Page 31
Earth connections 41
Ja
s
oS
L.
MAN: US) 4
Components connected 203
Earthing points 201 (two) are located on the engine
cylinder head at the lifting lug. The following compo- -—- 205
nents are connected to this earthing point. Some of
the components are only fitted to cars of certain 261
versions or for certain markets. aes
Cars with 8-valve engine 320
95
96
99
135
4 142
173
203
9 212
271
Auxiliary air valve (EU, ME, FE)
Control pressure valve
Temperature switch Il, Lambda
Lambda control unit
Solenoid valve for raising the idling speed,
AC
Diode for the AC compressor
Throttle angle transmitter for the Cl fuel in-
jection system, Lambda
Solenoid valve for raising the idling speed,
auto. transm.
Preheater for the Lambda sensor (I8
Lambda)
Cars with 16-valve engine
95
130
142
173
176
200
202
Auxiliary air valve (EU, ME, FE)
Radiator coolant temperature warning
switch (ME, FE)
Solenoid valve for raising the idling speed,
AC (EU, ME, FE)
Diode for the AC compressor
Control unit for EZK ignition system (across
3-pole connector 57 in the engine compart-
ment, on the right-hand side at the air in-
take)
Control unit for the LH fuel injection system
Engine temperature transmitter for the LH
fuel injection system
Throttle angle transmitter for the LH fuel
injection system
Air mass meter for the LH fuel injection sys-
tem
Throttle contacts, zero position, shift-up in-
dication
Preheater for the Lambda sensor
Ignition coil with integrated amplifier
Saab 900
Page 32
42 Starting system
Starting system
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Saab 900
Page 33
UT
Starting system 43
Operation
The supply to ignition switch 20 is taken from battery
1 across 29-pole white connector 152A, and a supply
cable is also run directly from the battery to terminal
30 of starter motor 4.
When the ignition switch is turned to the start posi-
tion, the solenoid coil in the starter motor will be
energised (+50). The coil will close the starting con-
tacts, so that current will flow from the battery
through the starter motor, and the starter motor will
start to rotate.
Automatic tranmission
Cars with automatic transmission are also equipped
with a start inhibitor switch which prevents the en-
gine from being started when one of the gears is
engaged.
Fault-tracing hints
4. Check that terminal 30 of starter motor 4 is live.
2. Check the energising voltage to the starter mo-
tor solenoid when the ignition switch is in the
start position.
3. Check start inhibitor switch 77 on cars with au-
tomatic transmission.
4. Check that the engine is earthed to the chassis
of the car.
5. Check the connectors and the wiring.
Saab 900
Page 34
44 Starting system
Locations of components
1 Battery
on the right-hand side of the engine com-
partment
4 Starter motor
on the left-hand side of the engine (intake
side)
7 Earthing point, radiator cross-member
20 Ignition switch
on the centre console between the front
seats
60 Single-pole connector (only on cars with au-
tomatic transmission)
under the centre console, between the front
seats )
75 Distribution block
in the engine compartment, on the right-
hand side
CE Start inhibitor switch (only on cars with auto-
. matic transmission) )
at the selector lever
152A 29-pole white connector
in the engine compartment, in the electrical
distribution box on the left-hand wheel
housing. The connector is accessible from
the interior of the car.
20 Earthing point on the gearbox
Saab 900
Page 35
ee —
ts
le engine com-
engine (intake
-member
2en the front
| Cars with au-
en the front
in the right-
'S with auto-
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and whee|
isible from
Starting system
45
Components
75
Saab 900
Page 36
64
Cl fuel system: I8 Lambda, 1987 model, US, CA, JP, AU
Cl fuel system: I8 Lambda, 1987 model, US
CA, JP, AU
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Saab 900
Page 37
IS,
pee eS Se Ne
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=
Cl fuel system: 18 Lambda, 1987 model, US, CA, JP, AU 65
Operation
The Cl (Continuous Injection) fuel system with emis-
sion control (Lambda) is of mechanical type and is
used for 8-valve engines. It consists basically of the
conventional Saab Cl system, although it is supple-
mented with equipment for more accurate adjust-
ment of the fuel/air mixture.
The Cl system
When the ignition key is turned to the start position,
power will be supplied (+50) to starter motor 4 and
temperature time switch 92.
If the engine is cold, i.e. if its temperature is below
+45 °C, temperature time switch 92 will be closed.
Starting valve 94, which is energised from terminal
15a of starter motor 4, will then be earthed. The valve
will thus be open, and the engine will be supplied
with additional fuel during the period when the start-
er motor is energised (although no longer than about
9 seconds). ‘
If the ignition switch is in the start or drive position,
fuel pump relay 102 will be energised (+15) across
fuse 22. Relay 102 will be energised and fuel pumps
103 and 101, which are supplied across fuse 30, will
Start to run. At the same time, the heating coils in
auxiliary air valve 95 and control pressure valve 96
will also be energised.
Ignition pulses will be supplied from ignition pulse
amplifier 147 to the fuel pump relay and the Lambda
system. If the engine should stop, the pulses will
cease and the relay will then trip, thus interrupting
the supply to the fuel system components.
Lambda
The Lambda equipment includes a Lambda sensor
136 which continuously supplies information to con-
trol unit 135 on the oxygen content in the exhaust
gases. On the basis of this information, and the
signals received by the control unit from the various
sensors and relays of the Lambda system, the control
unit adjusts the quantity of fuel injected through
timing valve 139. (The valve is controlled by earthing
of terminal 15.)
Control unit 135 and the relays in relay box 108 are
supplied across the contacts in relay 102, from ter-
minal 87. Time-delay relay 106 and hot start relay
104 are used during the starting stage. The relays
are energised (+50) when ignition switch 20 is in the
Start position. The time-delay relay actuates the con-
trol unit and timing valve 139 to increase the fuel
supply to the engine. The hot start relay pulses start-
ing valve 94 even if the engine is hot on starting (i.e.
if temperature time switch 92 would not normally
open the valve).
Temperature switch 97 senses the engine tempera-
ture. It opens at a temperature above +45 °C and
closes at +38 °C. Switch 97 is connected in series
with temperature time switch 92.
Vacuum switch 79 is used for controlling the fuel
enrichment during acceleration. If the engine is cold,
the switch will open starting valve 94. If the engine is
hot, a signal is applied instead to time-delay relay
106 which actuates the control unit to increase the
fuel supply (active up to 2 minutes after starting).
Engine speed relay 105 is used together with sole-
noid valve 260 and throttle angle transmitter 203 for
shutting off the fuel on overrun braking. The trans-
mitter closes the earth circuit to relay 105 when the
accelerator pedal is released. This function is also
operative when the engine speed is in excess of
about 1375 r/min. The relay is fitted only to cars with
manual gearbox.
Throttle angle transmitter 203 is closed via pins 1
and 2 only when the throttle is in the idling position
(throttle angle of 0°), and is closed via pins 2 and 3
when the throttle angle is between 72° and 90°.
Temperature switch 99 opens at +25 °C and closes
at +19 °C. One of its functions is to improve the fuel
enrichment.
Connector 120 is intended for a special instrument
and is used for adjusting the timing ratio. The con-
nector is energised when the ignition switch is in the
drive position.
Fit the solenoid valve for raising the idling speed
(212) if necessary (applies to cars with automatic
transmission for the USA market). The cars have been
pre-wired for this.
Fault-tracing hints
For particulars of fault-tracing in the fuel system with
the Lambda system, see the Service Manual, Group
2:3, Fuel system, fuel injection.
The system includes several components that de-
mand special care during fault-tracing and replace-
ment. So read all of the instructions in the Service
Manual before carrying out fault-tracing work on the
components and in the wiring.
Locations of components
The locations of the components are the same for the
1987 and 1988 models of I8 Lambda engines with
Cl, for US, CA, JP and AU (see pages 68-69).
Saab 900
Page 38
66 Cli fuel system: I8 Lambda, 1988 model, US, CA, JP, AU
Cl fuel system: I8 Lambda, 1988 model, US,
CA, JP, AU
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Saab 900
Page 39
Cl fuel system: 18 Lambda, 1988 model, US, CA, JR AU 67
Operation
The Cl (Continuous Injection) fuel system with emis-
sion control (Lambda) is of mechanical type and is
used for 8-valve engines. It consists basically of the
conventional Saab Cl system, although it is supple-
mented with equipment for more accurate adjust-
ment of the fuel/air mixture.
The Cl system
When the ignition key is turned to the start position,
power will be supplied (+50) to starter motor 4 and
temperature time switch 92.
lf the engine is cold, i.e. if its temperature is below
+45 °C, temperature time switch 92 will be closed.
Starting valve 94, which is energised from terminal
15a of starter motor 4, will then be earthed. The valve
will thus be open, and the engine will be supplied
with additional fuel during the period when the start-
er motor is energised (although no longer than about
9 seconds).
If the ignition switgh is in the start or drive position,
fuel pump relay 102 will be energised (+15) across
fuse 22. Relay 102 will be energised and fuel pumps
103 and 101, which are supplied across fuse 30, will
start to run. At the same time, the heating coils in
auxiliary air valve 95 and control pressure valve 96
will also be energised.
Ignition pulses will be supplied from ignition system
amplifier 146 to the fuel pump relay and the Lambda
system. If the engine should stop, the pulses will
cease and the relay will then trip, thus interrupting
the supply to the fuel system components.
Lambda
The Lambda equipment includes a Lambda sensor
136 which continuously supplies information to con-
trol unit 135 on the oxygen content in the exhaust
gases. On the basis of this information, and the
signals received by the control unit from the various
sensors and relays of the Lambda system, the control
unit adjusts the quantity of fuel injected through
timing valve 139. (The valve is controlled by earthing
of terminal 15.) The Lambda sensor is heated by
preheater 271 (protected by fuse 285 in the wiring).
Control unit 135 and the relays in relay box 108 are
supplied across the contacts in relay 102, from ter-
minal 87.
Time-delay relay 106 and hot start relay 104 are
used during the starting stage. The relays are ener-
gised (+50) when ignition switch 20 is in the start
position. The time-delay relay actuates the control
unit and timing valve 139 to increase the fuel supply
to the engine. The hot start relay pulses starting valve
94 even if the engine is hot on starting (i.e. if tem-
perature time switch 92 would not normally open the
valve).
Temperature switch 97 senses the engine tempera-
ture. It opens at a temperature above +45 °C and
closes at +38 °C. Switch 97 is connected in series
with temperature time switch 92.
Vacuum switch 79 is used for controlling the fuel
enrichment during acceleration. If the engine is cold,
the switch will open starting valve 94. If the engine is
hot, a signal is applied instead to time-delay relay
106 which actuates the control unit to increase the
fuel supply (active up to 2 minutes after starting).
Diode 339 prevents the supply from reaching relays
104:50 and 106:50 when switch 79 is closed.
Engine speed relay 105 is used together with sole-
noid valve 260 and throttle angle transmitter 203 for
shutting off the fuel on overrun braking. The trans-
mitter closes the earth circuit to relay 105 when the
accelerator pedal is released. This function is also
operative when the engine speed is in excess of
about 1375 r/min. The relay is fitted only to cars with
manual gearbox.
Throttle angle transmitter 203 is closed via pins 1
and 2 only when the throttle is in the idling position
(throttle angle of 0°), and is closed via pins 2 and 3
when the throttle angle is between 72° and 90°.
Temperature switch 99 opens at +25 °C and closes
at +19 °C. One of its functions is to improve the fuel
enrichment.
Connector 120 is intended for a special instrument
and is used for adjusting the timing ratio. The con-
nector is energised when the ignition switch is in the
drive position.
Fit the solenoid valve for raising the idling speed
(212) if necessary (applies to cars for the USA market
with automatic transmission). The cars have been
pre-wired for this.
Fault-tracing hints
For particulars of fault-tracing in the fuel system with
the Lambda system, see the Service Manual, Group
2:3, Fuel system, fuel injection.
The system includes several components that de-
mand special care during fault-tracing and replace-
ment. So read all of the instructions in the Service
Manual before carrying out fault-tracing work on the
components and in the wiring.
Saab 900
Page 40
68 Cl fuel system: I8 Lambda, 1988 model, US, CA, JP, AU
Locations of components
The locations of the components presented below are the
same for the Cl fuel systems on 1987 and 1988 models
with 18 Lambda engines for US, CA, JP and AU.
4 Starter motor
on the left-hand side of the engine (intake side)
Earthing point on the radiator cross-member
9 Earthing point in the luggage compartment
20 Ignition switch
on the centre console between the front seats
22A Fuse holder
in the electrical distribution box in the engine
compartment, on the left-hand wheel housing
cH Reversing light switch
under the centre console, at the selector lever
59 2-pole connector
one in the electrical distribution box in the en-
gine compartment, on the left-hand wheel hous-
ing
two in the luggage compartment, adjacent to the
fuer pumps
one connector 120 in the engine compartment,
at the left-hand wheel housing
one for the Lambda sensor, under distribution
block 75, on the right-hand side of the engine
compartment
60 Single-pole connector
one in the electrical distribution box in the en-
gine compartment, on the left-hand wheel hous-
ing
One in the engine compartment, on the right-
hand side, beside the air intake
two under the centre console, at the selector
lever (auto.)
76 Switch for raising the idling speed (auto.)
under the centre console, at the selector lever
UC Start inhibitor switch (auto.)
under the centre console, at the selector lever
79 Vacuum switch
in the engine compartment, on the inside of the
left-hand wheel housing member, at the fuel fil-
ter
92 Temperature time switch
on the engine thermostat housing
94 Starting valve
on top of the engine throttle housing
95 Auxiliary air valve
at the front of the engine, beside the thermostat
housing
96 Control pressure valve
at the front of the engine, on the thermostat
housing
97 Temperature switch |, Lambda
on the engine thermostat housing
98 10-pole connector
to the left of the steering column, under the facia
(behind the knee shield)
99 Temperature switch Il, Lambda
on the engine intake manifold
101
102
103
104
105
106
108
135
136
139
146
147
152A
152C
156
158
159
201
203
212
260
Zia
285
339
Fuel feed pump
in the fuel tank, under the luggage compartment
floor
Fuel pump relay
in the electrical distribution box in the engine
compartment, on the left-hand wheel housing
Fuel pump
in the fuel tank, under the luggage compartment
floor
Hot start relay
Engine speed relay
Time-delay relay (manual)
in the engine compartment, in the Lambda relay
box, on the left-hand wheel housing
Lambda relay box
in the engine compartment, forward of the left-
hand wheel housing
Lambda control unit
under the back seat, on the right-hand side
Lambda sensor
on the exhaust manifold
Timing valve, Lambda
in the engine compartment, on the inside of the
left-hand wheel housing member
Amplifier for the electronic ignition system
in the engine compartment, on the left-hand
wheel housing
Ignition pulse amplifier
in the electrical distribution box in the engine
compartment, on the left-hand wheel housing
29-pole white connector
29-pole black connector
in the electrical distribution box in the engine
compartment
Relay for the AC compressor
in the electrical distribution box in the engine
compartment, on the left-hand wheel housing
Negative distribution terminal
Distribution terminal +15
in the electrical distribution box in the engine
compartment, on the left-hand wheel housing
‘Earthing point on the engine
Throttle angle transmitter
on the engine throttle housing
Solenoid valve for raising the idling speed (auto.)
at the engine throttle housing, in the hose for the
auxiliary air valve
Fuel shut-off solenoid valve (manual)
on the rubber branch piece above the engine air
cleaner
Preheater for the Lambda sensor
in the Lambda Sensor, on the exhaust manifold
Fuse for the Lambda sensor
on the right-hand side of the engine compart-
ment, at the air intake
Diode
in the Lambda relay box in the engine compart-
ment, forward of the left-hand wheel housing
Saab 900