Mark Houlahan
Tech Editor, Mustang Monthly
January 10, 2014

The panel-based wiring concept preached by the Ron Francis folks means anyone, even Rusty, can wire his/her EFI engine project quickly and easily. The fuse panel and ECM mount wherever you find convenient—even all the way back in the trunk. Ron Francis makes this easy with a neat, compact panel. Then you simply follow the well written directions to connect your EFI engine's components (inputs and outputs) and route their un-terminated wire ends to the panel's location. Ron Francis gives each circuit 20 feet of high-quality automotive grade wiring that is labeled every 10 inches. Simply cut the wire to length, terminate the ends, and secure the wire ends to the panel. What could be easier? Follow along as we look over the installation as Rusty and his son, Brian, wire their very first EFI wiring system in the following photos.

13. With the 4.6L Two-Valve’s engine sensor and actuator wiring roughed in, it was time to move on to the electronically controlled automatic transmission, which also came from the Thunderbird. This is the connector for the Manual Lever Position Sensor (MLPS), which tells the computer where the manual lever is located so that neutral, start, and backup light circuits can be controlled. Since Rusty’s car does not have backup lights installed (he smoothed the rear valance), these wires were trimmed back and covered with shrink wrap.
14. Besides the MLPS connection, the 4R70W four-speed has two speed sensors and connections for the valve body. The rear most speed sensor, shown here, is the Vehicle Speed Sensor (VSS) and is used to tell the PCM road speed. The other speed sensor is for transmission shaft speed, but they use the same connector design, so don’t mix them up.
15. As wire bundles come together, more tie-wraps can be utilized to route the wiring together. Seen here is our initial engine bay bundle headed to the pass-through grommet now bundled with transmission and oxygen sensor wiring (roughly another 20 wires). The tie-wraps aren’t pretty, but they’re there just to keep things in order and to prove out the system (ensure the engine runs), and then Rusty will wrap all wiring with split loom.
16. Working toward the rear of the car, it was decided after a trial fit of the wire bundle that the EFI wiring could in fact be routed through the cowl side and along the door sill area. Trying to pass all wiring through at once proved too hard, but passing the wiring through the cowl side, past the door hinge plate, and into the sill area a few wires at a time got the job done.
17. From the door sill area the wiring traveled rearward through the quarter-panel (behind the quarter glass lower mounting bracket to prevent the regulator from pinching any wiring) and then up and over the right rear wheelhouse, ending in the trunk corner where the panel will be mounted.
18. The terminal locations are marked by removable plastic strips that protect the screw heads from any errant contact that might short a circuit. The instructions state to temporarily remove them for wiring (and show a diagram for proper reinstallation), but we found that if we simply released one end and swung them out of the way, that we could easily verify terminal location as we wired the panel.
19. While the instructions suggest routing each bag of wiring and terminating it at the panel before moving on, we felt it might be a more efficient use of time to have all of the wiring routed and then just sit back with the crimpers and install the terminals by wire number. There are a lot of wires to cut to length, strip, and crimp terminals to, so be sure to use quality tools. We suggest an automatic wire stripper and a ratcheting crimper to prevent over crimping.
20. As you complete the wiring circuits, the panel will start getting a little messy with wiring, but don’t worry, you’re not going to be utilizing every screw on the panel! As circuits are connected, bundle close wires together with more tie-wraps. Later, once the mounting panel has been fabricated, Rusty and Brian will further neaten the wiring at the panel and cover with split loom.
21. The system includes a few wire runs that actually begin at the panel versus ending at it. The circuits shown here are tach signal for an in-dash gauge, brake light switch, and the red and green wires are for an optional in-dash check engine light (there’s one located directly on the panel).
22. The final connections to be made will be the three heavy gauge wires attached directly to the panel. The red and black wires connect to the battery positive and negative terminals (Rusty has plans for a trunk-mounted battery, but it isn’t installed yet). The orange wire will attach to the ignition switch.
23. With all wiring complete, the PCM can now be connected. Depending upon the year of the PCM, it might require flash tuning to remove the Passive Anti-Theft System (PATS), as well as to turn off the EGR and other emissions functions. Ron Francis can do this for you, just discuss your needs with them at the time of ordering, or you can wait and have a local tuner perform the necessary programming.
24. The wiring for the 4.6L Two-Valve is much more compact now (for this build EGR, emissions, and rear oxygen sensors were eliminated), and there’s no worry about 17-year-old wiring, broken connectors, and the like. Once Rusty and Brian run the chassis harness, all of the wiring will be bundled and covered for an OE look.