Alfa Romeo 33 Workshop Manual Supplement Vol. 2

By: Factory .

This book is a workshop manual supplement for Alfa Romeo models 33. This publication covers Engine with electronic injection LE3-Jetronic, Fuel supply system, Electronic-Injection engine 16 Valve.

Description For electronic injection 1.7 engines

GENERAL DESCRIPTION

The JETRONIC LE 3.2 electronic system consists an inductive discharge transistorized injection system equipped with a control unit (CU). The ignition, however is ensured by an electronic ignition system equipped with an electronic power module. The data necessary for controlling the system is collected by means of sensors that transform the data into electrical signals. This data concerns:

• battery voltage
• position of the accelerator throttle (completely closed or open)
• air intake temperature
• engine coolant temperature
• quantity of air taken in by the engine
• quantity of oxygen present in the exhaust gases
• engine r.p.m. (from the distributor)

The electronic CU calculates the opening time of the electroinjectors with relation to the instantaneous r.p.m. and load condition of the engine.

Having carried out the calculation. the CU sees to the opening of the electroinjectors for this time. Since the difference between fuel pressure and air pressure in the manifold is mantained constant by a regolator, the quantity of fuel injected is proportional to the delivery time. Furthemore the injection CU is able to carry out from time to time certain operations considered necessary under certain engine conditions (e.g. electroinjector for cold start, interruption of fuel delivery when engine is decelerating). The Injection CU also controls the delivery of the fuel pump.

JETRONIC LE 3.2 INJECTION SYSTEM

The system, which consists of an air system and of a fuel system includes the following:

• A filter-equipped fuel pump
• a pulsation damper whose task is to eliminate pulsations due to pressure peaks
• a pressure gauge which keeps constant pressure difference between fuel system and intake manifold
• four electroinjectors which, owing to pressure gauge, supply a fuel quantity dependent on their opening time an air flow sensor, which measures ait taken in by engine (adjusted in relation to air temperature) supplementary air solenoid valve suppliyng extra air when the engine is cold
• a switch on accelerator throttle recognizing the two cases of open or closed throttle
• an engine coolant temperature sensor for injection CU
• an rpm sensor
• pipes and electrical wiring, including remote control switches and CU (inserted in air flow sensor)
• a lambda probe determining oxygen differences, in exhaust gas, with respect to the air (only for models with catalytic converter).

IGNITION SYSTEM

This system consists of:

• an electronic power module
• a high voltage shock generating coil
• a high voltage distributor supplying power to spark plugs
• four ignition spark plugs
• electrical wiring at low and high voltage

Other Details