Fuel Pressure Sender Testing - Piper PA-44-180 SEMINOLE Maintenance Manual

FUEL PRESSURE SENDER TESTING. (Refer to Chart 7301.)
The fuel pressure sender works on the relationship of pressure to resistance. As the pressure rises the
r e s i stance rises and alters the position of the needle in the instrument.
1. The sender may be tested by removing it from the aircraft and applying a calibrated pressure to the
pressure port.
2 . Attach an ohmmeter to the two terminals on the reverse side of the pressure port, and check the
r e s i stances as shown in Chart 7301 .
3 . To test the sender and gauge in conjunction with each other, disconnect the gauge from the aircraft
s y stem, connect it in series (using a 12 to 14-volt system) with the sender, and proceed as follows:
A. Slowly increase the pressure to the sender till 9 + 0.5 psi is reached.
B. Let the system set at the pressure for a couple of seconds, recheck the pressure, and lower the
pressure to 8.0 psi.
C. Reduce the pressure to 0.5 psi. The gauge should indicate 0.5, +1, - 0 needle widths.
The sender and gauge are nonadjustable, therefore that which
does not meet specifications should be replaced.
4. Reinstall the gauge and sender.
CHART 7301. FUEL PRESSURE SENDER TEST SPECIFICATION
Pressure (Psi)
0
.5
5
8
10
The gauge (Piper P/N 86750-2) should indicate 8 psi +1/2. - 0 needle widths.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— NOTE —
Resistance (Ohms)
10
11.5
42
60
72
3F12
Tolerance (Ohms)
—
+1, - 0
±1
+1/2, - 0
±1
73-30-02
Page 73-09
Revised: May 15, 1989