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Champion plug may have solved a misfire 5.4 3v

 
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Old 06-22-2019, 06:13 PM
mikekerr
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Champion plug may have solved a misfire 5.4 3v

My 2007 5.4v 3v with 120k miles had a misfire on cylinder 5. Pulled over and discovered the plug was loose. Torqued it down, and went on my way. 5,000 miles later, another misfire, same cylinder. Pulled the plug, and the electrode ground had broke off, not a good thing. I replaced the plug with Motorcraft, still had a misfire. Replaced the COP, still had a misfire. I was suspecting cylinder damage from the spark plug electrode ground. I did not have the means for a compression test, so sent the F350 off to the local ford dealer.

I want to note the misfire would occur within one mile of start up, and a definite loss of power immediately upon start up. It also took two seconds to start the truck typically took one second.

Ford dealer had the truck for six weeks trying to find the problem. Yes, six weeks. The replaced the spark plug, COP, fuel injector, and ran a compression test. They could not figure it out, and said I might need to replace the PCM. I said no, and I picked up the truck.

I read 100 pages of threads on the this Modular V8 forum looking for clues. Found where a guy posted carbon issues might cause the plug to not seat right. I bought a scope, and looked at the spark plugs seat, threads, and top of piston. Did not see anything that could help clarify the issue, but the piston did look black.

Bought a Champion plug, it has a very different design than the Motorcraft, More threads, beefier nut, bigger surface where the plug meets the head, and an old traditional electrode ground. Decided it was worth a try.

Removed the Motorcraft plug, and sprayed about 1/3 of a can of carb cleaner into the spark plug hole. Let the cleaner sit for about one minute. STARTED THE TRUCK UP WITH THE SPARK PLUG MISSING, SO WHATEVER CAME LOOSE FROM THE CARB SPRAY CAME HOPEFULLY CAME OUT THE SPARK PLUG HOLE. Had a fire extinguisher handy if needed. Let the truck run for about 30 seconds, and shut it off. I should also note I had the cable to the COP disconnected, to reduce a spark risk to the carb cleaner, fuel going into the cylinder.

Installed the Champion plug. Truck started right up. Went around the block, no loss of power. Checked toe code reader, no codes. Decided to go to Home Depot with the truck, which is over a major mountain, with a speed limit of 65 mph. No power issues, no misfires, no codes.

Carbon build up? Motorcraft plugs not seating well after driving with a loose plug, where a Champion seated better? I don't know- all I know is my truck is back to normal.
 
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Old 06-23-2019, 05:22 AM
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Originally Posted by mikekerr View Post
Carbon build up? Motorcraft plugs not seating well after driving with a loose plug, where a Champion seated better? I don't know- all I know is my truck is back to normal.
That is interesting---for what I've read about the 3V engines is Champion first introduced their one-piece plugs soon after the Motorcraft plugs were breaking due their two-piece construction. That alone shouldn't account for better ignition of that one cylinder---your speculation could be 100% valid.

Glad you got this sorted out---dealing with a minor persistent misfire on #7 myself---new plug, brand new Motorcraft COP and replaced the connector end too---theoretically all should be perfect and yet.............P0307 keeps popping back up, attendant rough idle right along with the DTC. I'll swap everything out once again but since I have a 2V 5.4 it'll be another new MC plug and COP.

Funny how something seemingly so easy to diagnose and fix resists being repaired huh?
 
 


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