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Discussion Starter #1
I have been having a problem with a new 2015 gen2 Coyote crate engine. The engine starts and idles fine. That said, after depressing the accelerator pedal, the engine revs for 1-2 seconds and then goes into limp mode (remains at idle without any further response to gas pedal). I have been working with Ford Engineering since July of 2019 without any resolution. I have sent my PCM, MAF and all wiring to Ford where they hooked everything up to a stand mounted engine...everything checked out OK. Ford updated all programming in the PCM and sent everything back to me. I reinstalled all of the hardware and I am still experiencing the same problem. I rechecked the wiring between the Throttle Body and PCM as well as the APP (gas pedal fitting) and PCM and all wires indicate appropriate ohms/continuity.

I have had to cancel sending this car to Temecula so Jeff Miller can perform his magic 2X now and I am beginning to get concerned that it might be another summer without the car. Mark Dougherty has also been to my house to assist with some other final checks but we could not get the engine out of limp mode. Mark Dougherty (The Traveling Builder) is terrific by the way....highly recommended!

Any suggestions or advice would be greatly appreciated!
 

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This is the crate motor with the Ford Performance control pack? I assume the MIL is on? What codes do you see when reading the ODB2 port? I can't say how Ford has the crate motor calibration programmed, but limp mode typically limits RPM, shuts off non-essential accessories, etc. But shouldn't disengage the accelerator. I wonder if that's really the state it's going into, versus some type of outright failure. Regardless, if not working normally should see some kind of trouble code(s).
 

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Discussion Starter #3
Yes...crate motor with Ford Performance Control Pack (from Summit) and the MIL is installed. Error code is P2122. I use the term "Limp Mode" only because that is the term that Ford has used with me. Unfortunately, I am just a "weekend warrior" with 1975 high school auto mechanics background and this problem is way beyond my skill set other than checking for tests that people suggest. I would be happy to hire assistance but not sure where to go and with COVID-19, we are fairly hunkered down.
 

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Seems that code has to do with the voltage from the throttle position sensor.


Do you have a multimeter? You can use it to determine the voltage reading coming out of the TPS. If it's too low, it's a matter of backtracking to see if you have a short, faulty TPS, etc.
 

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That code is consistent with your accelerator not working. A little surprised Ford was calling that limp mode. Follow the diagnostics for the code.
 

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So the accelerator pedal and the throttle position sensor are triplet redundant. If one of the 3 don't see the same thing it will only idle. One goes high to low, one goes low to high, and the other shows closed throttle,part throttle and wide open throttle. the first 2 are voltage.
 

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just to give an update on this
the issue was the plug going into the throttle pedal.
he tested on the back side of the plug all showed well.
but
one of the pins in the plug pushed slighty back.
just missing making contact.
that simple
just push the pin in far enough to lock
and all is good
 

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Thanks for identifying the problem and sharing the solution with us.

I had a problem with a code on of my O2 sensors. Initially I replaced both O2 sensors, good for a month, then the code returned. I took the car to a shop that provided the tune for the ECU and they found that one of the O2 extension cables had a pin that wasn't making contact. They seated the pin, and the code went away. Pesky little wiring gremlins that will drive you nuts!
 
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