Toyota Cressida/Corona/Crown/MarkII 1970-1982 Repair Guide

Description of System


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Fig. Fig. 1 Exploded view of the fuel injection system components-1981-82 Cressida

The 4M-E and 5M-E engines are equipped with electronic fuel injection. The EFI system precisely controls fuel injection to match engine requirements, reducing emissions and increasing driveability.

The electric fuel pump pumps fuel through a damper and filter to the pressure regulator. The six fuel injectors are electric solenoid valves which open and close by signals from the control unit.

The EFI computer receives input from various sensors to determine engine operating condition.

Air flow meter-measures the amount of intake air.
Ignition coil-engine RPM.
Throttle valve switch-amount of throttle opening.
Water temperature sensor or cylinder head temperature sensor-temperature of coolant or engine.
Air temperature sensor-temperature of intake air (ambient temperature).
Thermotime switch-signal used to control cold start valve fuel enrichment when the engine is cold.
Starting switch-signals that the starter is operating.
Altitude switch used to signal changes in atmospheric pressure.
Exhaust gas sensor used to measure the oxygen content of the exhaust gas. The sensors provide the input to the control unit, which determines the amount of fuel to be injected by its preset program.

The fuel injection system is a highly complex unit. All repair or adjustment should be left to an expert Toyota technician.