Saab 1987 900 - Page 46

44 Technical description
B Electronic injection system (LH), 16 valve engines
20
19
d:::==:::::I.
S G483
1. Fuel tank
11. Inlet manifold
2. Fu el pumps
3. Fuel filter
12. Throttle switch
13. Idle speed actuator (AIC)
4. Fuel pipe
14. Airmass meter w/hot wire
5. Pressure regulator
6. Electronic control unit
15. Heated oxygen sensor
16. Overpressure switch (Turbo only)
7. Ignition distributor
8. Temp. transmitter (NTC)
17. Relay system
18. Fuel pump relay
9. Inj ec tion valv es (4)
10. Vacuum hose
19. Battery
20. Ignition switch
C. Decel dashpot (automatic transmis-
sion, 8 valve/all 16 valve)
The decel da sh pot acts upon the throttle
mechanism to minimize incompl ete com-
bustion during engine deceleration.
D. Decel fuel shutoff (manual trans-
mission only, 8 valve)
A solenoid op erated air by-pass valve redu-
ces air flow in the air flow sensor, lowering
the fuel distributor plunger interrupting
fuel flow during deceleration. The solenoid
is controlled
by an engine speed relay and a
throttle contact switch. During decelera-
tion at engine speeds above 1575 RPM the
solenoid opens the by-pass valve. When the
speed drops below 1375 RPM the system de-
activates
allowing normal operation.
E. Lambda control system (8 valve)
The Lambda contro l system is a closed loop
feedback system
adapted to the C.l. System
to constantly
maintain close air/fuel ratio
control under all operating conditions. At
an air/fuel ratio of14.5 to one (Lambda = 1
at this rati o), all three regulated pollu tant s
(unburned h ydrocarbons, carbon monox-
ide, oxides
of nitrogen) may be simulta neo-
usly controll
ed efficiently by a special thre-
eway catalyst.
An oxygen sensor in the