the
space between the inlet manifold and the
bulkhead.
37 To remove the injectors from the rail,
remove the clips and pull out the injectors.
Refitting
38 Refitting is a reversal of the removal
procedure. Before locating the rubber
O-rings in the inlet manifold, apply a little
petroleum jelly to them, to facilitate entry of
the injectors.
Fuel pressure regulator
Note: Refer to the warning at the end of
Section 1 before proceeding.
Removal
39 Clean the area surrounding the fuel
pressure regulator, to prevent entry of dust
and dirt into the fuel system.
15.26 Airflow meter wiring plug
40 Unbolt and remove the false bulkhead at
the rear of the engine compartment.
41 Loosen the clip and disconnect the
fuel return hose from the fuel pressure
regulator - anticipate loss of fuel by
placing a cloth beneath the regulator. Also
disconnect the vacuum hose from the
regulator.
42 Unscrew the mounting bolts, and
withdraw the supply rail from the inlet manifold
sufficiently to gain access to the fuel pressure
regulator.
43 Unbolt the regulator from the inlet
manifold.
44 Unscrew the regulator from the bracket.
Refitting
45 Refitting is a reversal of removal
Auxiliary air valve
Removal
46 Disconnect the wiring plug from the
auxiliary air valve.
47 Loosen the clips and disconnect the two
hoses from the valve.
48 Unscrew the mounting bolts and remove
the auxiliary air valve from the engine.
Refitting
49 Refitting is a reversal of removal.
Pressure switch (Turbo models)
Removal
50 Working under the facia on the left-hand
side, unscrew the screws and remove the
lower cover.
51 Remove the APC mounting panel.
52 Loosen the clips and disconnect the
hoses, then remove the pressure switch.
Refitting
53 Refitting is a reversal of removal.
Automatic idle control (AIC) valve
(B2O2 models)
Removal
54 The automatic idle control is located

Fuel and exhaust systems 4A•13
15.54 Automatic idle control on B2O2
models
15.55 Disconnecting the wiring plug from
the idle air control valve
15.57 Idle air control valve mounting bolts
centrally over the inlet manifold (see
illustration).
55 Disconnect the wiring plug (see
illustration).
56 Loosen the clips and disconnect the
hoses.
57 Unscrew the retaining bolts, then slide the
valve from the clip (see illustration).
Refitting
58 Refitting is a reversal of removal.
Cold start injector
Removal
59 A cold start injector is fitted to certain
models. It is located on top of the inlet
manifold.
60 Disconnect the wiring plug (see
illustration).
61 Unscrew the union bolt, and disconnect
the fuel supply from the injector
62 Unscrew the mounting bolts, and remove
the injector from the inlet manifold. Recover
the gasket.
Refitting
63 Refitting is a reversal of removal, but
renew the gasket.
Control module
Removal
1 With the ignition switched off, remove the
cover from the false bulkhead.
2 Unscrew the bolt and disconnect the control
module earth cable from the bulkhead (see
illustration).
3 Release the clip then lift the control module
from its mounting (see illustration).
4 Pull up the plastic cover, then unhook and
release the multi-plug connector from the
control module (see illustration). Remove the
module from the bulkhead.
Refitting
5 Refitting is a reversal of removal. Make sure
that the correct module is fitted, and give the
car a road test to check for operation.
Inlet air temperature sensor
Removal
6 Disconnect the wiring from the sensor,
which is located in the main air inlet duct to
the throttle housing.
15.64 Disconnecting the wiring plug from
the cold start injector
7 Unscrew the sensor from the air inlet duct,
and recover the sealing washer.
Refitting
8 Refitting is a reversal of removal, but check
and if necessary renew the sealing washer.
Manifold absolute pressure (MAP)
sensor
Removal
9 Lift the weathestrip from the right-hand
side of the false bulkhead.
10 Disconnect the wiring plug and vacuum
hose, then lift the sensor from the false
16.2 Unbolting the earth cable from the
bulkhead
16.3 Lifting the control module from its
mounting
16.4 Disconnecting the multi-plug
connector from the module