Engine Sensor Wiring

Tonight I wired up the Manifold Pressure, engine oil temperature, and fuel pressure sensors. I wanted to finish the job and wire up the oil pressure sensor, but I ran out of butt splices. I tested the sensors by powering up the instrument panel and looking for signals. I was happy to see all of the gauges reporting data correctly.

I also took the opportunity to test and adjust the canopy unsafe warning. At first the canopy pins weren’t contacting the micro switch, but after a quick adjustment it now works great.

Oil temperature sensor wiring
Typical connection between sensor and wiring harness. I used butt splices because I don’t want these to come apart in-flight, and I have plenty of wire length to allow cutting and re-doing this if I even need to replace the sensor

Manifold pressure line

Tonight I installed the cushion clamps to secure the manifold pressure line, and the rubber hoses to route pressure to the e-mags.

I found I had to make an adjustment to the routing of the line, so I removed the engine-side connector, rerouted, then reconnected the line. That also led to moving some clamps around, but I think I have a good routing now. Once the oil cooler scat tubing is installed I may have some interference, but I’ll deal with that later.

Installing the rubber tubes was kind of a pain, as access to the mags is somewhat restricted. But I get the feeling it will be even worse when I have to do some wiring back there.

Rerouted line to work around the engine mount
The rubber hoses installed
Final routing on the left hand side

Oil Pressure and Manifold Pressure

Tonight I installed the oil pressure sensor line, and started on another modification to move the manifold pressure sensor. This modification is courtesy of Steve at Aircraft Specialties and makes use of the unused port on the Vans bracket. It’s a more elegant solution for providing manifold pressure to the two E-mags, in my opinion.

The oil pressure line was straight forward, just connecting two fittings with a hose, and torquing the b-nuts.

The manifold pressure line was slightly more involved. First uninstalled the pressure sensor from its original location on the right side of the firewall, and reinstalled it on the left side, using the spare port. I hunted around and found a spare plug, and then installed that along with the Aircraft Specialties supplied fluid fitting. I made up the rest of the fittings, routed the lines across the engine compartment and installed the line at both ends. Now I just have to locate and install the cushion clamps to secure it in place.

Oil pressure line connected and torqued
Manifold pressure line routed across the top of the engine compartment. The two needle fittings will connect to the two e-mags using lengths of rubber hose
The lines routing to the Vans bracket
Top-down view of the Vans bracket. The fitting on the right is a straight fluid fitting, despite looking like it’s 45 degrees in this picture. Sensors from left to right: oil pressure, fuel pressure, manifold pressure

Fuel lines

Tonight I finished installed the remaining fuel lines, torquing them and marking with torque seal. With that, the fuel system is plumbed from the wing root, through the fuselage, firewall, engine-driven fuel pump, fuel transducer, fuel control, fuel spider, and out to each injector. Once the wings are installed, the final piece is the short connection from the wing root to the fuel tank.

This felt like a bit of a milestone, so I took a selfie from under the engine.

Firewall exit. After fretting about clocking this fitting to 5 degrees, I have no idea why that clocking is even necessary. Perhaps it’s related to the EXP engine changes
Fuel pump connection
Fuel controller connection
Looking up from under the engine