Mitsubishi 3000GT Service Manual page 359

TROUBLESHOOTING HINTS
Hint 1: Poor cleaning of exhaust gas will result if the heated oxygen sensor fails.
Hint 2: If the heated oxygen sensor checked good but the sensor output voltage is out of specification,
troubles of parts related to air-fuel raito control system are suspected.
[Examples]
(1) Faulty injector
(2) Air leaking into the intake manifold through gasket gap, etc.
(3) Faulty volume air flow sensor, intake air temperature sensor, barometric pressure sensor, engine
coolant temperature sensor
INSPECTION
Using Scan Tool
Function item No.
11
Data reading
39
L
<Heated oxygen sensor (rear)>
Function Item No.
Data reading 59
69
Function Item No.
Data reading 48
MULTIPORT
On-Vehicle Inspection of MFI
FUEL INJECTION - Components
Data display
Check condition
Sensor
Engine Warm-up
detection (Make the mixture lean by engine
voltage
speed reduction, and rich by racing)
Engine: Warm-up
(Using the heated oxygen sensor
signal, check the air/fuel mixture ra-
tio, and also check the condition of
control by the engine control mod-
ule)
Data display
Check condition
Sensor Transaxle: 2nd gear
l
voltage
Drive with wide open throttle
l
Data display
Check condition
Heater Engine: Warm-up
condition
Engine state
Standard value
When sudden 200 mV or lower
deceleration
from 4,000 rpm
When engine is
600 - 1,000 mV
suddenly raced
700 rpm 400 mV or lower
(Idling)
2,500 rpm
Engine
Standard value
condition
3,500 rpm
Engine Normal
condition indication
750 rpm (Idle) ON
5,000 rpm OFF