Pulse damper

PULSE DAMPER

The pulse damper is connected upstream of the fuel distributor and it serves to suppress the pulsing noises that can occur at low engine rpm. The pulsing is generated by pressure differences of the fuel arising from the opening and closing of the electroinjectors or of the pressure regulator.

1. Fastening pin
2. Diaphragm
3. Spring
4. Covering

REMOVAL/REFITTING

• Disconnect the battery (-) terminal.
• Remove the intake box (see specific paragraph).

1. Slacken the two nuts fastening the pulse damper and fuel pressure regulator support bracket.
2. Disconnect the throttle control shaft return spring.

ELECTROINJECTORS

The electroinjectors are installed on the bodies, immediately upstream of the intake valves. The injector nozzle is formed so that the jet of fuel atomizes into a 30° cone. The injectors are locked by the fuel distributor which presses them into their housings. The injectors are also anchored to the fuel distributor by "safety catches".

1. Injector body
2. Needle
3. Magnetic core
4. Coil spring
5. Winding
6. Injector nose
7. Adjustable spring plate
8. Filter
9. Electrical connector
10. Vacuum seal ring
11. Fuel seal ring

Two O-rings ensure tightness on the intake bodies and on the fuel distributor manifold. The electroinjectors have the task of metering the amount of fuel needed by the engine. They are "all or nothing" devices i.e. they only have two possible conditions, either open or closed. They will let the fuel pass when they are "open" and prevent it from being delivered when they are "closed".

REMOVAL/REFITTING

1. Turn the support bracket just enough to slacken the pulse damper fastening nut.
2. Raise the damper, disconnect the two fuel pipes and remove it.

9 ÷ 12 Nm
1.0 ÷ 1.2 kgm