Frequently Asked Question

Cause:

1. The incorrect sensor is installed.
2. The ground to the sensor is open.

Troubleshooting

1. Verify the sensor is the correct sensor by They can be identified by their one or two terminals on the side opposite the pressure connection. The sensor will be stamped with its pressure range and brand on the flats used to tighten the sensor, at the pressure port end. A 30 psi sensor is also marked 0-2 Bar, 80 psi is also marked 0-5 bar, and 150psi also marked 0-10 Bar.
2. See sensor is wiring can be verified by temporarily configuring the auxiliary input as a sensitive voltmeter by setting the following items on the configuration set pages:

• Set the forward/reverse sensing to forward (+ on the options page for the input the fuel pressure sender is connected to.)
• Set the AUXSF to 250
• Set the AUXOFF to 0

The auxiliary display should now show 5-20 if the wiring is correct. (If the auxiliary is displayed with a decimal point, it should show 0.5 – 2.0).

If the auxiliary display shows 0, the connection to the auxiliary input is open, or the 4.8V excitation is open, or the resistor is the wrong value (too large).

If the auxiliary display is greater than 450 (45.0 if the auxiliary is displayed with a decimal point), the sensor ground is open, the 4.8V excitation was wired to the sensor without the resistor inline, or the sensor has failed.

If the auxiliary display is in the range of 20-450 (2.0 - 45.0 if the auxiliary is displayed with a decimal point), the resistor value may be incorrect. A simple way to measure this resistor can be to disconnect the 25-pin d-sub connector from the EIS, and measure the resistance to ground through the 4.8V output pin in the connector on the aircraft wiring. If only the fuel pressure sensor is being powered by the 4.8V output, the resistance measured will be about 10 ohm greater than the value of the resistor installed in the 4.8V output line. (If multiple devices use the 4.8V output, disconnect the ground to the other devices when making this measurement.)

Upon completion of this test, reset the auxiliary input and scale factor the to values specified on the fuel pressure diagram.