Engine Sensor Wiring (10)

 10 hours

Once I pretty much had the firewall forward wiring figured out, I figured I should do all the engine sensors next.  That way I'd have pretty much everything that penetrates the firewall done.  Here's a list of all the engine sensors feeding into the GEA 24 (engine interface box):

CHT Thermocouples x4

EGT Thermocouples x4

Turbo Temp Thermocouple

Oil Temp

Oil Pressure

Manifold Pressure

Fuel Flow

Fuel Level

Ammeter

RPM

It doesn't really seem like a whole lot but it adds up to a lot of wires!  By far the most time consuming of these was all the thermocouples.  Each thermocouple has two wires, each with fiberglass insulation, and then the pair is also covered in more fiberglass insulation.  Wire strippers don't really work on the fiberglass, so for each wire I had to manual pick the fiberglass apart and snip it off to expose the ends to connect.  On top of that, 7 out of the 9 thermocouples had to be extended to reach the GEA 24, so I had to pick up some extra thermocouple wire and some special connectors.  30 feet of extra wire ended up being the right amount; it was plenty and I didn't have a whole lot left over.  Here are links to the wire and connectors I bought:

Thermocouple Wire

OLC-2 Connectors

The CHT and EGT thermocouples all went to one of the four connectors on the GEA, so I was able to assemble that connector and call it done.

The next connector includes RPM, the turbo temp thermocouple, ammeter, oil temp, fuel flow, and the oil and manifold pressures.  All of these, except the thermocouple, require shielded wire with the shield grounded to the connnector backshell.  I had no idea what any of that meant until I studied the G3X manual quite a bit and found this video from Garmin that shows how to solder the shields: https://www.youtube.com/watch?v=jmVLVhGoGQs

Actually, this playlist pretty much covered all the soldering and connecting methods that I needed to learn, so that was super useful:  https://www.youtube.com/playlist?list=PLTucYQ1EkW8f7bXkGRWvb2OEE80BFRMTF

Anyway, after doing it a couple times the shields were pretty easy to deal with.  The oil and manifold pressure sensors, and fuel flow sensor, all came with 3-wire pigtails that I extended with 3-wire shielded wire to connect to the GEA 24.  The ammeter, oil temp, and RPM wires I just made from scratch.

I soldered in some tiny 1A fuses to the ammeter shunt wires