MCi Crusader II 1989 Maintenance Manual page 248

Date 1-1-89
Page __
1_-_28 _ _
MC-9 MAINTENANCE MANUAL
SINGLE SENSOR SPEEDOMETER
WITH LEFT FRONT WHEEL TAKEOFF
DESCRIPTION
A single sensor type speedometer with left front wheel
takeoff is installed as standard equipment. The speedometer
head is installed on the left side of the instrument panel. A
single sensor is mounted on the backing plate on the left front
wheel. Also four capscrews are mounted 180° apart on the
backing plate.
OPERATION
As the left front wheel turns. the heads of the cap screws
pass under the sensor. The sensor simply "counts" the
number of times a cap screw head passes by. As they pass, a
pulse is generated and sent up the cable to the speedometer
head.
The gap between the sensor and cap screws is set at the
factory and should not require adjustment. However, if the
speedometer does not register at low speeds or high speeds.
the following procedure should be followed to correct the
situation.
PROCEDURE FOR CORRECTING SENSOR GAP
(A) Make sure all four cap screw heads pass approximate-
ly the same distance from sensor pickup.
(B) Start with a gap between sensor pickup and screw
heads of about 1/s" (3mm).
(C) Watch the speedometer needle on the instrument
panel as it slows down. The needle will begin to shake as the
speed decreases. When the indicated speed drops to seven to
five mph (12·9 km/h), the needle should suddenly drop to
zero. If it continues to display a reading below 5 mph (9 km/h)
the gap is too narrow and sould be widened slightly. If this is
not done, the needle may shake and become erratic at
highway speeds.
Conversely, if the needle drops to zero at 15 mph (23 km/h)
or more, the gap is too wide and sould be narrowed slightly.
When adjusting the gap. always recheck speedometer
reading to make sure the gap is increased or decreased
correctly.