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G900X EGT/CHT fluctuating temps

mynameisSean123

mynameisSean123

Member
Hey everyone, hoping to get some help.

I have a G900X that recently the EGT/CHT both have recently been fluctuating +/-150 degrees and sometimes goes down to nothing all together.

The engine runs fine, never looses power, never problems.. just the temps.

I checked as many wires as possible to look for a loose connection somewhere, but everything looked good

Any ideas?

Trying to add a video, but it wont let me.

Thank you
 
G900X EGT/CHT fluctuating temps??

Hey everyone, hoping to get some help.

I have a G900X that recently the EGT/CHT both have recently been fluctuating +/-150 degrees and sometimes goes down to nothing all together.

The engine runs fine, never looses power, never problems.. just the temps.

I checked as many wires as possible to look for a loose connection somewhere, but everything looked good

Any ideas?

Trying to add a video, but it wont let me.

Thank you
 
I'd look in the manual for the sensor circuit and see what else is on it. Chances are you have a bad connection somewhere but there is no easy way to trouble shoot it. A call to Garmin might be in order.

-Marc
 
wiring and connection issues are top of the list. The work in micro volts and quite sensitive to flaws. However, if running unshielded sparkplug wires with auto plugs (higher resistance than aviation plugs), then adequate spacing must be maintained from thermocouple wires. I had exactly that issue. moved things around to make sure I kept an inch spacing and problem went away.
 
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In addition to looking for loose connections... Given that only the thermocouple sensors seem to be affected, I would look for problems with the thermocouple reference junction at the GEA 71.
 
Like Matt said, look at the reference thermocouple connected to pins 68 and 69 on GEA71 connector P701. The thermocouple is located inside the connector backshell.
 
An errant ground can cause issues. I had a similar issue long ago with my G900X. I seem to remember that being the cause for me.
 
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