Will a misfireing plug always pull an error code?
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5th Wheeling
Joined: Jan 2010
Posts: 35
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Will a misfireing plug always pull an error code?
I changed the spark plugs out in my V10 6.8 yesterday, and it's running a little rough now. It feels like it's missing on one 1cyl but I don't have a CE light and when I get on it, it revs fine and has plenty of power. It just runs a little rough at idle and when I lug it, it runs really rough.
I have verified all the plug / coil connections are tight and connected. If it was really missing, say one of the coil boots wasn't in contact with the plug, would it always pull an error code / CEL?
Thanks,
Chris
I have verified all the plug / coil connections are tight and connected. If it was really missing, say one of the coil boots wasn't in contact with the plug, would it always pull an error code / CEL?
Thanks,
Chris
Cargo Master
Joined: Jan 2008
Posts: 2,566
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From: The Great White North!
No not always a CEL light, especially if you have a COP on its way out, with an intermitant misfire.
Have you tried scanning for any codes?
The other thing if you suspect a COP, but no codes is to spray around the area of the cops with a water vinegar mix from a spray bottle while engine running. If you have any about to go, they should throw a code.
The other usual culprit is a disconnected/ broken air vac line, especially on the pass side, where things are tight to get around.
Have you tried scanning for any codes?
The other thing if you suspect a COP, but no codes is to spray around the area of the cops with a water vinegar mix from a spray bottle while engine running. If you have any about to go, they should throw a code.
The other usual culprit is a disconnected/ broken air vac line, especially on the pass side, where things are tight to get around.
FTE Leadership Emeritus
Joined: Sep 2000
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From: Stephensville WI
A misfire will not always trigger a Ceck Engine Light (CEL). Before a CEL is triggered, there has to be X number of misfires within a set period.
HOWEVER, it will throw a pending code. The pending codes are what is counted. If enough happen within a set period you get a CEL staring you in the face. This is one situation where it is important to use a scanner that can read the pending codes. Not all of them do.
HOWEVER, it will throw a pending code. The pending codes are what is counted. If enough happen within a set period you get a CEL staring you in the face. This is one situation where it is important to use a scanner that can read the pending codes. Not all of them do.
Posting Guru
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How will spraying water and vinegar make a failing cop more visible to the computer than it already is?
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Logistics Pro
Joined: Aug 2007
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From: Millersburg, OH
If you go to Advanced Auto (not sure about Auto Zone) they will loan you a scanner similar to the one pictured below. If you have enough misfires it will store it as a Pending Code and not as a normal Code. Like redford said a misfire will not set a CEL in vehicles over 8500 GVWR since they do not have to follow OBD-II compliance.
Once viewing Pending Codes it will tell you the cylinder(s) that have a misfire if indeed that is the problem.
Once viewing Pending Codes it will tell you the cylinder(s) that have a misfire if indeed that is the problem.
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Cargo Master
Joined: Jan 2008
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From: The Great White North!
Last summer I spent a day fishing with a Ford tech, the one they call out, or turn to when the techies at the shop have no clue how to diagnose problems. It was a good conversation that we had about the V-10's and water intrusion, cleaning engines, so on and so forth. When ever they get a problem vehicle that is misfiring, but not throwing codes this is the procedure they use.
This was after I had pulled out a psd out of the water.(back end only in the water, and would not start, after leaving it running for 1/2 hr after the extraction) Suspect water in fuel. He went over, with no real tools was able to fire it up, and was able to diagnose. Fishing was slow, so we got talking, he is the #'s guy that has to document everything.
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FTE Leadership Emeritus
Joined: Jul 2002
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From: Long Island USA
Depending on the year, a Superduty gas engine will NOT log misfire codes.
Read here:
https://www.ford-trucks.com/forums/5...t-come-on.html
Read here:
https://www.ford-trucks.com/forums/5...t-come-on.html
Thread Starter
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5th Wheeling
Joined: Jan 2010
Posts: 35
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Depending on the year, a Superduty gas engine will NOT log misfire codes.
Read here:
https://www.ford-trucks.com/forums/5...t-come-on.html
Read here:
https://www.ford-trucks.com/forums/5...t-come-on.html
I pulled the truck apart last night, checked all the plugs, plug boots, COP, and hose connections. As I was just finishing up I found a fuel injector connector that had a broken tab. It look tight but the electrical connection was backing off. I pushed it in tight and restarted the truck and it runs like a top.
So where can I buy a new electrical connection for a fuel injector? Can I just cut and solder in a new one?
Thanks,
Chris
