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Thread: Coyote Donor ECU Question

  1. #1

    Coyote Donor ECU Question

    I searched, I must be using the wrong words.

    I live in MA and MA is a pain to get kit cars legal which is ironic due to FFR being in MA. In MA it seems much easier to get the car on the road if the engine/trans came from a donor car. If I bought a 5.0 coyote mustang and harvested the engine/transmission and ECU would it work in a complete kit from FFR? Will the mustang ECU throw a fit due to no longer being in a mustang?

    Thank you.

  2. #2
    Very difficult to do it that way. Also I don't think the transmission will fit. Your better off buying a crusher car than going through that headache.

  3. #3
    Senior Member CraigS's Avatar
    Join Date
    Feb 2011
    Manassas, Va.
    Modern cars make it difficult to use their efi system since so many other systems are tied into it. Cruise control, ABS, stability control, sound system, AC, are five that quickly come to mind. One option that 'might' help would be to buy a donor engine (w/ receipts to prove that) and then buy the Ford control pack to replace the donor electronics.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

  4. #4
    Quote Originally Posted by michael everson View Post
    Very difficult to do it that way. Also I don't think the transmission will fit. Your better off buying a crusher car than going through that headache.

    This is good Advice. Buying a later donor car is tough. You will have to make all emissions work for that car. Including PCV, EGR, Evaporative emissions etc. etc.

    Crusher car is the way to go.

    Send me a PM if you like and we can exchange numbers and talk this through. its very doable. You just need to plan and understand your options.
    FFinisher/AKA RE63

  5. #5
    Several have tried to use the donor Mustang harness and ECU with the Coyote. It can be done, but I've seen where several gave up. You have to keep most of the wiring and components in the circuit as CraigS mentioned or it won't function. Including the Passive Anti-Theft System (PATS) or some places can apparently program this out. You're way better off, as mentioned, getting the Ford Performance control pack. Simple, neat, clean and it works. The main issue with the Mustang MT-82 transmission is the shifter location. It's a foot or so behind where it needs to be for these builds. Some have fabricated solutions. Just know what you're signing up for. Also make sure to get a later model if you go that way. Early MT-82's had some issues that Ford has apparently addressed.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
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  6. #6
    Regarding PATS,
    This may be different in modern cars, but PATS is disabled in the ECU in my truck (2001) and while it does not immobilize the truck it does blink trouble codes on the dash, so disabled more so than removed.

  7. #7
    Senior Member Duke's Avatar
    Join Date
    Dec 2015
    Here yea go. Just went through this a few months ago.

  8. #8
    We only use donor Mustang drive trains. We have built 2 thus far, one Mk IV and one coupe. We use the Mustang transmission and diff. A couple of things that are required to do this: the Mustang shifter is about a foot too far aft. To address this we developed a top loading shift mechanism that bolts to the top of the tranny. It also requires building a non traditional drive shaft as it bolts to flanges on both ends. As for using the Mustang ECU, we have never tried. We modify the engine harness and use and aftermarket ECU and a coil driver that we developed internally. You certainly can use the Ford Performance ECU. The advantage of the ECU that we use is that we get traction control, lunch control, flat foot shifting, and variable drive modes (i.e. track or performance vs. cruise mode) and of course flex fuel. These features are not available with the Ford Performance ECU.

    We are about a month away from being able to offer the shift mechanism and drive shaft for sale. For your reference, our shifter includes the following:

    • FormaCars Billet top mount shifter assy
    • FormaCars Billet reverse lockout collar
    • FormaCars Mark IV or coupe rear transmission mount
    • FormaCars Mark IV or coupe tunnel sheet metal for MT82
    • FormaCars Shift boot for MT82
    • FormaCars Billet shift boot trim for MT82

    You’ll need from your donor transmission:
    • Shifter lever
    • While reverse lockout sleeve, spring & screw
    • Shift knob (or aftermarket Mustang shift knob)

    As for the ECU we can probably help you with integrating our solution if you are interested.

    hope this is a little helpful


  9. #9
    Thank you to everyone for your help. Looks like a crusher is the way to go. Chris, I will keep your kit in mind. A donor still seems the least expensive path for an engine and transmission.

    For the crusher, I don't like the idea of crushing a running antique if possible. I assume as long as it has a title, the car can be in bad shape (no engine, etc.)? How would MA know if the car has an engine or not? Also for the displacement groups, I see that the 5 and 6 cylinder group goes up to 5.0L. Does that mean I can crush a car from this 6 cylinder displacement group for a 5.0 Coyote? Or does it have to match cylinder count too?

  10. #10
    I appear to be the only one to have reuse a donor ECM and done a wire diet. Pics of before/after are here:
    Unless you you have spare time, the control pack with a donor motor is way easier.

    I did the wire diet while waiting for my kit delivery...


  11. #11

  12. #12
    Congrat's Totem on the wiring diet...
    I did a similar thing on a Chev LT-1/4L60e swap into my '65 Camino (from a '96 Buick RoadMonster) a few years ago. Spent a lot of hours with a meter and a factory manual stripping out the un-needed circuits. One cool bonus is I was able to "re-purpose" some of the OEM relays in the sub-panel to do other things.
    John D. - Minneapolis 'Burbs

    1965 El Camino - LT-1, 4L60e, 4wh discs, SC&C susp.
    2013 F-150 Platinum - Twin Turbo 3.5
    2018 Mk4 Roadster - On the way! Build Thread

  13. #13
    I tried the donor wiring harness and ECU. I also did the donor 6 speed. look in teh coupe section for Curvy Road G3 build can read all about it.

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