EG0FS–01
The SFI system is composed of three basic sub–systems: Fuel, Air Induction and Electronic Control Sys-
tems.
FUEL SYSTEM
EG0FT–01
Fuel is supplied under constant pressure to the SFI injectors by an electric fuel pump. The injectors inject
a metered quantity of fuel into the intake manifold in accordance with signals from the ECM.
AIR INDUCTION SYSTEM
EG0FU–01
The air induction system provides sufficient air for engine operation.
ELECTRONIC CONTROL SYSTEM
EG0FV–01
The CAMRY 3VZ–FE engine is equipped with a TOYOTA Computer Controlled System (TCCS) which cen-
trally controls the SFI, EI, IAC, Diagnosis systems etc. by means of an ECM (ECM–formerly SFI computer)
employing a microcomputer.
By means of the ECM, the controls the following functions:
1. Sequential Multiport Fuel Injection (SFI)
The ECM receives signals from various sensors indicating changing engine operation conditions such as:
Intake air volume
Intake air temperature
Engine coolant temperature
Engine rpm
Acceleration/deceleration
Exhaust oxygen content etc.
The signals are utilized by the ECM to determine the injection duration necessary for an optimum air–fuel
ratio.
2. Electronic Ignition (EI)
The ECM is programmed with data for optimum ignition timing under any and all operating conditions.
Using data provided by sensors which monitor various engine functions (rpm, engine coolant temperature,
etc.), the microcomputer (ECM) triggers the spark at precisely the right instant.
(See IG section)
3. Idle Air Control (IAC)
The ECM is programmed with target idling speed values to respond to different engine conditions (engine
coolant temperature, air conditioning ON/OFF, etc.). Sensors transmit signals to the ECM which control
the flow of air through the by–pass of the throttle valve and adjust idle speed to the target value.
4. Diagnosis
The ECM detects any malfunctions and abnormalities in the sensor network and lights a Malfunction Indi-
cator Lamp on the combination meter. At the same time, the trouble is identified and a diagnostic trouble
code is recorded by the ECM. The diagnostic trouble code can be read by the number of blinks of the Mal-
function Indicator Lamp when terminals TE1 and E1 are connected. The diagnostic trouble codes are refer
red to the later page. (See TR section)
5. Fail–Safe Function
In the event of the sensor malfunctioning, a back–up circuit will take over to provide minimal driveability,
and the Malfunction Indicator Lamp will illuminate.
–ENGINE TROUBLESHOOTING SFI SYSTEM
EG–159
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