Thursday, February 18, 2016

Primping & Crimping – A “Crimp Fest” Day

It was good to get back to the hangar and make some forward progress on the RV-12 after waiting out the cold snap and also dealing with two vehicles that needed repairs. Gee, what are the odds of having two vehicles and both of them needing sudden repairs simultaneously? Apparently quite good … considering they are 24 and 21 years old.

The first task for the day was to complete the wiring for the oil pressure sensor plug and to provide a ground for the sensor. As mentioned in the previous post, rather than splicing the WH-00096 it was determined the wires were long enough to be connected directly to the firewall forward connector. Normally P-765 (a red wire from pin 6 on the firewall forward connector) would be spliced to the red wire in the WH-00096 wire harness and E-764 (a white/yellow from pin 15 on the firewall forward connector) would be spliced to the white wire in the WH-00096 wire harness. To accommodate the wiring change, the red wire on pin 6 and white/yellow wire on pin 15 of the firewall forward connector were removed and male connector pins were crimped onto the red and white wires in the WH-00096 wiring harness.

After using a pin removal tool to successfully pop the pins out of the connector body, not wanting to cut the green heat shrink covering the wires in the connector, the two wires were plugged into spare wires with a female connector pins and pushed out of the heat shrink. The reasoning behind this was so the old wires could be pushed out and the new wire could follow the same path back through the shrink wrap. Once the new wires were in position, the red wire in the WH-00096 harness was inserted into position 6 and the white wire was inserted into position 15 of the firewall forward connector.  After the wires were locked in place, the connector’s shell was reinstalled and the firewall forward connector was plugged back into the control module.
The yellow wires with the blue and red stripes on the left have female connectors on the end of them and were used to help push the old wires out of the shrink wrap thus creating a return path for the new wires. The new red and white wires in the WH-00096 wire harness are now plugged into the female connectors and about to be pulled back through the shrink wrap on the connector.  This method worked out quite well.

For the oil pressure sensor grounding, the oil pressure sensor was removed from the adapter fitting so a ring connector could be sandwiched between the sensor and the adapter. The new ground wire was run over to the handy ground block (a modification on the DOG Aviation RV-12).

With the wiring for the oil pressure sensor completed, moved on to the wiring for the manifold pressure sensor. There are three wires that connect to the manifold pressure sensor via a Weatherpack connector … pin A is a ground, pin B is the signal wire and pin C is +5 volts. The three wires in the firewall forward wiring harness already come with male Weatherpack pins crimped on them. Wanting to ground the unit directly to the grounding block, I have been keeping my eyes open for male Weatherpack pins to make a short ground wire to connect directly to the ground bock on the firewall. While at the auto parts store getting parts for one of the vehicles, ended up purchasing a wire that had a male Weatherpack pin already on it.

It has been quite a while since the inventory had been done on the engine kit, so I had forgotten that Dynon included male Weatherpack pins along with the Weatherpack connector housing. I had remembered seeing the connector … but not the pins included. So it came as quite a shock to see a package of male Weatherpack pins accompanying the Weatherpack plug housing … especially after having just purchased a wire the day before that had a Weatherpack pin on it.
The Dynon supplied Weatherpack connector body with pins (which normally will not be used because Van’s wiring harness already has male Weatherpack pins crimped onto the wires) and the single wire purchased locally that came with a male Weatherpack pin.

I connected the purchased black wire to position A (this is the ground wire and will run to the ground block).  E-751 (green/red) manifold pressure wire is inserted onto position B and P750 (white/red) power wire is inserted into position C of the Weatherpack plug housing. Here again, similar to the ignition module connectors, it is necessary to hold the wire at the rubber seal while inserting the wire into the connector’s body … when the rubber seal was flush with the body, I used a chunk of popsicle stick to push the rubber seal in a little further until the pin made a “click” sound as the pin locked in place.
About to insert the ground wire into position A. Note on the male Weatherpack pin how the rubber seal is also the strain relief for the wire. While inserting the male pin into the connector’s body, the wire should be held with fingers touching the rubber plug to prevent it backing out of the ring that holds it while the pin is inserted.
The completed wiring for the manifold sensor on the left and the newly attached yellow ground ring attached to the oil pressure sensor on the right can be seen here. Both these units are now grounded to the grounding block under the manifold sensor module.

After the manifold pressure wiring was primped and neatly wire tied, continued on with the “crimp fest” now paying attention to the wires which were routed previously for the left and right cylinder head temperature sensors (CHT) and the oil temperature sensor. The wires were primped and wire tied in position and ES-640903-2 female spade connectors were crimped onto the ends of the three wires. An addition, I used a small piece of heat shrink tubing over the CHT wires where they cross over the metal hose clamps on the water lines they ride on.
Both CHT wires were wired as the one in this photo. Note the addition of a small piece of heat shrink to protect the wire where it passes over the metal hose clamp.