Extend engine wire harness Gen 3 Coyote

[Real Time]

Hi, I would like to insatall the PCM for my Coyote Gen 3 behind the dash with the connection ports protruding through the fire wall into the engine bay. The Engine Harness will not reach this location without modification. I'd venture to think if I called FORD they would tell me that extending any harness wiring is not recomended. It would be nice if I opened the harness and there was slack to give me what I need. Does anyone have any experience with this?
Any help greatly appreciated.

[Indy Shu]

I think someone has done it. There's not much room behind the dash to begin with. If you have ac the ducting needs a lot of space. The PCM is fairly large and would likely be sticking out of the firewall a few inches into the engine bay. I don't think the harness would be a problem. I have mine mounted in the middle of the firewall and only had to extend the throttle body harness (I bought and extension harness for that) and maybe one other. You wouldn't be any worse.

[Alan_C]

They did it at Dave Kindig's shop a while back, *****in Rides season 7 episode 1, Easy Does It. They put a Gen 3 Coyote into a 65 Mustang Fastback. Not a lot of the episode devoted to the wiring, but there are a few seens in there where Dave is impressed by the number of wire in the harness.

[edwardb]

I've heard of guys unwrapping the Coyote engine harness from the stock location and allowing it to be extended backwards. But the Gen3 has even more wires with the direct injection. On a Roadster, the PCM can be installed on the outside of the hood frame and is basically hidden once the body is on. If you get the Coyote installation package from FFR, they provide the mounting bracket for this location. Without extending any wires. I'm pretty adventuresome, but wouldn't attempt to extend any of the PCM wires. This picture is the Gen2 build in my 20th Anniversary Roadster. But the Gen3 would be the same.

https://hosting.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Coyote%20Engine/.highres/IMG_0468_zps7a0sla3k.jpg?width=590&height=370&fit=bounds (https://hosting.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Coyote%20Engine/.highres/IMG_0468_zps7a0sla3k.jpg?width=590&height=370&fit=bounds)

[JohnK]

+1 to what Edwardb said. I'd mount it in the FFR-recommended location with the provided bracket. It's a good spot. No reason I can think of to reinvent this wheel. I did unwrap a good amount of the coyote harness to relocate wires, and that might provide you with some freedom to move things around, but IMO trying to extend wires is just asking for tough-to-diagnose electrical gremlins down the road. If you decide to unwrap/re-wrap, buy some non-adhesive vinyl harness wrap and you can re-wrap the harness to look just like OEM.

[Nigel Allen]

X2 on what Paul said. There are at least 70 wires in my gen 1 loom. Each extension requires 2 joins, so that's at least 140 joins. I am sure there are many morewires in the gen 3 looms. I am a keen and confident sparky, but would wuss out on making that many joints in one loom. Physical limitations would also be problematic with that many joints in a short loom.

Nigel

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[Real Time]

I think someone has done it. There's not much room behind the dash to begin with. If you have ac the ducting needs a lot of space. The PCM is fairly large and would likely be sticking out of the firewall a few inches into the engine bay. I don't think the harness would be a problem. I have mine mounted in the middle of the firewall and only had to extend the throttle body harness (I bought and extension harness for that) and maybe one other. You wouldn't be any worse.

All good with the space for the PCM behind the firewall. Could you tell me where you purchased the harness extension for the Throttle body?

[Real Time]

If heard of guys unwrapping the Coyote engine harness from the stock location and allowing it to be extended backwards. But the Gen3 has even more wires with the direct injection. On a Roadster, the PCM can be installed on the outside of the hood frame and is basically hidden once the body is on. If you get the Coyote installation package from FFR, they provide the mounting bracket for this location. Without extending any wires. I'm pretty adventuresome, but wouldn't attempt to extend any of the PCM wires. This picture is the Gen2 build in my 20th Anniversary Roadster. But the Gen3 would be the same.

https://hosting.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Coyote%20Engine/.highres/IMG_0468_zps7a0sla3k.jpg?width=590&height=370&fit=bounds (https://hosting.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Coyote%20Engine/.highres/IMG_0468_zps7a0sla3k.jpg?width=590&height=370&fit=bounds)

Looks beautiful! I have the Install package from FFR. I have the room behind the firewall and seems pretty simple to put it there. (Barring any issues with the need to extend wires.....lol). It just seems much easier to access should there ever be an issue with it. Your input is greatly appreciated!!!

[Indy Shu]

All good with the space for the PCM behind the firewall. Could you tell me where you purchased the harness extension for the Throttle body?
Ballenger motorsports https://www.amazon.com/Ballenger-Motorsports-Connector-Extension-Compatible/dp/B08K3G4WKT?th=1

[Real Time]

Ballenger motorsports https://www.amazon.com/Ballenger-Motorsports-Connector-Extension-Compatible/dp/B08K3G4WKT?th=1

Thank you !!