Wiring Harness Check; Removal Of Strobe Sensor - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
c. WIRING HARNESS CHECK. (S/N 31-7852038 and up). This check utilizes a Hartzell Test Box B-4467
to provide assurance that the synchrophaser is properly connected. It also checks the functioning of the governor
solenoid coil and the pulse generators.
NOTE
These tests are to be made with all parts installed and connected to the
wiring harness except for the computer. Do not plug the computer in
until all tests have been satisfactorily completed.
1.
Connect the Hartzell Test Box B-4467 to the wiring harness in place of the computer.
2.
Turn the master switch ON. The Power light and Coil light should come on. Other lights may also be
on but they may be disregarded at this time with the exception of the Coil Short light. If it is on turn the master switch
OFF and refer to the following NOTE.
NOTE
If any of the lights on the test box fail to operate correctly, check the
wiring harness against the wiring diagram. Check for shorts, open
circuit breaker, broken wires and wires connected to the wrong pins.
3. Rotate the right engine by hand and watch the Right Engine light. If the light is off rotate the engine
until it comes on or vise versa. The engine may need to be rotated two revolutions to obtain a change. Repeat the
procedure for the left engine observing the Left Engine light.
4. Place the phase-manual switch in the manual position. The Manual light should come on and the
Phase light should go out. When the switch is placed in the phase position the opposite should occur.
5.
If the wiring harness checks good but the Right or Left Engine light or the Coil light does not
function properly replace the respective pulse generator or the governor.
6.
Timing engines with test box connected to the wiring harness rotate the right engine to the
desired timing position. Rotate the pulse generator housing until the Right Engine light just comes on. (You
will note that the light will remain illuminated for several degrees of rotation of the pulse generator housing but
the correct timing position is at the point where the light just comes on.) Lock the pulse generator into position.
Always turn both pulse generators in the same direction when timing unless they are driven in opposite
directions. Then the housings must be rotated in opposite directions. Repeat this procedure for the left engine
observing the left engine light.
14-139. REMOVAL OF STROBE SENSOR. (S/N 31-5001 thru 31-7852037). This unit is located in the
right engine nacelle, aft of the fire wall, at the upper right hand corner in the area between the nacelle skin and
the outboard nacelle bulkhead. (Refer to Figure 14-47.)
a. Remove the access panel on the outboard side of the nacelle just above the wing leading edge.
b. Disconnect the electrical connector.
c. Loosen the 1 inch hex nut at the front of the strobe sensor, that connects it to the dual tach
drive unit, and remove the sensor.
Reissued: 9/23/80
4111
ACCESSORIES AND UTILITIES