Coolant Temperature Sensor; Idle Adjustment Pass - Alfa Romeo 33 Workshop Manual

greater resistances, due to friction,
air solenoid valve
A I R FLOW~
U N I T
nishing the e(ectronic'CU with an elec-
ter, with re'lation: to the air flow taken
The sensitive element is a floating
throttle which opens according to the
amount of air taken in (a function of
the engin+ r.~p.m. and the opening of
A compensating throttle coupled to
the floating throttle compensates for
FUEL SYStEM
1 Air flow sensor
C O O L A N T
T E M P E R A T U R E SENSOR ~~ ~ ~
When starting the engine from cold,
the engine requires a considerably en-
be reduced as themtemperature of the
engine increases and eliminated when
the engine reaches normal running' i ,,
temperature.
These variations in temperature :are
transmitted to electronic CU by the,
CU then control the quantity of fuel in-
jected.
Engine coolant temperature sensor
1
SWITCH ON BODY
OF ACCELERATOR THROT-
TLE
The switch on the throttle body is firm- ,.
ly fixed to the spindle of the accelera-
tor throttle valve. The switch contains
a full load contact. In this way a
is sent to the electronic CU when the
air-petrol ratio according to the requi-
rements of th,ese engine conditions.
When the aceelerator is released the
fuel supply is tut off by means of the
minimum throttle opening switch.
When the accelerator throttle valve
closes and the engine r.p.m. (s higher
than 1600 r.p.m., the fuel'supply is tut
off until the engine r.p.m. cornes down
supply is restored. The main purpose
of fuel tut-off when the accelerator is
released is to reduce both fuel con-
sumption and the emission of unburnt
hydrocarbons which usually form du-
ring this phase.
A tube connecting the corrugated air
intake sleeve#with the supply manifold
throttle; the 'amount of air that cari
pass through, this tube cari be varied
by means ofI an adjusting screw. By
acting on this adjusting screw the'jdle
thout affectrng.the exhaust CC%.
air taken in by the engine whsn this
screw is adjusted is measured by the
air flow sensor which in turn provides
for the proportional correction of the
quantity of fuel that is injecfed.
1 lLo6k n u t
2 ~ r ldle r.p.m: adjusting screw
P A 3 2 7 9 0 0 8 8 3 3 0 1