Volume Air Flow Sensor (Dohc) - Mitsubishi 1989-1993 GALANT Service Manual

FUEL SYSTEM <DOHC> -
VOLUME AIR FLOW SENSOR
Intake air amount
OPERATION
The volume air flow sensor is incorporated
l
within the air cleaner; it functions to convert the
amount of engine air intake to pulse signals of a
frequency proportional to the amount of engine
air intake, and to input those/signals to the en-
gine control module. The engine control module
then, based upon those signals, calculates the
amount of fuel injection, etc.
TROUBLESHOOTING HINTS
HINT 1:
If the engine sometimes stalls, try starting the en-
gine and shaking the volume air flow sensor har-
ness.
If the engine then stalls, incorrect or improper con-
tact of the volume air flow sensor connector is the
probable cause.
Hint 2:
If, when the ignition switch is switched ON (but the
engine is not started), the volume air flow sensor
output frequency is any value other than zero, a
malfunction of the volume air flow sensor or of the
engine control module is the probable cause.
Hint 3:
If idling is possible even though the volume air flow
sensor output frequency is deviated from the stand-
On-Vehicle inspection of MFI Components
<Turbo>
side
@Harness side
connector
Fnnine control module connector
The power for the volume air flow sensor is
l
ard value, the cause is usually a malfunction other
than of the volume air flow sensor.
Examples:
(1) The flow of air within the volume air flow sensor
(2) Incomplete combustion within a cylinder.
(3) Air is taken into the intake manifold through a
(4) Incomplete close contact of the EGR valve seat.
TSB Revision
The area enclosed with :I: is
applicable only for Turbo vehicle.
(Filter reset circuit)
connector
Engine control module
connector
supplied from the multiport fuel injection relay
to the volume air flow sensor, and is grounded
at the engine control module. The volume air
flow sensor, by intermitting the flow of the 5V
voltage applied from the engine control module,
produces pulse signals.
is disturbed. (Air duct disconnection or clogged
air cleaner element)
(Malfunction of spark plugs, ingnition coil, injec-
tors, compression pressure, etc.)
leaking gasket, etc.
injection relay
I