Mitsubishi 1992 3000GT, Service Manual

Page: 136 / 1308

FUEL INJECTION
LIST OF FAIL-SAFE/BACK-UP FUNCTIONS
When the failure of a major sensor is detected by the on-board diagnostics, the preset control logic
provides controls to assure safe operation of the vehicle.
Trouble item
Controls to be provided in the event of trouble
Volume air flow
(1)
sensor
Based on throttle position sensor (TPS) signal and engine speed signal (crank angle
signal) basic driving time of injectors and basic ignition timing is read from the prese
map.
(2) Idle air control motor fixed at predetermined position, and no idling speed control
Intake air
ature sensor
Controls provided on the assumption that intake air temperature is (77°F)
Throttle position
sensor (TPS) No additional fuel injection provided on the basis of throttle position sensor signal at acceleration
Engine coolant
temperature Controls provided on the assumption that engine coolant temperature is 80°C (176°F) (Even if
sor
the sensor signal returns to normal, this control mode is retained until the ignition switch is set to
OFF.)
Camshaft
position sensor (1) Fuel injected into the cylinders in the order l-2-3-4-5-6 with irregular timing
(Provided that no No.1 cylinder top dead center position has been detected since
ignition switch was placed in the ON position)
(2) Fuel cut 4 seconds after a failure was detected
(Provided that no No.1 cylinder top dead center position has been detected since
ignition switch was placed in the ON position)
Barometric
sure sensor
Knock sensor
Ignition coil and
ignition power
transistor unit
Controls provided on the assumption that barometric pressure is 101 (760 (sea level)
Ignition timing is changed from that for premium gasoline to that for regular gasoline.
Fuel cut for cylinders whose ignition signal is abnormal
Communication
line with
mission control
module No ignition timing retard control (overall engine-transmission control) achieved when
sion speeds are changed
oxygen
sensor (front)
No air-fuel ratio closed loop control achieved
models>
Heated oxygen
sensor (rear)
Only signals of oxygen sensor (front) installed upstream of catalyst are used, and the air-fuel ratio
cl994 and later
feedback control (closed loop control) is not performed.
California model>
TSB Revision