Page 51
88
LH fuel system 2.4: 116 Lambda, 1988, US, CA, JP, SE, EU, AU
103
136
152A
152B
156
159
176
200
201
202
203
204
205
206
24%
229
272
272
285
Fuel pump 324
in the fuel tank, under the luggage compart-
ment floor
Lambda sensor
on the exhaust manifold 322
29-pole white connector
29-pole red connector
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing.
The connectors are accessible from the inte-
rior of the car
Relay for the AC compressor
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing
Distribution terminal +15
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
Control unit for EZK ignition system
in the engine compartment, forward of the
left-hand wheel housing
Control unit for the LH system
forward of the right-hand front door, below
the facia (behind the trim)
Engine earthing point
at the engine lifting lug
Engine temperature transmitter
on the intake manifold flange, between cyl-
inders 2 and 3
Throttle angle transmitter
on the engine throttle housing
Test connector
in the engine compartment, behind the
right-hand wheel housing
Air mass meter
on the air hose at the air cleaner
Fuel injection valves
on the engine intake manifold
Earthing point on the gearbox
Main relay for the fuel injection system
forward of the right-hand front door, below
the facia (behind the trim)
Preheater
in the Lambda sensor, on the exhaust mani-
fold
Idling speed adjustment motor
at the extreme front, on the left-hand side of
the cylinder head
Fuse for Lambda sensor
in the engine compartment, on the right-
hand side, at the air intake
Valve for charcoal cannister
in the engine compartment, forward of the
left-hand wheel housing, between the
wheel housing member and the outer wing
Connector, Auto/Man, LH 2.4
at the control unit, forward of the right-hand
front door, below the facia (under the trim)
Saab 900
Page 52
LH fuel system 2.4: 116 Lambda, 1988, US, CA, JP, SE, EU, AU ee ie
Components 59
| of the
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321 159
7 101,103
204
136
271
Page 53
90
Ignition system with tachometer and timing service instrument socket — 1987
ignition system with tachometer and timing
service instrument socket — 1987
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Page 54
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Ignition system with tachometer and timing service instrument socket 1987 91
Operation
This breakerless ignition system is equipped with a
Hall sensor. (The EZK ignition system is discussed in
a separate section.)
When ignition switch 20 is in the start or drive posi-
tion, ignition coil 5, amplifier 146 and ignition pulse
amplifier 147 will be energised (+15).
The amplifier receives ignition pulses via a 3-core
shielded cable from the Hall sensor in ignition dis-
tributor 6. The frequency of the pulses is proportional
to the engine speed.
The pulses are amplified and adjusted in amplifier
146. A high-tension pulse is generated in the sec-
ondary winding each time a pulse breaks the primary
circuit of the ignition coil. The high-tension pulse is
then supplied to the corresponding spark plug viathe
distributor.
Tachometer 110 is supplied across fuse 7. The con-
trol pulses required for displaying the engine speed
are supplied from the ignition pulse amplifier.
Timing service instrument (TSI) socket 73 is intended
for a special ignition service instrument and has the
following terminals:
1. Positive supply direct from battery 1
2. Earth
3. Solenoid (terminal 50) on starter motor 4
4
Positive supply (+15) from the ignition switch
when the latter is in the start or drive position
5. Ignition pulses from ignition pulse amplifier
147
6. Not used
Fora more detailed description of each component in
the ignition system, see the Service Manual, 3:1,
Electrical system, Instruments.
Fault-tracing hints
The ignition system will be energised when the igni-
tion switch is in the drive position.
1. Check that terminal 15 on the ignition coil and
terminal 4 on the timing service instrument
socket are live.
Check that terminal 4 on amplifier 146 is live.
Check that ignition pulse amplifier 147 is ener-
gised (terminal 15) and that the amplifier out-
put delivers ignition pulses (measure at the TSI
socket).
4. Tachometer: Check fuse 7 first and check that
the supply to it is live. Check that terminal 3 on
the circuit board for tachometer 110 is live, and
that ignition pulses are being supplied from the
ignition pulse amplifier.
5. Check all connectors, cable harnesses and
earth connections.
See also the fault-tracing section for each compo-
nent in the Service Manual, Group 3:1, Electrical
system, Instruments.
Locations of components
The location of the components are the same for the
1987 and 1988 models, Ignition system — 1988 (see
pages 94-95).
Saab 900
Page 55
a
92 Ignition system with tachometer and timing service instrument socket — 1988 |
Ignition system with tachometer and timing |
service instrument socket — 1988
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Page 56
Ignition system with tachometer and timing service instrument socket — 1988 93
Operation
This breakerless ignition system is equipped with a
Hall sensor. (The EZK ignition system is discussed in
a separate section.)
When ignition switch 20 is in the start or drive posi-
tion, ignition coil 5 and amplifier 146 will be ener-
gised (+15).
The amplifier receives ignition pulses via a 3-core
shielded cable from the Hall sensor in ignition dis-
tributor 6. The frequency of the pulses is proportional
to the engine speed.
The pulses are amplified and adjusted in amplifier
146. A high-tension pulse is generated in the sec-
ondary winding each time a pulse breaks the primary
circuit of the ignition coil. The high-tension pulse is
then supplied to the corresponding spark plug via the
distributor.
Tachometer 110 is supplied across fuse 7. The con-
trol pulses required for displaying the engine speed
are supplied from the amplifier.
Timing service instrument (TSI) socket 73 is intended
for a special ignition service instrument and has the
following terminals:
1. Positive supply direct from battery 1
2. Earth
3. Solenoid (terminal 50) on starter motor 4
4
Positive supply (+15) from the ignition switch
when the latter is in the start or drive position
5. Ignition pulses from ignition system amplifier
146
6. Not used
For a more detailed description of each component in
the ignition system, see the Service Manual, 3:1,
Electrical system, Instruments.
Fault-tracing hints
The ignition system will be energised when the igni-
tion switch is in the drive position.
1. Check that fuse 3, terminal 15 on the ignition
coil and terminal 4 on the timing service in-
strument socket are live.
2. Check that terminal 4 on amplifier 146 is live.
3. Tachometer: Check fuse 7 first and check that
the supply to it is live. Check that terminal 3 on
the circuit board for tachometer 110 is live, and
that ignition pulses are being supplied from the
amplifier.
4. Check all connectors, cable harnesses and
earth connections.
See also the fault-tracing section for each compo-
nent in the Service Manual, Group 3:41, Electrical
system, Instruments.
Saab 900
Page 57
94
Ignition system with tachometer and timing service instrument socket — 1988
Locations of components
The locations of the components listed below are the
same for the 1987 and 1988 models.
1
20
22A
60
13
(9
93
102
110
146
147
Battery
on the right-hand side of the engine com-
partment
Earthing point in the facia
Starter motor
on the left-hand side of the engine (intake
side)
Ignition coil
on the cross-member above the radiator
Ignition distributor
. at the front of the engine
Earthing point, radiator cross-member
Ignition switch
on the centre console between the front
seats
Fuse holder
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
Single-pole connector
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
Timing service instrument socket
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
Distribution block
in the engine compartment, on the right-
hand side
Earthing point, left-hand wheel housing
member
Fuel pump relay
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing
Tachometer
in combined instrument 47 on the facia
Amplifier for the electronic ignition system
inthe engine compartment, on the left-hand
wheel housing
Ignition pulse amplifier
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing
152A
152B
tov
158
hse,
244
29-pole white connector
29-pole red connector
in the engine compartment, in the electrical
distribution box on the left-hand wheel
housing. The connectors are accessible
from the interior of the car.
Spark plug
on the engine
Negative distribution terminal
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing
Distribution terminal +15
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
Earthing point on the gearbox
Saab 900
Page 58
Ignition system with tachometer and timing service instrument socket— 1988 95
Components
lectrical
1 wheel
cessible
the en-
1 wheel
the en-
1 wheel
147 (M1987)
152A
152B
158
159 (M1987)
102 110 (47) 146 147
Page 59
96 = EZK ignition system with tachometer and timing service instrument socket — 1987
EZK ignition system with tachometer and timing
service instrument socket — 1987
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Saab 900
Page 60
987
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75
EZK ignition system with tachometer and timing service instrument socket— 1987 97
Operation
The EZK ignition system is fitted only to 16-valve
engines without turbocharger. This breakerless igni-
tion system is equipped with a Hall sensor. It is
controlled by a knock sensor, which provides the
highest possible engine performance on any grade of
fuel. This provides good fuel economy and cleaner
exhaust gases.
When ignition switch 20 is in the start or drive posi-
tion, ignition coil 5, amplifier 146 and EZK control
unit 176 will be energised (+15).
Control unit 176 receives ignition pulses via a
three-core shielded cable from the Hall sensor in
ignition distributor 6. The frequency of the pulses is
proportional to the engine speed. The control unit
then adjusts the timing in accordance with the follow-
ing factors:
®@ engine speed
@ engine load
@ any knocking tendencies
The pulses supplied from terminal 16 of the control
unit are amplified and adjusted in amplifier 146. A
high-tension pulse is generated in the secondary
winding each time a pulse breaks the primary circuit
of the ignition coil. The high-tension pulse is then
supplied to the corresponding spark plug (157) via
distributor 6.
The ignition is set at 5° when the engine is started.
This ignition setting is dependent on the speed of the
engine, and adjustment starts at around 700 rpm. It
is adjusted in accordance with the values stored in
the control unit. (The distributor has no centrifugal or
vacuum advance mechanisms.)
Fuel system control unit 200 provides the ignition
system with information on the engine load. Throttle
angle transmitter 203 is connected (earthed) when
the throttle is closed, i.e. when the engine is idling.
When the load has exceeded the value stored in the
control unit, the timing will be retarded by around 6°
on all cylinders. The timing returns to normal in steps
of around 1° after the load has ceased to increase.
The control unit receives information on knocking in
any of the cylinders via knock sensor 178. The timing
is then retarded on the knocking cylinder only, in
steps of around 3°. This will continue until the knock-
ing ceases, or until the timing has been retarded by a
total of around 13°. The timing returns to normal in
steps of 0.35°.
EZK test connector 145 is intended for special test
equipment. Terminal 15 of the control unit delivers a
pulse for each knock detected. (Positive voltage is
supplied to the connector when the ignition switch is
in the drive position.)
Should a fault occur in the control unit, a signal
(earth) will be delivered from terminal 3, which will
cause CHECK ENGINE warning lamp 47P to flash.
(This lamp can also be activated by the fuel injection
system.)
Ignition pulse amplifier 147 has been introduced to
provide more accurate control of the systems which
are dependent on ignition pulses, such as the fuel
system.
Ignition pulses are supplied from terminal 16 of the
control unit to the TD-J input of ignition pulse ampli-
fier 147. A "pure” 12 V square-wave pulse is then
supplied from the TD-O output of the amplifier to
timing service instrument socket 73, tachometer
110 and other systems that are dependent on igni-
tion pulses.
Tachometer
Tachometer 110, located in combined instrument
47, is supplied across fuse 7 and 29-pole red con-
nector 152B. The control pulses required for display-
ing the engine speed are supplied from ignition pulse
amplifier 147.
Timing service instrument socket
Timing service instrument (TSI) socket 73 is intended
for a special ignition service instrument and has the
following terminals:
1. Positive supply direct from battery 1
2. Earth
3. Solenoid (terminal 50) of starter motor 4
4
Positive supply from the ignition switch when
the latter is in the start or drive position
5. Ignition pulses from ignition pulse amplifier
147
6. Notused
For a more detailed description of each component in
the ignition system, see the Service Manual, 3:1,
Electrical system, Instruments.
Saab 900