Coyote swap irregular stalling

Discussion in '2011+ Mustang GT 5.0L Tech' started by Jake Johnson, Feb 13, 2021.

  1. Jake Johnson

    Jake Johnson Junior Member

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    Hello all, I have a 2006 coyote swapped Mustang. The car is all done and drives great besides a few things. When I press in the clutch and put the car in neutral during deceleration sometimes the car will stall. It starts right back up when I turn the key or pop the clutch. The frequency of this happening is very low in the city but it will always stall without fail after getting off the highway and slowing down on the off ramp. Today while I was driving it, it randomly shut off at a light and would then crank but not start. I pushed it to a parking lot and returned about an hour later. When I got there I tried it again and it fired right up with no hesitation. I drove it home and here it sits. It runs like it did before but what caused it to die like that? Also, any ideas on the intermittent stalling? Thanks!
     
  2. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
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    I'd start with the very basics like thoroughly cleaning the inside of the throttle body, and cleaning the MAF sensor.
    If those measures don't work, you might want to check for a vacuum leak. Did you pull any codes?
     
  3. jewc75

    jewc75 S197 Junkie S197 Team Member

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    Sounds like a tune issue.
     
    crjackson2134 likes this.
  4. Juice

    Juice forum member

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    Who tuned it?
    Control pack or factory pcm?
     
  5. race4food

    race4food forum member

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    That sounds like a tune MAF issue. The airflow its expecting is not what its getting.
     
  6. Juice

    Juice forum member

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    Based on what info? Nothing posted so far is pointing to a maf/airflow issue yet.
     
  7. RED09GT

    RED09GT Equal Opportunity Offender S197 Team Member

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    In the tune, dashpot settings would be the first place to look.
     
  8. crjackson2134

    crjackson2134 Member

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    I’ve been told that there’s no dash pot setting for Coyote’s.
     
  9. Juice

    Juice forum member

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    Not that simple with a coyote. You may be able to band-aid it with dashpot, but if that isnt the real cause, you will be chasing your tail.
    I had a stalling issue early on, two things that were causing the issue were: throttle body data error, and the correct gear ratios entered. Gear ratios affected drivability also. But if those are not correct, it throws off the load calculations.
     
    RED09GT likes this.
  10. crjackson2134

    crjackson2134 Member

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    I have the occasional stalling problem that I’m currently dealing with. How does one diagnose a throttle body data error?
     
  11. Juice

    Juice forum member

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    I found mine by accident. I started comparing the predicted throttle table to a stock file. (I have a stock throttle body) and noticed differences at idle and off idle area. So I copied the data from the stock file into my tune and my issues were fixed.
    Not sure why the control pack strategy throttle data was different from a stock GT data, but it was.
    Bottom line, that data must be correct for the throttle body that is on the car.
    And the difference was miniscule. Less than 5% difference.
     
    crjackson2134 likes this.
  12. RED09GT

    RED09GT Equal Opportunity Offender S197 Team Member

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    I just read a bit on dashpot and the torque based decel in the copperhead ECU and yeah, seems like this is a common issue with tuning the copperhead ECU.

    Good news is that it is likely not a hardware problem
     
  13. Juice

    Juice forum member

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    If all else is good, no check engine light on, drives well, than yea. It is most likely in the tune.
     
  14. Gray5OH

    Gray5OH Junior Member

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    I experience this as well. Except my idle only “dips” most of the time. When I have the AC on, is when that dip will become a stall. Like you mine starts back up no problem. I don’t have any stock logs or anything to compare it too, but I’m running a VMP twin 67 throttle body, and from what I have read and talked with other guys about the random stalling thing seems to be a unfortunate common thing with these. I’ve went over it twice now with my tuner, Lund, and mine still does it.

    it wasn’t so bad, until one time I was merging into stop and go interstate traffic, and didn’t realized it had died until I went to hit the skinny pedal and didn’t move lol. I’m curious as to what you come up with on it.
     
  15. jewc75

    jewc75 S197 Junkie S197 Team Member

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    I have zero issues with my VMP twin 67, Lund tuned as well.
     
    Gray5OH likes this.
  16. crjackson2134

    crjackson2134 Member

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    That's my issue exactly too. After I recover from my surgery in a few weeks I’ll be making another trip to the Dyno and praying for some help with this. Sad thing is, I don’t think my tuner has the will to help me with this.
     
    Gray5OH likes this.
  17. Juice

    Juice forum member

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    I have had similiar issues w/my swap.
    Idle surge when coming to a stop was resolved in the throtle body predicted flow table. I am running a stock TB and found differences in this table when comparing it to stock. Minute differences in the off idle area.
    Car stalled easily pulling away from a stop. This was a load calculation issue and combined with my TB calibration and fuel aystem set for "return style" while running stock returnless, causing "computer confusion". As it was, it was impossible to idle away from a stop with just letting the clutch out, no throttle. (Who does that? I do sometimes) After fixing all those items, I can easily move from a stop with clutch only. (Think stop and creep 20feet traffic ;))
     
  18. Gray5OH

    Gray5OH Junior Member

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    Humm. Well that’s good to know. Well then I have no clue why mine does it then lol

    well mention to him what these other guys on here posted about the issue. Maybe it’s just a quick fix that’s getting overlooked within the tune.
     
    crjackson2134 likes this.
  19. MacClean

    MacClean Junior Member

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    Looks like a problem with generator or wires at all
     
  20. crjackson2134

    crjackson2134 Member

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    Been a while since this thread was active, but wanted to post my final solution.

    The problems I had were caused by “Fan Wash”. The CAI wasn’t isolated from the blast of turbulent hot air when the cooling fan kicked on. This caused erratic airflow around the MAF sensor. This info. discovered after watching a video posted by Shaun (AED) demonstrating the problem.

    I climbed into the loft of my storage building, and went digging through the box of extra parts from Roush. I found that the seals that close off my CAI were never installed by the shop. I installed these seals et voilà !

    Problem solved. I was shocked that 4 little rubber seals on the CAI could have such an impact.

    Case Closed (for me).
     
    nyuk98GT likes this.
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