Repair Manual

17
IGNITION AND INJECTION
17 - 5
1 - The upper part (hydraulic part)
2 - The lower part (body-valve)
3 - Pressure regulator
4 - Injector
5 - Air sensor T
6 - Fuel input ( supply connection ).
7 - Fuel output ( back-feed connection )
8 - Idle motion regulator
A =
Connector for air sensor T aer and
injector.
B = Connector for valve potentiometer.
C = Connector for idle motion breaker and
valve positioning engine.
INJECTION CENTRAL UNIT
PRESSURE REGULATOR
It is a mechanical membrane regulator which insures an injection pressure of 0,8 – 1,15
bar, the engine being under motion.
The pressure is measured as follows:
-a T connection and a manometer of 0 – 4 bar are connected to the fuel input
connection into the valve body;
- the pump is supply by starting the engine or by shunting the terminals 30 and 87
of the relay R1, with both engine and contact OFF.
AIR TEMPERATURE SENSOR ( AIR T )
The air T sensor (5) – (drawing 4) measures the temperature of the air sucked by the
engine.
Knowing that the air density decreases with the temperature increasing, the electronic
control unit will correct the injection time (t
i
), in order to maintain the report air/fuel at
optimal values.
The air sensor T is a NTC type (temperature negative coefficient), which means that
its internal resistance decreases with temperature increase. It is supplied with U = 5 V
(pin 13, computer).
Reference values: R = 1450 – 3300 Ù at 15 – 30 °C
R = 2500 ± 125 Ù at 20 °C
The injection central unit consists of:
Fig. 2
DESCRIPTION OF THE SYSTEM
vnx.su