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Fuel Flow Tester instructions.

September 05, 2012 by Craig Peyton

Fuel Flow Tester Instructions

The JPI fuel flow tester helps diagnose problems associated with the fuel flow options of the FS-450 or the EDM-700/711/800/760/900/930/1000C engine monitoring system. The fuel flow tester temporarily replaces the transducer and simulates the pulses generated by the fuel flow transducer. This allows the aviation technician to isolate a problem to the cable, instrument or the transducer.

To use the fuel flow tester, perform the following steps.

1. Disconnect the fuel flow transducer from the fuel flow cable by pulling apart the connectors near the fuel flow transducer.

2. Plug the cable connector into the fuel flow tester.

3. Turn on the FS-450 or the 700/711/800/760/900/930/1000C

4. Use the checklist below to troubleshoot the problem:

*Symptom*	*Problem*
Red LED indicator on fuel flow tester does not light.	Check the fuel flow cable for continuity from the instrument to the transducer end. FS-450: 12 volts between pins 5 and 3 on FF connector. EDM-700: 12 volts between pins 5 and 6 on FF connector. EDM-760: 12 volts between pins 5 and 6 on FF connector. EDM-900/930/1000C: 12 volts between pins 5 and 6 on theP4 FF connector.
The FS-450 or EDM displays a positive rate of fuel flow with the fuel flow tester, but not with the fuel flow transducer. If the K-factor is approximately 19,000 (19.00=KF), the correct rate shown on the display should be between 18 and 20 GPH. If the K-factor is approximately 29,000 (29.00=KF), the correct rate shown on the display should be between 12 and 14 GPH.	If the reading on the display is in the correct rate range, then the fuel flow transducer is most likely defective. Return for repair or replacement. The instrument is okay. **If some other K-factor transducer is used, the display should read approximately the value resulting from dividing 360 by the K-factor. For example: 360/85.00 = 4.2 displayed.
The FS-450 or EDM displays a zero or erroneous rate of fuel flow with the fuel flow tester as well as with the fuel flow transducer.	Check that the K-factor is correct. If it is, the instrument is most likely defective. Return the instrument only—not the transducer—to the factory for repair.