Mazda 1984 RX7 Specifications download pdf (Page 42)

FUEL INJECTION SYSTEM

Article Text

1984 Mazda RX7

For iluvmyrx7.com

Saturday, June 08, 2002 10:47PM

ARTICLE BEGINNING

1984-85 Fuel Injection

MAZDA

RX7

DESCRIPTION

The electronically controlled fuel injection system precisely

meters the amount of fuel injected in each rotor. The Electronic

Control Unit (ECU) is the "brain" of the system.

The fuel delivery system consists of a fuel tank, filter,

pump, injectors, pressure regulator and pulsation damper. The air

delivery system consists of an airflow meter, air funnel, throttle

chamber, dynamic chamber and intake manifold.

OPERATION

The ECU uses input information to determine fuel output from

the following sensors and devices: airflow meter, throttle sensor,

intake air temperature sensor, atmospheric pressure sensor, engine RPM

(ignition pulse), coolant temperature, oxygen sensor and intake

manifold vacuum sensor.

After receiving the input information, the ECU will determine

the correct fuel pressure at the injectors by sending a signal to the

pressure regulator control solenoid valve. The ECU will also control

the fuel delivery volume by timing the duration of injector "ON" time.

Fig. 1: Testing Fuel Pump Output Pressure

FUEL PUMP PRESSURE TEST

1) Disconnect negative battery terminal. Using a shop rag

wrapped around main fuel hose, disconnect main fuel hose from fuel

line. Connect a pressure gauge to line and reconnect negative battery

terminal.

2) Turn ignition on and jumper across 2 terminals of fuel

pump test circuit connector. See Fig. 1. Fuel pump pressure should be

50-71 psi (3.5-5.0 kg/cm

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Mazda 1984 RX7 Specifications Page 42