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Eric1981

Cylinder 6 Misfire

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Hey Guys,

 

My ex wife bought an 08 Edge after we split up. I'm trying to help her with it. It had random misfire codes and a specific Cyl 6 code. I put new plugs in (motorcraft) and it runs better, and the random misfire code disappeared, but the cyl 6 stayed. I swapped coils with cyl 5 to see if it was a bad coil...but it is still saying cyl 6. I also ran some Techrom cleaner through it. I'll do a compression test soon, but I just wanted a few ideas to look at at once. Is there a pretty common problem on these cars that causes this issue? The car seems to run fine to me under acceleration and mid-high RPM, I can hit 80 pretty easy without getting on it too hard...but it sputters pretty much at idle only maybe a little still in lower RPM range.

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sounds like the coil driver for cylinder 6, located in the PCM, is at fault.  Sometimes the injector is at fault, of course.

 

Highly recommend you do all coils and have the PCM repaired by the good folks at https://circuitboardmedics.com.  the random misfires can put enough stress on the coils and PCM to warrant a proactive resolution.

 

TSB for this issue

https://drive.google.com/file/d/1ZT29kax4hFpDVTwOAvMi5AHon9PV714X/view?usp=sharing

 

and the kit you can get from Ford (coils, plugs, gaskets)

https://parts.levittownfordparts.com/oem-parts/ford-kit-ba5z12259a

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have you also replaced the PCV valve & cleaned the MAF sensor/throttle body?

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Is there a way I can test to see if it is the driver for sure? Is there a way I can get a schematic for the PCM? I am an electronics engineer, as was my dad for 40 years...I've been soldering and messing with circuit boards since I was 4 yrs old...But I understand the biggest issue is the source of the schematic to be able to repair things like that myself. Also, I don't know much about this car, she bought it shortly after our splitup cuz she blew the motor in her Pacifica by refusing to learn how to check the oil despite how many times I tried to show her in all her vehicles she had in our 5 yrs together. But it does have 190K on it...Would it really be worth the $300 to repair PCM?

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I have found being an engineer and actually repairing electronics are two different skill sets LOL.

 

But if you are willing to try, you can certainly repair the PCM yourself, you seem to have enough handson experience to do it.

 

Testing the drivers is very straightforward:

 

COILS

JB9 CHECK THE SECONDARY COIL RESISTANCE FOR THE MISSING CYLINDERS

  • Ignition OFF.
  • Suspect coil connector disconnected.
  • Measure resistance between: Suspect coil connector, IGN START/RUN, component side and ignition coil spring, located in the ignition coil boot.
Is the resistance between 5,000 and 6,000 ohms?
Yes No
GO to Pinpoint Test Z . INSTALL a new COP.

Clear the PCM DTCs. REPEAT the self-test.

 

DRIVERS

JF5 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR AN OPEN IN THE HARNESS

  • Ignition OFF.
  • PCM connector disconnected.
  • Suspect coil connector disconnected.
  • Measure the resistance between:
     
    ( + ) PCM Connector, Harness Side ( - ) COP Connector, Harness Side
    Suspect coil driver COP
Is the resistance less than 5 ohms?
Yes No
GO to JF6 . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

 

JF6 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

  • Ignition ON, engine OFF.
  • Measure the voltage between:
     
    ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
    Suspect coil driver Negative terminal
Is the voltage less than 1 V?
Yes No
GO to JF7 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

 

JF7 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

  • Ignition OFF.
  • Measure the resistance between:
     
    ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
    Suspect coil driver Negative terminal
Is the resistance greater than 10K ohms?
Yes No
GO to JF14 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. If the concern or DTC is still present,

GO to JF8 .

 

as to worth, i can't say, not knowing the vehicle's condition at time of purchase, the maintenance history, or how long she intends to keep it.  i WILL say, all fluids need to be changed immediately to get a good start.  if you hear any rattles at startup, that is a warning that the timing system/water pump need to R&R'd not too far down the road, usually around a 1500-2000$ job.  if it is an AWD vehicle, then you will have to check the condition of the PTU, driveshaft, and RDU.

 

2007 Edge COP Pinout on PCM Connector C175E.jpg

Edited by WWWPerfA_ZN0W

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19 minutes ago, WWWPerfA_ZN0W said:

I have found being an engineer and actually repairing electronics are two different skill sets LOL.

 

But if you are willing to try, you can certainly repair the PCM yourself, you seem to have enough handson experience to do it.

 

Testing the drivers is very straightforward:

 

COILS

JB9 CHECK THE SECONDARY COIL RESISTANCE FOR THE MISSING CYLINDERS

  • Ignition OFF.
  • Suspect coil connector disconnected.
  • Measure resistance between: Suspect coil connector, IGN START/RUN, component side and ignition coil spring, located in the ignition coil boot.
Is the resistance between 5,000 and 6,000 ohms?
Yes No
GO to Pinpoint Test Z . INSTALL a new COP.

Clear the PCM DTCs. REPEAT the self-test.

 

DRIVERS

JF5 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR AN OPEN IN THE HARNESS

  • Ignition OFF.
  • PCM connector disconnected.
  • Suspect coil connector disconnected.
  • Measure the resistance between:
     
    ( + ) PCM Connector, Harness Side ( - ) COP Connector, Harness Side
    Suspect coil driver COP
Is the resistance less than 5 ohms?
Yes No
GO to JF6 . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

 

JF6 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

  • Ignition ON, engine OFF.
  • Measure the voltage between:
     
    ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
    Suspect coil driver Negative terminal
Is the voltage less than 1 V?
Yes No
GO to JF7 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

 

JF7 CHECK THE SUSPECT COIL DRIVER CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

  • Ignition OFF.
  • Measure the resistance between:
     
    ( + ) PCM Connector, Harness Side ( - ) Vehicle Battery
    Suspect coil driver Negative terminal
Is the resistance greater than 10K ohms?
Yes No
GO to JF14 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. If the concern or DTC is still present,

GO to JF8 .

 

as to worth, i can't say, not knowing the vehicle's condition at time of purchase, the maintenance history, or how long she intends to keep it.  i WILL say, all fluids need to be changed immediately to get a good start.  if you hear any rattles at startup, that is a warning that the timing system/water pump need to R&R'd not too far down the road, usually around a 1500-2000$ job.  if it is an AWD vehicle, then you will have to check the condition of the PTU, driveshaft, and RDU.

 

2007 Edge COP Pinout on PCM Connector C175E.jpg

I know what you mean as far as engineer thing goes...But you are thinking along the lines of design engineer. My dad was a service engineer for MRI, Cat-scan, and x-ray equipment. The first half of his career they had to repair the circuit boards onsite, and thus I learned how to solder at a young age. While my degree was in electrical/electronics engineering, I was following his footsteps. Life has a funny way of throwing obstacles at you and thus I am now an industrial/controls electrician, but have a very deep understanding in both design and repair. I agree that many of my co-students are far from my caliber in understanding the troubleshooting aspects vs making calculations and being flabbergasted when real world components with tolerances doesn't work out the same as on paper. Thank you for the info, I didn't have time to look it over indepth yet, but it was a good skim.

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my brother's degrees are in chemical and electrical engineering, but he doesn't like to be handson with electronics lol.  he did what he had to when he was a "sales engineer" with a wellknown printer company and had to be in the field often delivering and servicing their equipment.

 

seems like you and your dad have the gumption to get in there and get it done. looking forward to your notes on this project.

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