Mitsubishi Eclipse 1990 Service Manual page 552

Code No. Fuel Trim Malfunction (Bank 1)
[Comment]
Background
If a malfunction occurs in the fuel system, the fuel compensation value becomes too large
or too small.
The engine control module checks whether the fuel compensation value is within a specified
range.
Check Area
Under the closed loop air-fuel ratio control
Intake air temperature is
Barometric pressure is 76
Judgement Criteria
Long-range fuel correction has continued to be not lower than
-12.5% for 10 sec.
Short-range fuel correction has continued to be not lower than
-10.0% for 10 sec.
SCAN TOOL Data list
13 Intake air temperature sensor (Refer to
SCAN TOOL Data list
21 Engine coolant temperature sensor (Refer to
SCAN TOOL Data list
25 Barometric pressure sensor (Refer to
Check the injector (Refer to
Check the following connectors:
Check the fuel pressure (Refer to
SCAN TOOL Data list
81 Long-term fuel compensation (Refer to
fuel trim more or less than zero?
sensor
(Refer to
Does the tester indi-
cate more than the
standard value?
Yes
Replace the volume air
flow sensor.
ENGINE (TURBO)
AND ENGINE>
or higher
(11 psi.) or higher.
OK
OK
OK
N
OK
OK
I
Check for fuel leaking
from injectors.
Check for contamina-
tion (water, kerosene,
etc.) in the fuel.
OK
Replace the ECM
TSB Revision
Troubleshooting
Probable
or not higher than
or not higher than
NG
Check the intake air temperature circuit malfunction. (Refer to
INSPECTION PROCEDURE
TROUBLE CODE
NG
Check the engine coolant
to INSPECTION PROCEDURE
TROUBLE CODE
NG
Check the barometric pressure circuit
INSPECTION PROCEDURE
TROUBLE CODE
NG
Replace
G
Repair
NG
Repair
More
than zero
Check if air was drawn
into the intake
OK
SCAN
12 Volume air flow sensor
(Refer to
Does the tester indi-
cate less than the
standard value?
1
V o l u m e ' a i r
Injector failed
Incorrect fuel pressure
Air drawn gaps
Heated oxygen sensor
Engine coolant temperature sensor failed,
Intake air, temperature sensor
f a i l e d
Exhaust gas leaks
E n g i n e
malfunction (Refer
DIAGNOSTIC
NG
Repair
No
Check for blocked
injectors.
Check for fuel filter
and fuel line block-
ages.
Check the fuel pump
(insufficient
charge).
Check for exhaust
gas leaks (oxygen
sensorfitting, exhaust
manifold cracks, front
pipe cracks, etc.)
Check for contamina-
tion (water, kerosene,
etc.) in the
OK
Replace
.
seals,' etc.
dis-