F150online Forums

F150online Forums (https://www.f150online.com/forums/)
-   2004 - 2008 F-150 (https://www.f150online.com/forums/2004-2008-f-150-80/)
-   -   2008 F-150 STX 4x4 with a 4.6L, wiring diagram needed for PCM. (https://www.f150online.com/forums/2004-2008-f-150/525178-2008-f-150-stx-4x4-4-6l-wiring-diagram-needed-pcm.html)

SiskCFRN 09-26-2021 12:23 PM

2008 F-150 STX 4x4 with a 4.6L, wiring diagram needed for PCM.
 
Working on the latest mechanical debacle with my ‘08 F-150. It’s a four wheel drive STX with the two valve 4.6L. I need the wiring diagram for where the harness connectors plug into the PCM. Wanting to check continuity of the control wires for the COPs. The truck shakes like a cylinder is misfiring, but only slightly at idle, and a lot between 1200 and 1400 RPM while driving. I can’t feel anything abnormal at 2000 RPM or above. Code says “coil C primary/secondary”.
The coil tests 5.95 ohms from both the power and the control terminal to the end of the spring. All the plugs are new Motorcraft plugs. The connector is good. The power wire shows 12.1 volts with the switch on. I’ve put a test light on the #3 coil control wire & battery positive with the engine running & the test light blinks, but I was thinking the wire could be partially broken or shorted to power somehow.

projectSHO89 09-26-2021 02:32 PM

https://cimg1.ibsrv.net/gimg/www.f15...8150f92dbe.png

glc 09-26-2021 05:08 PM

Have you actually tried swapping coils?

SiskCFRN 09-26-2021 05:36 PM

I haven’t. I’ll swap #3 with #2 & reset the check engine light today. Supposed to leave it with a mechanic this week to have the valve cover gaskets replaced, and I’m going to ask him to check for a vacuum leak while he has it.

SiskCFRN 09-26-2021 07:35 PM

Now I know why it threw a coil C primary code.
 

Originally Posted by glc (Post 5273006)
Have you actually tried swapping coils?

I pulled that new #3 coil to swap with #1, and realized the power prong was bent against the top of the plug. Even though the connector clicked each time, the power prong wasn’t inserting into the power pin. I straightened the prong, but still swapped it with #1. Drove it a couple miles & back. No check engine light now, but the vibration is still there at 1200 rpms, and it still doesn’t idle well in gear. Thanks for reminding me to swap it with another.
https://cimg1.ibsrv.net/gimg/www.f15...3ab3aa76d.jpeg

SiskCFRN 09-27-2021 09:30 AM

Problem solved.
 

Originally Posted by SiskCFRN (Post 5273008)
I haven’t. I’ll swap #3 with #2 & reset the check engine light today. Supposed to leave it with a mechanic this week to have the valve cover gaskets replaced, and I’m going to ask him to check for a vacuum leak while he has it.

That new coil that had the bent prong on it was bad. Threw another check engine light this morning & when they read it, same error, except in #1 now. So they made it up, and I replaced it in the parking lot.
I’d been driving it in limp mode for a week, and the exhaust had already started making a clanging sound. That went away when I replaced the coil. Thanks for both y’all’s help.


All times are GMT -4. The time now is 01:13 PM.


© 2024 MH Sub I, LLC dba Internet Brands