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2015 Coyote wiring: light blue wire not needed?
Hello folks,
I have been working on this issue for a while now. I am working on getting the wiring done on my Mark IV with a 2015 Coyote engine. I am using the latest revision of the FFR instructions: Revision V (https://www.factoryfive.com/wp-conte...t-Roadster.pdf) -- page 95 is the relevant page for what I am working on. The instructions from Factory Five call for only using two wires from the 16-wire Coyote pigtail for the starter-- the ground wire, and the light green - ignition relay trigger wire (which connects to the orange coil wire from the RF harness. Other threads I have seen, and the Ford Performance instructions state that the light blue "Starter Motor Request" wire would also be needed, and I assume that needs to be connected to the blue "EFI Crank" wire from the RF harness. Am I correct in my understanding? Does that mean that Factory Five has an error in their instructions?
Thank you for any help, I have been digging for a solution for a while and I want to wire this properly before I attempt to start the engine.
Brian
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Senior Member
There are two ways to wire the start function. Controlled by the RF chassis harness start circuit, or controlled by the Coyote start circuit. In the instructions you reference, Factory Five is choosing the first one as indicated by the last line on the page: "We use the Non-PCM engine starting directions in the Ford Performance instructions. This uses the chassis harness starting wire to engage the starter."
What you are seeing from others is they are choosing the second choice, e.g. having the Coyote start function do the work. That means (1) Connecting the Coyote pigtail SMR to the blue "EFI Crank" wire as you indicated, (2) Connecting the Coyote harness start wire (Item N) to the small terminal on the starter solenoid and not the RF blue start wire, (3) Using the Coyote supplied bottom clutch switch as a safety interlock, (4) Ignoring the instructions on page 96 of the Factory Five instructions for a neutral safety switch with the RF blue wires. Those wires can be removed from the harness or just clipped off and capped.
FWIW, the second option using the Coyote start function is the better choice and also FWIW is how I wired mine.
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Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
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Post Thanks / Like - 1 Thanks, 1 Likes
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On a roll
I'll be brief: do what edwardb says... (it works)
Mk IV Roadster - #8650 - delivered 7-17-2015 - first start 7-28-2018 - first go-kart 10-13-2018 - licensed and on the road 9-9-19: body/paint completed 3-17-2020.
Complete kit / 2015 Coyote / TKO600 / IRS / Wilwood brakes / Mid-Shift mod / Power Steering / Heater and Seat Heaters / RT turn signal / Breeze radiator shroud and mount
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Senior Member
I'll add that I'm also going to do what edwardb suggests as well, having picked his brain on this very topic recently.
Last edited by shark92651; 07-16-2018 at 10:25 PM.
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EdwardB, you're something of a sage on the subject of the Coyote in an FFR car, so I am definitely following your advice.
I still don't think I fully understand how the FFR option would really work, but I'm fine with that, as the option you've laid out makes more logical sense to me anyway, so I don't need to fully grasp how the other way is intended to function.
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Senior Member
stalking this exchange. Now planning to do the same
Mk4 #9165, Base Kit with lots of options, Delivery on 08/17/2017, Coyote, TKO600, 2015 IRS, 18" Halibrands, 12.99" Wilwoods
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Senior Member
Originally Posted by
briankauf
EdwardB, you're something of a sage on the subject of the Coyote in an FFR car, so I am definitely following your advice.
I still don't think I fully understand how the FFR option would really work, but I'm fine with that, as the option you've laid out makes more logical sense to me anyway, so I don't need to fully grasp how the other way is intended to function.
Hmm... Don't know about the sage part. (Wise old man?? ) But did wire up a Gen 2 Coyote when they first came out and it's in its second driving season. Documented it and a number of builds have been successfully wired the same way. The Factory Five instructions, when released with the Gen 2 added, covered most of it. But left a few things a little unclear or optional. Like this one. Can be a little confusing.
The blue RF start wire goes to the small terminal on the starter solenoid through the safety switch in a standard installation, e.g. SBF. Like shown in the RF instructions and schematic. Using the Coyote start function is a little more advanced IMO and it's wired into the PDB and PCM so there's no downside at all. Won't spin the starter unless the bottom clutch switch is down. Also won't spin the starter if the ignition sense wire on the Coyote pigtail doesn't have +12V. Pretty much the starter won't spin unless the engine is going to start. Plus the function acts like a start button. You only have to make slightly more than momentary contact to the start position with the ignition switch and it cranks by itself until it starts.
Last edited by edwardb; 07-17-2018 at 01:51 PM.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
Build Thread
Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020.
Build Thread and
Video.
Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020.
Build Thread and
Video
Build 5: 35 Hot Rod Truck #138. LS3 and 4L65E auto. Rcvd 01/05/2021. Legal 04/20/2023.
Build Thread. Sold 11/9/2023.
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Hey folks! Thanks again for all the help. I realized that I also had to hook up the 3 red wires from the RF harness (wasn't explicitly stated in the F5 instructions, but they did show it in a photo). Was working on setting the fuel pressure regulator setting and accidentally started the car. Ran flawlessly. It's amazing how well these things start once the wiring is right. Thanks!!
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Senior Member
Originally Posted by
briankauf
Hey folks! Thanks again for all the help. I realized that I also had to hook up the 3 red wires from the RF harness (wasn't explicitly stated in the F5 instructions, but they did show it in a photo). Was working on setting the fuel pressure regulator setting and accidentally started the car. Ran flawlessly. It's amazing how well these things start once the wiring is right. Thanks!!
Do you mean the three large power wires on the RF harness? Those aren't unique to the Coyote wiring. Required for all builds so are in the RF wiring manual and schematic. But you're right. Once wired properly, the Coyote is usually anxious to get going.
Last edited by edwardb; 07-22-2018 at 12:34 PM.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
Build Thread
Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020.
Build Thread and
Video.
Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020.
Build Thread and
Video
Build 5: 35 Hot Rod Truck #138. LS3 and 4L65E auto. Rcvd 01/05/2021. Legal 04/20/2023.
Build Thread. Sold 11/9/2023.