Mitsubishi Stealth 1994 Import Service Manual page 520

MULTIPORT FUEL INJECTION -
VOLUME AIR FLOW SENSOR
Volume air flow sensor
OPERATION
The volume air flow sensor located in the air cleaner converts the engine intake air volume into a pulse
l
signal of frequency proportional to the air volume and inputs it to the engine control module, which then
computes the fuel injection rate, etc. based on the input signal.
The volume air flow sensor power is supplied from the MFI relay to the volume air flow sensor and is
l
grounded in the engine control module. The volume air flow sensor generates a pulse signal as it
repeatedly opens and closes between the 5 V voltage supplied from the engine control module and
ground.
TROUBLESHOOTING HINTS
Hint 1 : If the engine stalls occasionally, crank the engine and shake the volume air flow sensor harness. If
the engine stalls, poor contact of the volume air flow sensor connector is suspected.
Hint 2: If the volume air flow sensor output frequency is other than 0 when the ignition switch is turned on
(but not starting the engine), faulty volume air flow sensor or engine control module is suspected.
Hint 3: If the engine can be run idle even though the volume air flow sensor output frequency is out of
specification, troubles are often found in other than the volume air flow sensor itself.
(Disconnected air duct, clogged air cleaner element)
(2) Poor combustion in the cylinder
(Faulty ignition plug, ignition coil, injector, incorrect compression pressure, etc.)
(3) Air leaking into the intake manifold through gap of gasket, etc.
Loose EGR valve seat
(4)
On-Vehicle inspection of MFI Components
r
connector
connector
Engine control module connector
Volume air flow sensor
4
Engine
control
module