SAAB 9000. Instruction - page 26

4A•14 Fuel and exhaust systems
16.10 Removing the manifold absolute
pressure (MAP) sensor
16.22c Removing the crankshaft position
sensor
bulkhead and remove it (see illustration). If
necessary, unscrew the mounting screws, and
separate the sensor from the mounting
bracket.
Refitting
11 Refitting is a reversal of removal.
Engine coolant temperature
sensor
Removal
12 The sensor is located on the inlet manifold
lower section. First drain the cooling system
as described in Chapter 1.
13 Remove the upper inlet manifold with
reference to Section 20.
14 Disconnect the wiring connector from the
sensor.
15 Unscrew the sensor from the lower inlet
manifold.
Refitting
16 Clean the threads, then insert the sensor
in the lower inlet manifold, and tighten
securely.
17 Refit the connector.
18 Refit the upper inlet manifold with
reference to Section 20.
19 Refill the cooling system with reference to
Chapter 1.
Crankshaft position sensor
(non-turbo engine)
Removal
20 Remove the upper and lower sections of
16.22a Crankshaft position sensor wiring
support clip (arrowed) on the left-hand end
of the engine
the inlet manifold, with reference to Sec-
tion 20.
21 Note the routing of the wiring for the
crankshaft position sensor. Disconnect the
wiring at the connector located below the inlet
manifold. Note that access is very limited.
22 Release the wiring from the plastic cable-
ties, and unscrew the support clips from the
left-hand end of the engine. Remove the
retaining screw and remove the sensor from
its location on the front left-hand side of the
cylinder block (see illustrations). Recover the
O-ring, noting how it is fitted. Clean the
seating in the cylinder block.
Refitting
23 Refitting is a reversal of removal, but
tighten the sensor to the specified torque.
Crankshaft position sensor
(turbo engine)
Removal
24 Disconnect the crankshaft position sensor
wiring plug, located below the inlet manifold.
Note that access is restricted.
25 Release the wiring from the plastic cable-
ties, then unscrew the retaining screw and
remove the sensor from its location on the
front left-hand side of the cylinder block.
Recover the O-ring, noting how it is fitted.
Clean the seating in the cylinder block.
Refitting
26 Refitting is a reversal of removal, but
tighten the sensor to the specified torque.
Throttle position sensor
(not Electronic Throttle System)
Removal
27 The throttle position sensor is located on
the throttle housing on the left-hand end of the
inlet manifold.
28 Disconnect the wiring plug from the
sensor.
29 Disconnect the large crankcase ventilation
hose from the throttle housing
30 Unscrew the retaining screws, and remove
the sensor from the housing. Remove the O-
ring from the throttle spindle. Examine the
O-ring, and obtain a new one if necessary.
16.22b Crankshaft position sensor location
Refitting
31 Refitting is a reversal of removal.
Idle air control valve
(B2O4/B234 models without turbo)
Removal
32 The idle air control valve is located
beneath the upper section of the inlet
manifold. First disconnect the battery negative
lead.
33 Disconnect the inlet hose from the throttle
housing, and disconnect the wiring plug from
the throttle position sensor.
34 Disconnect the crankcase ventilation hose
from the throttle housing, and also disconnect
the idle air control valve hose (under the
throttle housing).
35 Using hose clamps, clamp the coolant
hoses connected to the throttle housing.
Careful use of grips and suitable packing will
also achieve the same result. Loosen the clips
and disconnect the hoses from the throttle
housing.
36 Detach the accelerator cable (and where
applicable, the automatic transmission
kickdown cable).
37 Disconnect the fuel pressure regulator and
crankcase ventilation vacuum hoses from the
inlet manifold.
38 Disconnect the evaporative control
canister-purge hose from the inlet manifold,
then unscrew the outer screws from the inlet
manifold.
39 Unscrew and remove the bolts from the oil
filler pipe bracket.
40 Disconnect the manifold absolute
pressure sensor hose.
41 Remove the upper section of the inlet
manifold, then turn it over and disconnect the
wiring plug from the idle air control valve.
42 Loosen the clips and disconnect the
hoses.
43 Detach the idle air control valve from its
mounting.
Refitting
44 Refitting is a reversal of removal, but
adjust the accelerator cable (and where
applicable, the automatic transmission
kickdown cable) with reference to Section 3 of
this Chapter and Chapter 7B.

Fuel and exhaust systems 4A•15
16.54a Removing a plastic locating rail
(arrowed) from the injectors
Idle air control (IAC) valve
(B2O4/B234 Turbo models, non-
ETS engines)
Removal
45 Loosen the clips and disconnect the air
duct from the throttle housing.
46 Prise out the circlip, and move the
accelerator cable to one side.
47 On automatic transmission models,
disconnect the kickdown cable with reference
to Chapter 7B.
48 Loosen the clips and disconnect the idle
air control valve hoses from the throttle
housing.
49 Remove the valve from the mounting
bracket, and disconnect the wiring pug.
50 Disconnect the hoses from the valve.
Refitting
51 Refitting is a reversal of removal, but delay
fully tightening the hose clips until the valve is
positioned correctly.
Fuel supply rail and Injectors
(normally-aspirated engine)
Note: Refer to the warning at the end of
Section 1 before proceeding.
Removal
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.
52 Remove the upper section of the inlet
manifold as described in Section 20.
53 Clean the area around the injectors and
fuel connections to prevent entry of dust and
dirt into the fuel system.
54 Remove the plastic locating rails, and
disconnect the wiring plugs from the injectors.
Note that the plug wiring is marked for position
according to cylinder (see illustrations).
55 Depressurise the fuel system with
reference to Section 9. Place a cloth beneath
the fuel rail, to soak up fuel which will escape
as the fuel rail is removed.
56 Unscrew the mounting screws, and lift out
the fuel rail complete with the injectors.
57 Prise out the retaining clips, and pull the
injectors from the fuel rail.
16.54b The injector wiring is marked
according to the cylinder
Refitting
58 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.
Make sure that the correct wiring plugs are
attached to the injectors.
Fuel supply rail and Injectors
(Turbo engine)
Note: Refer to the warning at the end of
Section 1 before proceeding.
Removal
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.
59 Depressurise the fuel system with
reference to Section 9. Place a cloth beneath
the fuel rail, to soak up fuel which will escape
as the fuel rail is removed.
60 Unscrew the fuel rail mounting screws,
and lift off the rail together with the injectors.
61 Remove the locating rails, and disconnect
the wiring plugs from the injectors. Note that
the plugs are marked for position.
62 Prise out the retaining clips, and pull the
injectors from the fuel rail.
Refitting
63 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.
Make sure that the correct wiring plugs are
attached to the injectors.
Throttle housing
Note: The following paragraphs describe
removal and refitting procedures for models
not fitted with the Electronic Throttle System
(as fitted to models with traction control),
although the procedure will be very similar.
Refer to Section 6 if necessary.
Removal
64 Loosen the clip, and disconnect the rubber
connecting hose from the throttle housing.
65 Disconnect the wiring plug from the
throttle position sensor.
66 With the engine cold, unscrew the filler
16.54c Disconnecting the injector wiring
plugs
cap on the coolant expansion tank, then refit
and tighten the cap.
67 Loosen the clips, then disconnect and
plug the coolant hoses from the throttle
housing.
68 Disconnect the crankcase breather hose
from the throttle housing.
69 Disconnect the IAC valve hose from the
throttle housing.
70 Disconnect the accelerator cable (and
where necessary, the cruise control cable)
with reference to Section 3.
71 On automatic transmission models,
disconnect the kickdown cable with reference
to Chapter 7B.
72 Unscrew the mounting nuts, and remove
the throttle housing from the inlet manifold.
Recover the O-ring.
Refitting
73 Clean the contact surfaces of the throttle
housing and inlet manifold, then refit the
throttle housing together with a new O-ring.
Tighten the mounting bolts.
74 On automatic transmission models,
reconnect and adjust the kickdown cable with
reference to Chapter 7B.
75 Reconnect and adjust the accelerator
cable (and where necessary, the cruise control
cable) with reference to Section 3.
76 Reconnect the IAC valve hose and the
crankcase breather hose.
77 Reconnect the coolant hoses and tighten
the clips.
78 Reconnect the wiring plug to the throttle
position sensor.
79 Reconnect the rubber connecting hose to
the throttle housing, and tighten the clip.
80 Top-up the cooling system with reference
to Chapter 1.
4A
Description
1 The turbocharger fitted to certain models
increases engine efficiency by raising the
pressure in the inlet manifold above
atmospheric pressure. Instead of the air
simply being sucked into the cylinder, it is
forced in.

4A•16 Fuel and exhaust systems
2 Energy for the operation of the turbocharger
comes from the exhaust gas. The gas flows
through a specially-shaped housing (the
turbine housing) and in so doing, spins the
turbine wheel. The turbine wheel is attached to
a shaft, at the end of which is another vaned
wheel, known as the compressor wheel. The
compressor wheel spins in its own housing,
and compresses the inlet air on the way to the
inlet manifold.
3 Between the turbocharger and the inlet
manifold, the compressed air passes through
an intercooler. This is an air-to-air heat
exchanger, mounted in front of the radiator.
The purpose of the intercooler is to remove
from the inlet air some of the heat gained in
being compressed. Because cooler air is
denser, removal of this heat further increases
engine efficiency.
4 Boost pressure (the pressure in the inlet
manifold) is limited by a wastegate, which
diverts the exhaust gas away from the turbine
wheel in response to a pressure-sensitive
control valve. In the event of excess pressure
in the inlet manifold (ie if the wastegate
malfunctions), a safety cut-out system will
switch off the fuel pump, and the engine will
stop.
5 On models prior to 1987, the turbocharger
is cooled only by the engine oil. From 1987 on,
it is also water-cooled, in order to reduce the
temperature of the bearing housing
6 All Turbo models are fitted with an
Automatic Performance Control (APC) system.
Its basic purpose is to adjust the ignition
timing and turbocharger operation so that the
engine runs at peak efficiency and economy,
regardless of the quality and octane rating of
fuel being used. This is necessary because
fuels of the same grade can sometimes give
different engine characteristics.
7 On models manufactured up to 1989, the
APC system incorporates its own separate
electronic control unit (ECU), located under
the left-hand side of the facia panel. On this
system, the APC only controls the
turbocharger and not the ignition timing.
8 From 1989 to 1993, the APC system is
incorporated into the Direct Ignition ECU
located beneath the left-hand front seats.
From 1994 onwards, the system is
incorporated into the Trionic engine
management ECU, located behind the engine
compartment false bulkhead on the left-hand
side. On both the latter systems, the ignition
timing is retarded as and when necessary in
addition to the control of the turbocharger.
The APC system monitors the onset of pre-
ignition ("pinking" or "knocking") in the engine
by means of a knock detector. Also included in
the system is a pressure transducer (which
monitors pressure in the inlet manifold) and a
solenoid valve (which controls the
turbocharger wastegate).
9 The turbo shaft is pressure-lubricated by an
oil feed pipe from the main oil gallery. The
shaft "floats" on a cushion of oil. A drain pipe
returns the oil to the sump.
Precautions
10 The turbocharger operates at extremely
high speeds and temperatures. Certain
precautions must be observed, to avoid
premature failure of the turbo, or injury to the
operator.
11 Do not operate the turbo with any of its
parts exposed, or with any of its hoses
removed. Foreign objects falling onto the
rotating vanes could cause excessive
damage, and (if ejected) personal injury.
12 Do not race the engine immediately after
start-up, especially if it is cold. Give the oil a
few seconds to circulate.
13 Always allow the engine to return to idle
speed before switching it off - do not blip the
throttle and switch off, as this will leave the
turbo spinning without lubrication.
14 Allow the engine to idle for several minutes
before switching off after a high-speed run.
15 Observe the recommended intervals for oil
and filter changing, and use a reputable oil of
the specified quality. Neglect of oil changing,
or use of inferior oil, can cause carbon
formation on the turbo shaft, leading to
subsequent failure.
T3 / TEO5 turbocharger
Removal
1 Apply the handbrake, then jack up the front
of the car and support on axle stands (see
"Jacking, towing and wheel changing").
2 Remove the centre air deflector from
beneath the radiator, then, on models where
the turbocharger is cooled by the coolant (ie
models from 1987 on), drain the cooling
system as described in Chapter 1.
3 Where applicable, remove the air
conditioning compressor drivebelt and
tensioner device.
4 Position a suitable container beneath the oil
cooler, then unscrew the upper union and
unscrew the mounting bolt on the oil cooler.
Position the oil line to one side.
5 Unscrew the air conditioning compressor
mounting bolts, protect the oil cooler with a
piece of cardboard, then lift the compressor
towards the expansion tank. Do not
disconnect the refrigerant lines from the
compressor - refer to the warnings in Chap-
ter 3, Section 10.
6 Disconnect the remove the boost pressure
control valve from its mounting on the fan
cowling, and disconnect the wiring.
7 Disconnect the wiring from the electric
cooling fan motor, then unscrew the bolts and
remove the fan cowling complete with the
radiator fan.
8 Disconnect the wiring from the airflow
meter, then release the toggle clips from the
air cleaner, and disconnect the rubber elbow
from the turbocharger. Remove the airflow
meter.
9 Loosen the clip and disconnect the delivery
(pressure) pipe from the turbocharger.
10 Unscrew the flange bolts and disconnect
the oil supply line from the turbocharger, then
unscrew the oil line clamp bolt from the
cylinder head. Unscrew the oil line banjo union
from the cylinder block, arid release the oil line
from the clamp on the inlet manifold. Remove
the oil line.
11 On models where the turbocharger is
cooled by water, unscrew the union nuts and
disconnect the coolant pipes from the
turbocharger.
12 Unscrew the nuts and disconnect the
exhaust front pipe from the turbocharger.
13 Release the front rubber mountings from
the exhaust pipe.
14 Unbolt and remove the bracket between
the turbocharger and the sump.
15 Unscrew the mounting bolts, and remove
the oil return pipe from the turbocharger and
sump. Recover the gasket and O-ring. Cover
the holes with tape, to prevent entry of dirt and
debris.
16 Unscrew and remove the exhaust
manifold mounting nuts, then lift out the
exhaust manifold from the cylinder head,
complete with the turbocharger unit. Recover
the gasket.
17 Unscrew the nuts, and separate the
turbocharger unit from the exhaust manifold
(see illustration). Note that the nuts have a
special locking flange on them, and should be
renewed whenever removed. New locking
nuts are pre-coated with lubricant. Recover
the gasket.
Refitting
18 Clean the contact surfaces, then locate
the exhaust manifold on the turbocharger
studs with a new gasket, and tighten the new
nuts to the specified torque. The locking
flange on the nuts should face inwards.
19 Clean the contact surfaces, then fit the
exhaust manifold complete with turbocharger
to the cylinder head. Use a new gasket, and
tighten the mounting nuts progressively to the
specified torque.
20 Secure the oil line clamp to the inlet
18.17 Removing the turbocharger from the
exhaust manifold
1 Nut 2 Stud

Fuel and exhaust systems 4A•17
manifold. Check that the copper washers are
in good condition and renew if necessary, then
tighten the banjo union to the cylinder block.
21 Fill the turbocharger inter-chamber with
clean engine oil, through the oil supply union
on the turbocharger. Note: This is important,
as the turbocharger must have oil in it when
the engine is started.
22 Reconnect the oil supply line to the
turbocharger, and tighten the flange bolts.
Refit and tighten the oil line clamp bolt in the
cylinder head.
23 Where applicable, reconnect the coolant
pipes to the turbocharger, and tighten the
union nuts.
24 Refit the oil return pipe to the turbocharger
and sump, together with a new gasket and O-
ring, and tighten the bolts.
25 Refit the front rubber mountings to the
exhaust pipe.
26 Reconnect the exhaust pipe to the
turbocharger, using new locking nuts (the
locking flanges should face outwards).
27 Reconnect the delivery (pressure) pipe to
the turbocharger, and tighten the clip.
28 Refit the airflow meter, and reconnect the
rubber elbow to the turbocharger and air
cleaner. Refit the toggle clips, and reconnect
the wiring to the airflow meter.
29 Refit the electric cooling fan cowling,
complete with the radiator fan, and tighten the
mounting bolts. Reconnect the wiring for the
fan motor.
30 Refit the boost pressure control valve to
its mounting on the fan cowling, and
reconnect the return hose.
31 Where applicable, refit the air conditioning
compressor, and tighten the mounting bolts.
32 Reconnect the oil line to the oil cooler, and
tighten the upper union. Insert and tighten the
mounting bolt on the oil cooler. Remove the
cardboard protector.
33 Refit the air conditioning compressor
tensioner device and drivebelt, and tension the
belt with reference to Chapter 1.
34 Check that the radiator drain plug is tight,
then refit the centre air deflector beneath the
radiator.
35 Lower the car to the ground, then check
and if necessary top-up the engine oil level. It
is strongly recommended that the engine oil is
changed before starting the engine if a new
turbocharger has been fitted, as this will
protect the turbo bearings during the "running-
in" period.
36 On models where the turbocharger is
cooled by coolant, check and if necessary
top-up the cooling system.
37 It is recommended that the basic charging
pressure is checked by a Saab dealer at the
earliest opportunity.
T25 / TDO4 turbocharger
Removal
38 Apply the handbrake, then jack up the
front of the car and support on axle stands
(see "Jacking, towing and wheel changing").
39 Remove the centre air deflector from
beneath the radiator, then drain the cooling
system as described in Chapter 1.
40 Disconnect the remove the boost pressure
control valve from its mounting on the fan
cowling, and disconnect the wiring.
41 Disconnect the wiring from the electric
cooling fan motor, then unscrew the bolts and
remove the fan cowling complete with the
radiator fan.
42 Release the lambda sensor wiring from the
retaining clips.
43 Unscrew the nuts and disconnect the
exhaust front pipe from the turbocharger.
44 Loosen the clips and disconnect the air
hose between the turbocharger and airflow
meter.
45 Loosen the clips and disconnect the short
hose between the coolant pipe and the
turbocharger.
46 Unscrew the union bolts, and remove the
coolant pipe between the turbocharger and
water pump.
47 Where applicable, unscrew the coolant
pipe and oil pipe mounting from the cylinder
head.
48 Unscrew the union bolt, then detach the
oil line from the turbocharger and position it to
one side.
49 Unscrew the union bolts, and remove the
coolant pipe between the turbocharger and
the cylinder head.
50 Release the clips and disconnect the
boost pressure control valve hoses from the
turbocharger and wastegate.
51 Loosen the clip and disconnect the
delivery (pressure) pipe from the turbocharger.
52 Unbolt and remove the bracket between
the turbocharger and sump (B2O2 engine) or
cylinder block (B2O4/B234 engines).
53 Unscrew the mounting bolts, and remove
the oil return pipe from the turbocharger and
sump/block. Recover the gasket and O-ring.
Cover the holes with tape, to prevent entry of
dirt and debris.
54 Unscrew the mounting nuts, and withdraw
the turbocharger from the exhaust manifold.
Recover the gasket. Remove the turbocharger
from the engine compartment.
Refitting
55 Clean the contact surfaces, then refit the
turbocharger to the exhaust manifold, together
with a new gasket. Tighten the mounting nuts
to the specified torque.
56 Refit the oil return pipe to the turbocharger
and sump/block, together with a new gasket
and O-ring, and tighten the bolts.
57 Refit the bracket between the
turbocharger and sump (B2O2 engine) or
cylinder block (B2O4/B234 engines), and
tighten the bolts.
58 Apply a little anti-seize compound to the
studs on the turbocharger, then refit the
exhaust front pipe and tighten the mounting
nuts to the specified torque.
59 Reconnect the delivery (pressure) pipe and
tighten the clips.
60 Reconnect the boost pressure control
valve hoses to the turbocharger and
wastegate.
61 Refit the coolant pipe between the
turbocharger and the cylinder head, and
tighten the union bolts.
62 Fill the turbocharger inter-chamber with
cjean engine oil, through the oil supply union
on the turbocharger. Note: This is important,
as the turbocharger must have oil in it when
the engine is started.
63 Refit the oil supply line to the
turbocharger, and tighten the union bolt.
64 Where applicable, refit the coolant pipe
and oil pipe mountings to the cylinder head.
65 Refit the coolant pipe between the
turbocharger and water pump, and tighten the
union bolts.
66 Reconnect the short hose between the
coolant pipe and the turbocharger, and tighten
the clips.
67 Reconnect the air hose between the
turbocharger and airflow meter, and tighten
the clips.
68 Locate the lambda sensor wiring in the
clips.
69 Refit the electric cooling fan cowling,
complete with the radiator fan, and tighten the
mounting bolts. Reconnect the wiring.
70 Refit the boost pressure control valve to
its mounting on the fan cowling, and
reconnect the wiring.
71 Check that the radiator drain plug is tight,
then refit the centre air deflector.
72 Lower the car to the ground, then check
and if necessary top-up the engine oil level. It
is strongly recommended that the engine oil is
changed before starting the engine if a new
turbocharger has been fitted, as this will
protect the turbo bearings during the "running-
in" period.
73 Refill the cooling system with reference to
Chapter 1.
74 It is recommended that the basic charging
pressure is checked by a Saab dealer at the
earliest opportunity.
Removal
1 Remove the radiator as described in
Chapter 3.
2 Where applicable, remove the plastic guard
from under the intercooler.
3 Loosen the clips and disconnect the hoses
from each end of the intercooler.
4 Unscrew and remove the bolts securing the
intercooler to the air conditioning condenser.
5 Remove the upper mounting bracket and
grommets from the studs on the top of the
intercooler and condenser..
6 Move the intercooler away from the front
panel, lift it from its mountings, and withdraw it
from the engine compartment.
4A