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Thread: Ford PCM controlled starting

  1. #1

    Ford PCM controlled starting

    I have a question regarding how the Ford PCM controls the starting function in the Coyote. Does the input require a momentary signal which then activates the starter to operate until the engine is running? Or does the input require a constant source of power which when disconnected manually interrupts the operation of the starter?

    In other words, do you have to hold the key in the start position until the engine is running or can you simply activate the circuit, let the key back to the run position, and the PCM will decide when to turn off the starter?

    FYI, I have the 2015 crate version of the Coyote.
    FFR MK4 #8849. 2015 Coyote, 2015 IRS.

  2. #2
    Senior Member
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    I used the Ron Francis start circuit with a Relay from the Coyote control pack clutch switch for a safety .

    I do not like how it stays engaged until it starts. After thinking about this. I remembered I used the Ron Francis start circuit on all of the builds I have done with the '15 coyote.

    Earlier than '15 cars did not behave this way and they required the key to be held on.
    Last edited by FFinisher; 04-23-2017 at 10:35 AM.
    FFinisher/AKA RE63

  3. #3
    My 2015 coyote the key works like a start button. Momentary activation and then you can let go and it will
    Continue to crank until it fires.
    Conflicting info with the previous post but that is how mine works.
    MK4 #8900 - complete kit - Coyote, TKO600, IRS - Delivered 6/28/16 First Start 10/6/16 Go cart - 10/16/16 Build completed - 4/26/17 - 302 days to build my 302 CI Coyote Cobra - Registered and street legal 5/17/17
    Build Thread http://thefactoryfiveforum.com/showt...e-build-thread
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  4. #4
    Senior Member edwardb's Avatar
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    Quote Originally Posted by wareaglescott View Post
    My 2015 coyote the key works like a start button. Momentary activation and then you can let go and it will
    Continue to crank until it fires.
    Conflicting info with the previous post but that is how mine works.
    Same here. If you wire the 2015 Controls Pack using only the Coyote PDB and PCM for the start function, it works like a start button. It only requires an ignition sense and start sense signal from the RF harness. The Coyote system handles everything else. Once the +12V signal is received from each, whether you hold the key in the start position or not, the starter spins until the engine starts. Usually very quickly. No surprise since the Mustang GT also has a start button. Note this is different than how FF shows in the Coyote installation manual, where the RF circuits and solenoid are used.
    Last edited by edwardb; 04-21-2017 at 10:39 AM.
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  5. #5
    Senior Member 2bking's Avatar
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    I have the 2014 controls pack and wired for the PCM to control starting. The start button has to be held until the engine starts.
    King
    Roadster #8127, ordered 7/12/13, received 9/11/13
    http://thefactoryfiveforum.com/showt...4-Coyote-Build

  6. #6
    Thank you for the replies. I also called Ford racing Friday and they told me it only requires a momentary push. Today I tried to start the engine for the first time and found I had to hold the key in the start position until the engine fired. Unfortunately it only runs for 1.5 seconds before sputtering out. Sometimes it will kick and sputter for 3 seconds but always quits on its own. I have 55psi on the fuel pressure gauge before starting. What do you guys see on the gauge while it is running?
    FFR MK4 #8849. 2015 Coyote, 2015 IRS.

  7. #7
    Senior Member edwardb's Avatar
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    Quote Originally Posted by Kerns BBO View Post
    Thank you for the replies. I also called Ford racing Friday and they told me it only requires a momentary push. Today I tried to start the engine for the first time and found I had to hold the key in the start position until the engine fired.
    That doesn't quite make sense. Assuming it's wired for PCM starting, the ignition key acts like a start button as others have mentioned and you confirmed with Ford. Apparently, based on 2bking's response, different than the Gen 1 Coyote.

    Quote Originally Posted by Kerns BBO View Post
    Unfortunately it only runs for 1.5 seconds before sputtering out. Sometimes it will kick and sputter for 3 seconds but always quits on its own.
    It would be easy enough to have someone watch your fuel pressure gauge and confirm it's holding pressure while starting and during the time before it quits. What should be happening is when to turn the key to "on," the fuel pump starts but only runs briefly. It doesn't keep running at that point. I've been able to confirm there is no pressure sensor, so apparently it's a timed circuit. It runs for a certain period of time, like a second or two, then switches off. When the start sequence is initiated, the fuel pump is started again and of course continues to run while the engine is running.

    Assuming you have continuous fuel pressure even though the engine stops running, check your MAF sensor. It's either not plugged in or it's installed backwards. What your experiencing is the exact symptom of the MAF sensor not working as it should. The PCM will shut the engine down almost immediately if it doesn't get a good signal from that sensor.

    Quote Originally Posted by Kerns BBO View Post
    I have 55psi on the fuel pressure gauge before starting. What do you guys see on the gauge while it is running?
    Still 55 psi.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
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  8. #8
    Senior Member 2bking's Avatar
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    Quote Originally Posted by 2bking View Post
    I have the 2014 controls pack and wired for the PCM to control starting. The start button has to be held until the engine starts.
    I can't be certain my PCM won't start the engine without the button being held because I have the Infinity Box Wiring. After studying my wiring diagrams, I used the Infinity Box one button starting and that signal comes from the Infinity Box logic. Sorry for the misinformation.
    King
    Roadster #8127, ordered 7/12/13, received 9/11/13
    http://thefactoryfiveforum.com/showt...4-Coyote-Build

  9. #9
    Ding ding ding, we have a winner! MAF was backwards. The car runs great now. Thank you FF forums!
    FFR MK4 #8849. 2015 Coyote, 2015 IRS.

  10. #10
    Senior Member edwardb's Avatar
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    Quote Originally Posted by Kerns BBO View Post
    Ding ding ding, we have a winner! MAF was backwards. The car runs great now. Thank you FF forums!
    Cool! When everything is right, they just run. Congrats.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
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  11. #11
    A quick update in case anyone runs into the same issues I did.

    I am using the Digital Guard Dawg key-less ignition. It turns out they had a large batch of switches which were bad from the manufacturer. If you are having odd problems and the ignition is not behaving normally this could be the problem. There are four wires connected to the switch. Check continuity between the black and white wires. These should directly correlate to the position of the switch. If they do not consistently follow the switch position call and get a replacement.
    FFR MK4 #8849. 2015 Coyote, 2015 IRS.

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