Page 281
4. Mount th-e valve in a valve grinding machine and clean
the sealing surface (45°C).
5. Separate and thotoughly clean the valve body and
bearing housing.
Changing the diaphragm (in the car)
1. Remove the heat shield.
MEASURING THE LENGTH OF THE COMPRESSED SPRING
4.
Mark the position of the valve to enable it to be
refitted in the same position.
REMOVING THE HEAT SHIELD
_2.
Remove the diaphragm housing cover.
MARKING THE POSITION OF THE VALVE IN THE CAR
5.
Loosen the lock nut (using a 10 mm ring spanner
and polygrip pliers) and remove the nut, the outer
spring seating, the spring and the inner spring seating.
REMOVING THE DIAPHRAGM HOUSING COVER
3.
Measure and note the compressed length of the
spring (the distance between the outer and inner
spring seatings). Measure the length at two diametrically opposed points and note the mean value.
REMOVING THE LOCK NUT
SA_ft&
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Page 282
11.
CAUTION
Always grip the valve seat when removing the spindle,
nut to avoid damaging the diaphragm.
6.
Fit the diaphragm with the two diaphragm wash-.
ers. Ensure that the inner ridge on the diaphragm
engages the groove in the diaphragm washer.-
Fit two nuts to the outer thread on the valve
spindle and tighten both nuts.
REMOVING THE DIAPHRAGM
12.
FITTING THE NUTS TO THE OUTER THREAD ON THE
SPINDLE
Fit the diaphragm nut and the two other nuts, and
tighten the diaphragm nut. Remove the other two
nuts.
Lubricate the threads with NEVER SEIZE or
MOLYCOTE 1000 to prevent them welding stuck.
7.
Holding the two nuts, undo the. diaphragm nut.
FITTING THE DIAPHRAGM NUT
REMOVING THE DIAPHRAGM NUT WHEREUPON THE TWO
NUTS ARE GRIPPED
13.
8.
9.
10.
Remove the two nuts, the diaphragm nut, the
outer diaphragm washer, the diaphragm and the
inner diaphragm washer.
Clean the diaphragm housing and all dismantled
parts.
Check that the flat washer inside the inner diaphragm washer is in position.
291-14
...
&AMI
Fit the inner spring seating and then align the
valve with the previous markings.
Page 283
TURNING THE VALVE ACCORDING TO THE MARKS
14.
15.
TURNING THE UPPER SPRING SEATING ACCORDING TO
THE MARKS
Fit the spring and the outer spring seating.
Adjust the compressed length of the spring to the
length measured on dismantling (the,basic length
given in the specifications is approximate).
Replace and tighten the lock nut. Grip the outer
spring seating by means of polygrip pliers.
FITTING THE DIAPHRAGM NUT
16.
17.
Fit the gasket and diaphragm ·housing cover.
Fit the heat shield.
Check the charging pressure and adjust as necessary, and then seal the charge pressure regulator.
ADJUSTING THE COMPRESSED SPRING LENGTH
SAMI
291-15
Page 284
Measuring the charging pressure
The charging pressure is measured while the car is being
test driven and is indicated by means of a special pressure gauge connected to the inlet manifold.
1. Connect pressure gauge 83 92 813 between the nipple
on the inlet manifold and the line to the pressure
switch. Run the hose into the passenger compartment
and place the pressure gauge on the left-hand corner
of the instrument panel.
3
S 6298
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S 6297
3RD GEAR, ENGINE SPEED LOWER THAN 1 500 REV/MIN
EQUIPMENT FOR MEASURING THE CHARGING PRESSURE
4. Accelerate at full throttle by pressing the accelerator
down to the floor.
S 6299
DEPRESSING THE ACCELERATOR TO THE FLOOR
5. As the engine speed approaches 3 000 rev/min, apply
the brakes (still keeping the accelerator pressed down)
MEASURING THE CHARGING PRESSURE
2. Warm up the engine properly by driving the car on
the road.
3. To start the test, drive the car in 3rd gear at an engine
speed lower than 1 500 rev/min.
291-16
SA.1'11
Page 285
to put the car under full load at 3 000 rev/min and
note the maximum pressure indicated by the pressure
gauge.
Adjusting the charging pressure
(After test driving)
If the reading on the pressure gauge during test driving
deviates from the specified value, adjustment based on
the readings recorded can be carried out as follows:
1. Remove the heat shield mounted in front of the charge
pressure regulator.
2. Disconnect the exhaust line from the cover on the diaphragm housing cover.
3. Remove the diaphragm housing cover.
.. ...
~
S 6300
APPLYING THE BRAKES WITH THE ACCELE.RATOR DEPRESSED, ENGINE SPEED 3 000 REV/MIN
REMOV~NG THE DIAPHRAGM HOUSING COVER
4. Undo the lock nut using a 10 mm ring spanner. Grip
the spring seating by means of polygrip pliers.
CAUTION
Always grip the valve seat when removing the spindle
nut to avoid damaging the diaphragm. Never attempt
to turn the valve.
THE MAXIMUM PRESSURE IS INDICATED ON THE PRESSURE GAUGE
LOOSENING THE LOCK NUT
SAAB
291-17
Page 286
5. Adjust the tension of the spring by rotating the spring
seating clockwise (inwards) or counter-clockwise (outwards) in accordance with the following table. Ensure
that the valve does not turn as the spring seating is rotated. Thereafter, retighten the lock nut.
I
Charging pressure
Charging pressure reading from test driving
(bar)
1 out
0.82
3/4 out
0.78
1-------------
0.74
Sealing the charge pressure regulator
To avert unauthorised adjustment of the charging pressure, the charge pressure regulator must be sealed. Fit
the seal to the long diaphragm ·bolt which has a hole for
the purpose.
Authorized Saab workshops will be supplied with sealing
pliers and special seals.
Screw the spring seating
in or out the following
number of turns
0.86
1/2 out
~-----------1/4 out
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Cleaning the charge pressure regulator
(In conjunction with inspection)
1. Remove the heat shield.
2. Remove the exhaust line and the diaphragm housing
cover.
3. Dry and clean the diaphragm housing using a brush.
4. Replace the cover, exhaust line and heat shield.
0.70
CORRECT VALUE :
0.66
1/4 in
I
~----------0.62
-----------
.--
1/2 in
0.56
3/4 in
0.54
1 in
SEALING THE CHARGE PRESSURE REGULATOR
Pressureswitch
ADJUSTMENT
1. Counter-clockwise
2. Clockwise
6. Replace the cover and gasket, exhaust line and heat
shield.
7. Test drive the car and check the charging pressure.
8. Seal the charge pressure regulator.
PRESSURE SWITCH
Checking
1., Start the engine and have it idle.
2. Disconnect the hose to the pressure switch at the inlet
291-18
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Page 287
manifold and connect gauge 83 92 813, together with
a suitable pump (e.g. cooling system tester) to the
pres~ure switch hose.
3. Increase the pressure by means of the pump and check
the pressure at which the engine cuts out. Refer to the
specifications in section 0.
Checking
Check the turbo pressure gauge following the same procedure as that for checking of the pressure switch. At
maximum charging pressure, the needle should be within
the wide orange zone.
At the pressure switch actuating pressure, the needle
should be in front of the limit between the orange and
the red zones.
............
Removal and installation
1. Remove the three screws at the bottom of the safety
padding on the instrument panel side of the car.
2. Pull the safety padding away to release the spring clips
(see Service Manual, section 853).
3. Disconnect the hose at the joint below the padding
and disconnect the electric cables.. Undo the nut underneath the safety padding and remove the instrument.
CHECKING THE PRESSURE SWITCH
Changing the pressure switch
To change the pressure switch, remove the rubber r.over
and cables and then unscrew the pressure switch from its
mounting.
Turbo pressuregauge
TURBO PRESSURE GAUGE INSTALLATION
Refit in the reverse order.
To dismantle the instrument, e.g. to replace a bulb, etc.,
remove the screw at the front of the casing.
r
TURBOINSTRUMENT
r
SA.Ml
291-19
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Page 288
Fault diagnosis chart, Saab Turbo
FAULT
CAUSE
REMEDY
Noise or vibration from
the turbo compressor
Poor lubrication of the turbo shaft
bearing
Check the oil pressure and flow to the
turbo. If the fault should persist after
remedial action (permanent bearing
damage) exchange the turbo compressor.
Leakage in the induction or exhaust
system
Tighten leaking connections and replace
defective seals and gaskets
Unbalanced turbo shaft owing to
damage
Exchange the turbo compressor
Leakage between the compressor and
cylinder head or between the cylinder
head and turbine
Tighten leaking connections and replace
defective seals and gaskets
Incorrect setting of charging pressure
Adjust the charge pressure regulator
Valve in charge pressure regulator sticks
in open position
Overhaul the charge pressure regulator
Partially clogged exhaust system
Clean or replace exhaust system
Clogged air cleaner
Change cartridge
Binding turbo shaft
Exchange turbo compressor
Leakage at exhaust pressure line connections
Tighten; if necessary, replace nipples
Clogged exhaust pressure line
Remove and clean
Damaged diaphragm in charge pressure
regulator
Replace diaphragm
Valve in charge pressure regulator sticks
in closed position
Overhaul the charge pressure regulator
Ice formation in exhaust pressure line.
(Excessive pressure occurs 1-2 min
after cold start when ambient temperature below freezing)
Avoid heavy loading of engine immediately after cold starting
Incorrect setting of charging p·ressure
Adjust charge pressure regulator
Insufficient charging
pressure
Excessive charging pressure
291-20
Page 289
FAULT
CAUSE
REMEDY
Metallic noise from charge
pressure regulator
Play in regulator valve
Overhaul the charge pressure regulator
Spring insufficiently
sure regulator
Adjust position of spring (replace as
necessary)
Engine knocking (pinking)
Oil leakage at turbo shaft
seals (oil fumes in exhaust)
offset in charge pres-
Excessive charging pressure
Adjust charging pressure
Unsuitable fuel (octane too low)
Change fuel
Ignition setting too far advanced
Adjust timing
Poor return flow from turbo:
- Clogged return line
-
Excessive crankcase pressure
Turbo unit seals damaged
SAAB
Check return line
Check crankcase ventilation
Exchange turbo compressor
291-21
Page 290
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