Mitsubishi 1989-1993 GALANT Service Manual page 423

FUEL SYSTEM <DOHC>
OPERATION
The crankshaft position sensor functions to de-
l
tect the crank angle (position) of each cylinder,
and to convert those data to pulse signals,
which are then input to the engine control mod-
ule. The engine control module, based upon
those signals, calculates the engine rpm, and
also regulates the fuel injection timing and the
ignition timing.
TROUBLESHOOTING HINTS
Hint 1:
If an impact is suddenly felt during driving or the en-
gine suddenly stalls during idling, try shaking the
crankshaft position sensor during idling.
If the engine stalls, the cause may be presumed to
be improper or incomplete contact of the crank-
shaft position sensor's connector.
Hint 2:
If the crankshaft position sensor output rpm is 0
rpm during cranking when the engine cannot be
started, the cause may be presumed to be a mal-
function of the crankshaft position sensor or a bro-
ken timing belt.
Hint 3:
If the indicated value of the crankshaft position sen-
sor output rpm is 0 rpm during cranking when the
engine cannot be started, the cause may be pre-
INSPECTION
Using Scan tool
l
current to intermittently pulse correctly, so a mal-
function of the ignition system circuitry, the ignition
coil and/or the power transistor is the probable
cause.
Hint 4:
If idling is possible even though the crankshaft posi-
tion sensor indicated rpm is a deviation from the
standard value, the cause is usually a malfunction of
something other than the crankshaft position sen-
sor.
Examples:
(1) Malfunction of the coolant-temperature sensor.
(2) Malfunction of the idle air control motor.
(3) Improper adjustment of the standard idling
Inspection conditions
. Engine: Cranking
. Tachometer connection
(Check intermittent flow of
ignition coil primary current
by tachometer.)
TSB Revision
The power for the crankshaft position sensor is
supplied from the ignition switch-IG and is
grounded to the vehicle body. The crankshaft
position sensor, by intermitting the flow (to
ground) of the 5V voltage applied from the en-
gine control module, produces pulse signals.
speed.
Description
Compare cranking
rpm and scan tool
indicated rpm.
At 40°C (104°F) 1 ,OOO- 1,250 rpm
At 80°C (176°F)
Normal condition
Both agree.