Engine Indication Troubleshooting - Garmin G3X Installation Manual

1. Inspect GSU73 pitot/static plumbing integrity.
2. Inspect pitot/static ports and associated equipment.
3. If the problem persists replace the GSU 73 with a known good unit.

10.4 Engine Indication Troubleshooting

To troubleshoot an Engine Indication failure (Figure 10-3), gather answers to the following
questions. This information may be helpful to the installer/pilot, the G3X Dealer, or to Garmin
Aviation Product Support in troubleshooting the failure.
Figure 10-3 –Engine/Airframe Failure Indications
1. Does cycling power restore operation?
2. Did the operator give it sufficient time to start and initialize?
3. Did the problem begin after a software or configuration load?
4. Did the problem happen on the ground or while airborne?
5. Is only the EGT/CHT (i.e. thermocouple inputs) Red-X'd? If so, the GSU 73 configuration
module, configuration module wiring, thermocouple reference, or applicable thermocouple is
defective. Check the wiring and replace the configuration module or applicable
thermocouple.
6. Are there one or more temperatures that drop as the electrical load increases? If a
temperature probe shorts (usually where the bayonet is crimped) a ground loop is created
forcing the reference (low side) to increase which causes the temperature reading to decrease.
7. Does the EGT temperature slowly drift up and eventually flag? This is an indication of an
(electrical) open in the temperature probe or wiring.
8. Is the air data information on the PFD intermittently Red-X'ing? If the GSU 73 +5VDC
transducer power supply is shorted to ground, it will cause an intermittent air data Red-X
issue to occur.
9. If the AMP indication is Red-X'd, check the Alternator Shunt for correct resistance. Refer to
the applicable sensor documentation.
10. If the Position Indication is Red-X'd, check the sensor and wiring.
11. For single wire temperature inputs, ensure that the LO input pin is tied to ground as close as
is practical to the sensor, grounding the LO input pin away from the sensor may result in
inaccurate or invalid readings.
Page 10-4
Revision E
(Reversionary or Split-Screen PFD)
G3X Installation Manual –Troubleshooting
190-01115-01